P. Meera Khan (1935-1998)

i Following a short hospitalization for liver cancer, Prof. Prof. Meera Khan, known to his friends and colleagues as Meera Khan, member of the editorial board of this journal, Meera, was born in Ambajipeta, Andhra Pradesh state, India, passed away on 1 April last year. He left behind his wife in 1935 and graduated from Andhra Medical College, Prabha, two sons and four grandchildren. Visakhapatnam, in 1959. During this period he had the

By H.F.A. VASEN, The Netherlands Foundation for the Detection of Hereditary Tumours, Leiden University Medical Centre, Poortgebouw Zuid, Rijnsburgerweg 10, 2333 AA Leiden, The Netherlands; Department of Gastroenterology, Leiden University Medical Centre, Leiden, The Netherlands; Department of Endocrinology, University Hospital Utrecht, Utrecht, The Netherlands.

Journal of Genetics, Vol. 78, No. 1, April 1999 63 H. E A. Vasen

unique fortune to come into contact with J.B.S. Haldane, of ideas, unrestricted access to a personal library of books who was interested in establishing genetic studies on disease and periodicals, and his numerous thought-provoking resistance in human populations. In Meera Khan Haldane scientific and popular articles. The outcome of the study on saw someone with the interest and ability to set up such the frequency of consanguinity in Andhra Pradesh was investigations, and in 1959 convinced him to commence published in the Journal of Heredity (Dronamraju and research on the relationship between consanguinity and Meera Khan 1960). The publication was the first of more inherited diseases. For Meera this was the start of a 40-year than 250 scientific contributions made by Meera Khan over career in human genetics. the years. This career can be roughly divided into three periods, After completing the study, Haldane introduced Meera to with different lines of research. From 1959 until 1965 he Marcello Siniscalco, an Italian geneticist who was working conducted several studies in India and Italy under the on genetically determined abnormalities alleged to give pro- patronage of Haldane. In 1966 he joined the Department tection from malaria. Siniscalco had found that the of Human Genetics, State University of Leiden, The frequencies of thalassaemia and enzyme deficiencies were Netherlands. Over the following years, he developed new both high in the formerly malarial areas of Sardinia. He was methods for analysing the isoenzymes present in somatic interested in performing comparable studies in an area of cell hybrids. These analyses were to play a major role in gene India from where malaria had not yet been eradicated. In mapping. Then, around 1980, his interest shifted to cancer 1962, to learn the techniques, Meera worked with Siniscalco genetics. in Naples and in Sardinia. In the same period, he visited This article tries to summarize his scientific contributions London and had discussions with two of Haldane's former over the years. Information on the first period was derived colleagues, Harry Harris at King's College and L.S. Penrose mainly from an article written by Meera himself, entitled at the Galton Laboratory. Both visits made a lasting impres- 'Some of my reminiscences of Prof. J.B.S. Haldane' (Meera sion on Meera, and greatly influenced his further scientific Khan 1993). Information on the second period was collected career. In 1963 the study suggested by Siniscalco was from his thesis (Meera Khan 1971) and his extensive carried out on the western bank of the fiver Godavari at scientific publications. I had the opportunity to collaborate Polavaram, India, where epidemics of Plasmodium falci- with Meera Khan during the most recent period. Part of the parum malaria had occurred. Meera, an officer of the Andhra information on this period is thus drawn from personal Pradesh Government Medical Services, was in charge of the experience; the remaining is derived from his colleagues and expedition at the Indian end, while Siniscalco was respon- Ph.D. students. sible for planning and directing the project. Unfortunately, in the same period, Haldane was diagnosed with rectal cancer and was therefore unable to join the expedition. He 1959-1965: The first steps in genetic research died of metastatic disease on 1 December 1964. Haldane's under J.B.S. Haldane death marked the end of the first period in Meera Khan's career, which had been so strongly characterized by the In 1959 Meera Khan was in the final year of his medical special relationship between them. In 'Some of my remini- training at Andhra Medical College in Visakhapatnam in scences of Haldane' Meera wrote that it was difficult for Andhra Pradesh when he attended a lecture by J.B.S. him to ascertain whether he was Haldane's student, disciple, Haldane, who had migrated to India in the 1950s. Haldane associate, colleague, collaborator, prot~g& or beneficiary. was well known in India both for his scientific articles and However, it is clear that Haldane's lessons had laid the basis for his popular writings in the newspaper The Hindu. Shortly for his further career. Haldane had taught the members of after the lecture, one of Haldane's coworkers discussed his Human Genetics Team 'to search for, and discover new various research programmes with Meera Khan. One of the scientific truths and to spread old ones'. In addition, he topics they discussed was the widespread practice of consan- reminded them regularly of the principles of moral courage, guineous marriages in Andhra Pradesh and the relevance of scientific honesty, and intellectual integrity. In the following this to inherited diseases. Haldane wanted to conduct a study section it will become clear how Haldane's principles had on this subject and proposed to involve Meera, who at that also become those of Meera. time was a full-time house surgeon at the King George Hospital (Visakhapatnam). Motivated by the clinical relevance of the project and inspired by Haldane's enthusiasm, 1965-1980: The early period in Leiden: somatic cell Meera agreed to perform the study in his spare time. From hybridization and gene mapping then on he became part of Haldane's so-called Human Genetics Team in India. He regularly visited Haldane at In 1965 Meera joined the Department of Human Genetics at home (Calcutta) to discuss the progress of the study. Each the State University of Leiden, The Netherlands, which had of these visits was--as Meera himself put it--like a new just then been established by Marcello Siniscalco. Under the chapter in his growing book of learning. The facilities for leadership of Siniscalco, he started studies using the study provided by Haldane included a continuous flow technique of somatic cell hybridization. The successful

64 Journal of Genetics, Vol. 78, No. 1, April 1999 Meera Khan

demonstration of the occurrence of mammalian somatic cell number of enzyme markers in human and animal cells hybridization in in vitro cultures in the early sixties had given grown in vitro and in the somatic hybrids between them. In biologists new food for thought. Usually, an attempt to graft particular, an electrophoretic-autoradiographic procedure a piece of tissue from an individual of one of the higher was devised for characterization of the enzyme HGPRT organisms to another of the same species results in rejection. in the human-mouse cell hybrid. The distinction between As a consequence, the finding (reported by Barski et al. in murine and human HGPRT has been of critical importance 1960) of fusion between two types of mouse tumour cells in deciding whether the exceptional hybrid clones identified astonished biologists. Barski's work was soon confirmed, were the result of backmutation at the murine HGPRT and then extended to other established cell lines derived locus or breakage of the human X chromosome. Meera from diverse strains of laboratory mice. The phenomenon of studied a large series of hybrid clones derived from the chromosomal loss and segregation first observed in mouse- fusion of HGPRT-deficient mouse cells with human diploid mouse somatic cell hybrids had encouraged optimism. In cells for their G6PD patterns. He found that about half of the meantime, Littlefield (1964) had developed a model for them were exceptional in the sense that they possessed only isolating pure hybrid cells by selecting against biochemi- murine G6PD, even though their HGPRT was of the human cally marked parental cells by means of a selective medium. type. These findings suggested mitotic separation of the Ephrussi and Weiss (1965) obtained a cross between cells two human X-linked genes, and set the basis for studies on derived from mouse and rat, announcing for the first time X-chromosome mapping at the level of somatic hybrid that the interspecific barrier evidently does not apply to the cells. In addition, a large series of human-mouse and fusion of somatic cells in vitro, and that cells from the most human - Chinese hamster hybrid clones were studied for diverse species can be induced to fuse and to form viable their HGPRT, G6PD and PGK patterns in order to prove somatic hybrids. Harris and Watkins (1965) were able to the hypothesis of X linkage of the human PGK locus increase the efficiency of fusion considerably by using UV- suggested by one human pedigree segregating for a deficient inactivated Sendai virus as a fusing agent. The combined mutant at this locus. The results of Meera's studies gave use of this fusion technique and the Littlefield selective conviffcing support to the X linkage of human PGK, and procedure had been of great significance for the advance- demonstrated the versatility of somatic cell hybrids for the ment of studies of somatic cell hybrids. Weiss and Green mapping of the human X chromosome. The results of these opened a new approach to the mapping of human chromo- and related studies were the subjects of a series of papers somes by producing human-mouse somatic cell hybrids in published in Nature and other journals, and were presented 1967. Both the parental genomes were found to be simulta- as a doctoral thesis in 1971 (Meera Khan et al. 1971; neously functional inside the interspecific hybrid cells. Ruddle et al. 1971; Westerveld and Meera Khan 1972). However, within a few generations of their formation, the The thesis (Meera Khan 1971)--awarded cum laude-- human-mouse hybrids were found to have undergone a immediately became a bestseller, and for more than ten preferential, random loss of human chromosomes. It was years was the standard 'recipe book' for the enzyme soon realized that this type of interspecific hybrid would analysis of somatic cell hybrids. These analyses were to play become a precious tool for studies of human genetic linkage, an important role in general, and in the significant Dutch specifically for (i) the chromosomal assignment of those contribution to gene mapping in the years between 1972 and genetic markers for which the mouse parental cell line is 1983 in particular. deficient, and whose presence is essential for the survival of the cell hybrid in the selective medium; and (ii) the detection of autosomal linkage, in view of the fact that all human 1980-1998: Cancer genetics structural loci located on the same chromosome tend to be lost or retained together, and that most of the human gene In the early 1980s, Meera Khan's interest shifted to cancer, products are clearly and easily distinguishable from their especially to hereditary colorectal cancer and hereditary murine homologues. Meera Khan's studies in the early breast/ovarian cancer. The best-known inherited forms of period in Leiden focussed on (i) developing rapid techni- colorectal cancer are familial adenomatous polyposis (FAP) ques for the electrophoretic characterization of a number and hereditary nonpolyposis colorectal cancer (HNPCC). of enzyme markers on cellulose acetate gels suitable for FAP is an autosomal dominant disease characterized by studying large numbers of somatic cell hybrid lines and the development of hundreds or thousands of colorectal clones of different kinds and their parental cells; (ii) adenomas early in life. If the colon is not removed, the analysing the behaviour of X-linked markers (HGPRT and polyps inevitably lead to adenocarcinoma. HNPCC is a G6PD) in a series of clones derived from a set of human- dominantly inherited condition associated with a marked mouse hybrids, where the separation of the loci for these increase in cancer susceptibility, especially to cancer of the markers had been reported; and (iii) checking the alleged X colorectum and the endometrium. Hereditary breast/ovarian linkage of human PGK at the somatic cell level Meera cancer is an antosomal dominant condition characterized by successfully developed easy, reliable and inexpensive the development of breast and/or ovarian cancer at an techniques for the electrophoretic characterization of a unusually early age.

Journal of Genetics, Vol. 78, No. 1, April 1999 65 H. E A. Vasen

Adenosine deaminase aimed at the development of diagnostic tools to identify In the field of cancer genetics, Meera Khan's group con- carriers of the FAP gene. ducted a series of studies on adenosine deaminase (ADA) In 1986 Herrera reported an interstitial deletion in and its complexing protein (ADCP). A complete deficiency chromosome 5 in an FAP patient with multiple congenital of this enzyme is known to be the metabolic basis for an anomalies (Herrera et aL 1986). This finding gave the first autosomal recessive form of severe combined immuno- hint of the chromosomal location of the polyposis gene. deficiency (SCID) disease. Earlier studies showed that Inspired by this report, two groups working independently expression of the gene for ADCP might be altered during found that the gene causing FAP was linked to chromosome malignant transformation. The studies by Meera's group 5 at q21-q22 by using the DNA marker Cllpll, which had (which led to four theses) provided information on the already been localized to this region (Bodmer et aL 1987; possible physiological function of ADCP and its significance Leppert et al. 1987). The low frequency of the variation as a marker in neoplastic transformation. Cllpll made it useful in less than 20% of the families. Meera Khan's group searched for linkage with other markers, and subsequently showed that two other linked polymorphic Familial adenomatous polyposis markers, Pi227 and YN.48, closely flank the FAP locus, one In 1981 a national collaborative group of specialists with on either side. For the first time, this finding--which was a special interest in polyposis was established in The reported in The Lancet--allowed prenatal and presympto- Netherlands; it was chaired by Prof. E. van Slooten. The matic diagnosis of FAP with more than 99.9% reliability in group set up a central registry of families with this disorder the majority of families (Tops et al. 1989). In addition, his (The Netherlands Polyposis Registry) to promote surveil- group identified several other new polymorphic markers lance in the families and to promote research. In collabora- which further improved the presymptomatic prediction of tion with the Department of Gastroenterology at the FAP. In 1991 the APC gene was cloned, making direct University of Leiden (Dr G. Griffioen and Prof. Haex), mutation analysis possible (Groden et al. 1991; Kinzler et aL Meera, an active member of this group, started a project 1991).

Meera Khan and Prof. E. van Slooten, founder of the Netherlands Polyposis Registry.

66 Journal of Genetics, Vol. 78, No. 1, ~.pril 1999 Meera Khan

Three years later, Meera applied a new technique, the Fodde et al. 1994; Oshima et aL 1995). The Min mouse protein truncation test, for the detection of translation- carries a mutation at codon 850, which results in a truncated terminating mutations at the FAP gene (van der Luijt et al. polypeptide of about 100 kDa. These mice develop approxi- 1994). This test greatly facilitated the mutation analysis of mately 100 adenomas throughout the intestinal tract. The FAP. Another project set out to determine whether the mole- Apc TM mouse model carries a mutation at codon 716, which cular heterogeneity at the APC gene in FAP might account results in a short truncated protein and the development of for the phenotypic variability of the disease observed among 200-500 intestinal adenomas. The Apc1638N mouse model patients. A relatively mild form of FAP, designated as was developed in Meera's laboratory by introducing a attenuated FAP and characterized by a highly variable but neomycin phosphotransferase expression cassette at codon generally low number of adenomas, had been associated with 1638 in transcriptional orientation opposite to that of Apc mutations at the 5 ~ end of the APC gene. Meera's group (Fodde et al. 1994). In addition to attenuated polyposis of the reported several families with a distinct phenotype associated upper gastrointestinal tract, these animals develop multifocal with mutations at the 3 t end of the gene (van der Lnijt et al. cutaneous cysts and desmoid tumours (Smits et aL 1998). 1994; Scott et al. 1995; Eccles et al. 1996). Detailed clinical Western analysis failed to detect the expected truncated and genetic studies of these families provided clues to the polypeptide, which suggested that these mice carry a null aetiology of this atypical phenotype of FAP. Apc allele. Subsequent immunoprecipitation analysis of Another question was how to implement the results from protein lysates of Apc+/Apc1638N animals revealed the molecular-genetic studies in general practice (also referred presence of minimal amounts of the predicted 185-kDa to as translational medicine). An example of translational truncated protein. Comparison of the Apc1638N and Min medicine was a study reported in The Lancet which showed animals on identical genetic backgrounds and in the same how knowledge on the site of mutation at the APC gene animal facility showed a significantly milder phenotype in might be used in decision making on the surgical treatment Apc1638N. In the second murine lineage developed in of FAP (Vasen et al. 1996). Meera's laboratory, the Apc1638T model, the neomycin phosphotransferase gene was inserted at exactly the same nucleotide position in Apc as in the Apc1638N lineage, but in European Community Concerted Action on FAP and HNPCC (EUROFAP) the same transcriptional orientation as Apc. As a result, a stable truncated polypeptide of about 185kDa was synthe- EUROFAP was a European collaborative group of specia- sized. One-year-old Apc1638T mice are free of intestinal lists, mainly clinical and molecular geneticists with a special tumours, suggesting that the truncated protein retains its interest~in FAP. Its meetings received financial support from tumour-suppressive function. the EuroPean Community. The aims of the collaborative These results have greatly contributed to our understand- group were to promote the establishment of efficient FAP ing of the relationship between genotype and phenotype in registries, to develop marker systems for presymptomatic FAP. Possibly, the presence of a short truncated Apc poly- diagnosis, and to coordinate genetic studies in HNPCC. peptide accounts for severe intestinal phenotypes, whereas Meera Khan and Jan Mohr (University of Copenhagen, longer truncated proteins retain most of Apc functions. Denmark) were the organizers of the EUROFAP workshops, Accordingly, null or leaky mutations leading to a reduction which were held between 1990 and 1994. The group also of intracellular Apc lead to relatively milder phenotypes organized a genetic course on testing for FAP for geneticists resembling the attenuated FAP syndrome. These observa- from various centres in Europe. The ultimate 'deliverable' tions have been confirmed by the team led by Meera through of the EUROFAP programme was a reduction of cancer detailed analysis of human kindreds characterized by atypical casualties in the European Community. FAP phenotypes (Scott et al. 1995; Eccles et al. 1996; van der Luijt et al. 1997). Furthermore, study of these mouse models has shown that the normal Apc protein is required for Mouse models embryonal development (Fodde et al. 1994). Meera's studies coordinated by Riccardo Fodde also contributed to the development of mouse models for FAP. Hereditary nonpolyposis colorectal cancer Studies on these mouse models contributed to our under- standing of the relationship between genotype and pheno- In the 1980s, Meera Khan's work on cancer genetics was type in FAP. Studies on mice carrying germ-line mutations at extended with molecular-genetic studies in HNPCC. The the murine homologue of APC, the Apc gene, have shown genetic basis of HNPCC was discovered by American and that the phenotypic expression of these mutations is influen- Scandinavian investigators in 1993 (Lindblom et al. 1993; ced both by genetic background and by external factors such Peltomaki et al. 1993). It was found that the syndrome is as diet. At least four different mouse models for FAP have caused by germ-line mutations in one of the genes respon- been generated by several research groups including Meera sible for the repair of DNA mismatches occurring during Khan's: these include Min (multiple intestinal neoplasia), DNA replication (the mismatch repair genes: MLH1, MSH2, Apc1638N, Apc1638T and ApcTM (Moser et al. 1990; MSH6, PMS1 and PMS2) (Fishel et al. 1993; Leach et aL

Journal of Genetics, Vol. 78, No. 1, April 1999 67 H. E A. Vasen

1993; Bronner et aL 1994; Papadopoulos et al. 1994). In The Hereditary breast cancer Netherlands, the National Polyposis Registry was extended For many years, clinical observations had suggested the with HNPCC families, thereby allowing Meera's group to existence of families in the general population with a predis- perform genetic studies. The studies focussed mainly on the position to breast cancer. A population-based study by establishment of specific mutation detection strategies, to Newman in 1988 showed that 5% of all breast cancers have a facilitate presymptomatic diagnosis, to estimate cancer risks hereditary basis (Newman et aL 1988). In 1990 Hall and in the affected families, and to establish genotype/phenotype others reported the first breast cancer susceptibility gene correlations. His group identified many new mutations in (BRCA1) that was localized to chromosome 17q by linkage MLH1 and MSH2 (Wijnen et al. 1995, 1996). A recent study analysis in families with an early age of onset of the disease published in Nature Genetics after Meera's death indicated (Hall et al. 1990). In collaboration with P. Devilee and C. that hMSH2 genomic deletions are frequent in HNPCC Cornelisse, Meera Khan performed linkage analysis in Dutch (Wijnen et al. 1998a). Another study published in the New families as part of an international collaborative study (The England Journal of Medicine was aimed at identifying Breast Cancer Linkage Consortium). The study showed that clinical findings which predict the outcome of genetic testing in 45% of the families with only breast cancer, and in nearly in families suspected of HNPCC (Wijnen et al. 1998b). 100% of the families with breast and ovarian cancer, breast Mutation analysis was performed in 184 families with cancer was linked to BRCA1 (Easton et al. 1993). Meera's clustering of colorectal cancer. Mutations were found in group also performed studies on loss of heterozygosity about 25% of the families. A much higher frequency of (LOH) in sporadic and familial breast cancer. A small detection of mutations was reported for families that met proportion of the sporadic tumours showed LOH in a region the clinical (Amsterdam) criteria for HNPCC (about 50%) that contains the BRCA1 gene (Cornelis et aL 1993). than for families (< 10%) which did not comply with the However, the same proportion of tumours showed LOH criteria. The study showed that an early mean age at distal to BRCA1, suggesting that this region may contain diagnosis of colorectal cancer in the family, compliance with another gene involved in breast cancer. In a collaborative the Amsterdam criteria, and the presence of at least one case study of tumours from patients belonging to families with of endometrial cancer in the family were independent predic- hereditary breast cancer, LOH was detected in 86% of tive factors in finding a mutation. Using the outcome of the tumours of families with a high probability of linkage with study, a logistic model was developed that could be used to BRCA1, and invariably involved the wild-type allele calculate the probability of detecting a mutation on the basis (Cornelis et al. 1995). The BRCAl-induced tumours with of the phenotype of the family. partial LOH had a small region which included BRCA1 in common. Thus these studies strongly suggest that BRCA1 in International Collaborative Group on HNPCC familial tumours acts as a tumour-suppressor gene, and that loss of heterozygosity is greatly favoured to fully inactivate In 1989 a small group of experts on HNPCC from five it. In 1994 the gene sequence of BRCA1 was elucidated by countries met in Jerusalem to discuss the possibility ofsetting Mild et al. (1994). The overwhelming majority of alterations up an international collaborative group on HNPCC. In the in BRCA1 were subsequently found to be either frameshift same year these discussions were continued at an interna- or nonsense mutations that resulted in a truncated protein tional meeting on hereditary colorectal cancer in Kobe (Japan) product. Meera's group developed a rapid method to detect organized by Prof. J. Utsunomiya. The first formal meeting, mutations that lead to a truncated protein, the so-called which was organized by Meera and myself, was held in protein truncation test (Hogervorst et al. 1995). Amsterdam. During this meeting 30 representatives from eight countries reached agreement on the aims of the Inter- national Collaborative Group on HNPCC (ICG-HNPCC). Meera Khan left behind a huge scientific inheritance, with Discussions throughout the meeting focussed on the need to over 250 original publications lying between his first define minimum criteria for the identification of I-INPCC to scientific publication in the Journal of Heredity in 1960 and provide a basis for uniformity in collaborative studies. The his last in Nature Genetics in 1998. Meera was convinced group agreed that the following minimum criteria for the that the applied sciences cannot survive without the basic recruitment of families for collaborative studies should be met: sciences. In 1971 he stated that 'the diminishing support and (a) at least three relatives should have histologically verified the growing disinterest of the public and certain govern- colorectal cancer, one of whom was a first-degree relative of ments towards basic sciences--in an overenthusiastic the other two, and familial adenomatous polyposis should be attempt at boosting the applied sciences--may gradually excluded; (b) at least two generations should be affected; (c) jeopardise the applied sciences themselves'. Instead, with colorectal cancer should have been diagnosed in one of the his background as a medical doctor, he always stressed the relatives before the age of 50 years (Vasen et al. 1991). These importance of an intensive interaction between research criteria are currently applied all over the world. As vice laboratory and clinicians. This was also reflected in the chairman of the ICG, Meera played a major role in develop- great interest he showed in the clinical studies performed by ing these criteria and in promoting collaborative studies. the members of his group.

68 Journal of Genetics, Vol. 78, No. 1, April 1999 Meera Khan

Meera Khan played an important role in the organization Bronner C. E., Baker S. M., Morrison P. T., Warren G., Smith L. of research at national and international levels. He and five G., Lescoe M. K. et al. 1994 Mutation in the DNA mismatch other human gene explorers and mappers set up the first repair gene homologue hMLH1 is associated with HNPCC. Nature 368, 258-261. International Guidelines for naming human genes. He was Cornelis R. S., Devilee P., van Vliet M., Kuipers-Dijkshoorn N., an executive chairman of chromosome committees at six Kersenmaeker A., Bardoel A., Meera Khan P. and Cornelisse C. consecutive international human gene mapping workshops. J. 1993 Allele loss patterns on chromosome 17q in 109 breast He was a joint organizer of a number of international work- carcinomas indicate at least two distinct target regions. Oncogene 8, 781-785. shops, symposia and conferences in the areas of isoen- Cornelis R. S., Neuhausen S. L., Johansson O., Arason A., Kelsell zymes, purine and pyrimidine metabolism, gene mapping D., Ponder B. A. et al. 1995 High allele loss rate at 17q12-q21 in and hereditary cancer. He was among the founding breast and ovarian tumours from BRCAl-linked families. members of HUGO, the international human genome Genes, Chromosomes and Cancer 15, 203-210. organization, and a member of scientific societies, including Dronamraju K. R. and Meera Khan P. 1960 Inbreeding in Andhra Pradesh. J. Hered. 51, 239-242. human genetics societies of America, Europe, The Nether- Easton D. E, Bishop D. T., Ford D., Crockford G. P. and the Breast lands and India. He actively supported the establishment of Cancer Linkage Consortium 1993 Genetic linkage analysis in several national and international collaborative groups, such familial breast and ovarian cancer: Results from 214 families. as EUROFAP and ICG-HNPCC. He served on the editorial Am. J. Hum. Genet. 52, 678-701. board of Genomics, Anticancer Research, Cytogenetics and Eccles D. M., van der Luijt R. B., Breukel C., Bullman H., Bunyan Cell Genetics, In Vivo, and Journal of Genetics. D., Fisher A. et al. 1996 Hereditary desmoid disease due to a frameshift mutation at codon 1924 of the APC gene. Am. J. Moreover, he left behind a strong colorectal cancer Hum. Genet. 59, 1193-1201 genetics group in Leiden under the leadership of Riccardo Ephrussi B. and Weiss M. C. 1965 Interspecific hybridization of Fodde, which will undoubtedly continue his successful somatic cells. Proc. Natl. Acad. Sci. USA 53, 1040-1042. research lines. Perhaps even more important is the fact that Fishel R., Lescoe M. K., Rat M. R. S., Copeland N. G., Jenkins N. he left behind a group of young enthusiastic scientists to A., Garber J., Kane M. and Kolodner R. 1993 The human mutator gene homolog MSH2 and its association with HNPCC. whom he had taught the art of science. Because of his high Cell 75, 1027-1038. standards, Meera was not always easy on his students. He Fodde R., Edelmann W., Yang K., van Leeuwen C., Carlson C., taught the members of his human genetics team* in The Renault B. et al. 1994 A targeted chain-termination in the mouse Netherlands, in the same way as he himself had been taught Apc gene results in multiple intestinal tumours. Proc. Natl. Acad. Sci. USA 91, 8969-8973. by Haldane, 'to search for, and discover new scientific Groden J., Thliveris A., Samowitz W., Carlson M., Gelbert L., truths and to spread old ones'. Likewise, he reminded them Albertsen H. et al. 1991 Identification and characterization of regularly of the principles of moral courage, scientific the familial adenomatous polyposis gene. Cell 66, 589-600. honesty, and intellectual integrity. His team is inexpressibly Hall J., Lee M. K., Newman B., Morrow J. E., Anderson L. A., proud to have been taught by him, and will continue to Huey B. and King M.-C. 1990 Linkage of early-onset breast cancer to chromosome 17q21. Science 250, 1684-1689. implement the principles which started with Haldane, later Harris H. and Watkins J. E 1965 Hybrid cells derived from mouse became Meera Khan's, and have now become their own. and man: artificial heterokaryons of mammalian cells from different species. Nature 205, 640--646. Herrera L., Kakati S., Gibas L., Pietrzak E. and Sandberg A. A. References 1986 Gardner syndrome in a man with an interstitial deletion of 5q. Am. J. Med. Genet. 25, 473--476. Barski G., Sorieul S. and Comefert E 1960 Production dans des Hogervorst E B. L., Comelis R. S., Bout M., van Vliet M., Oosterwijk cultures in vitro de deux souches cellulaires en association, de J. C., Olmer R. et al. 1995 Rapid detection of BRCA1 mutations celhiles de caractere 'hybride'. C. R. Acad. Sci. 251, 1825. by the protein truncation test. Nature Genet. 10, 208-212. Bodmer W. F., Bailey C. J., Bodmer J., Bussey H. J., Ellis A., Kinzler K. W., Nilbert M. C., Su L. K., Vogelstein B., Bryan T. M., Gorman P. et al. 1987 Localization of the gene for familial Levy D. B. et al. 1991 Identification of FAP locus genes from adenomatous polyposis on chromosome 5. Nature 328, 614-616. chromosome 5q21. Science 253, 661-665. Leach E S., Nicolaides N. C., Papadopoulos N., Lin B., Jen J., Parsons R. et al. 1993 Mutations of a MutS homolog in HNPCC. Cell 75, 1215-1235. * The members of his team were Dr C. Tops and Dr R. van der Leppert M., Dobbs M., Scambler P., O'Counell P., Nakamura Y., Luijt, who conducted excellent studies on FAP presented as two Stauffer D. et al. 1987 The gene for familial polyposis coli maps theses in 1996; Ir J. Wijnen, who worked for Meera Khan for 20 to the long ann of chromosome 5. Science 238, 1411-1413. years and was inspired by him to write a thesis on HNPCC; Dr F.H. Lindblom A., Tannergard S., Werelius B. and Nordenskjold M. Menko, clinical geneticist at the Department of Clinical Genetics, 1993 Genetic mapping of a second locus predisposing to Free University of Amsterdam, who wrote a thesis on familial HNPCC. Nature Genet. 5, 279-282. benign hypercalcaemia with Meera Khan as referent, and over the Littlefield J. W. 1964 Selection of hybrids from matings of fibro- last decade has closely collaborated on studies of FAP and blasts in vitro and their presumed recombinants. Science 145, HNPCC; and Dr H.EA. Vasen, internist at the Department of 709-710. Gastroenterology, Leiden University Medical Centre, and medical Meera Khan P. 1971 Enzyme studies in the interspecific somatic director of the Netherlands Hereditary Cancer Registry, who cell hybrids with special references to the mapping of the human enjoyed a very close and successful collaboration with Meera X-chromosome. Ph.D. thesis, University of Leiden, Leiden, The Khan for almost 20 years. Netherlands.

Journal of Genetics, Vol. 78, No: 1, April 1999 69 H. E A. Vasen

Meera Khan R 1993 Some of my reminiscences of Professor J. B. of familial adenomatous polyposis by bridging DNA-markers. S. Haldane. Bionature 13, 95-104. Lancet 11, 1361-1363. Meera Khan R, Westerveld A., Grzeschik K. H., Deys B. E, Garson van der Luijt R., Meera Khan P., Vasen H., van Leeuwen C., Tops O. M. and Siniscalco M. 1971 X-Linkage of human phospho- C., Roest R, den Dunnen J. and Fodde R. 1994 Rapid detection glycerate kinase confirmed in man-mouse and man-Chinese of translation terminating mutations at the APC gene by direct hamster somatic cell hybrids. Am. J. Hum. Genet. 23, 614--623. protein truncation test. Genomics 20, 1-4. Miki Y., Swensen J., ~hattuck-Eidens D., Futreal R A., Harshman van der Lnijt R. B., Meera Khan P., Vasen H. E A., Breukel C., K., Tavtigian S., Liu Q. et al. 1994 A strong candidate for the Tops C. M. J., Scott R. J. and Fodde R. 1997 Germline mutations breast and ovarian cancer susceptibility gene BRCAI. Science in the 3 ~ part of the APC exon 15 do not result in truncated 266, 66-71. proteins and are associated with attenuated adenomatous Moser A. R., Pitot H. C. and Dove W. E 1990 A dominant muta- polyposis. Hum. Genet. 98, 727-734. tion that predisposes to multiple intestinal neoplasia in the Vasen H. E A., Mecklin J.-P., Meera Khan P. and Lynch H. T. 1991 mouse. Science 247, 322-324. The international collaborative group on HNPCC. Dis. Colon Newman B., Austin M. A., Lee M. and King M.-C. 1988 Rectum 34, 424-425. Inheritance of human breast cancer: evidence for autosomal Vasen H. F. A., van der Luijt R. B., Slors J. F. M., Buskens E., de dominant transmission in high risk families. Proc. Natl. Acad. Ruiter P., Basten C. G. et al. 1996 Molecular genetic tests as a Sci USA 85, 3044-3048. guide to surgical management of familial adenomatous Oshima M., Oshima H., Kitagawa K., Kobayashi M., Itakttra C. polyposis. Lancet 348, 433-435. and Taketo M. 1995 Loss of Apc heterozygosity and abnormal Weiss M. C. and Green H. 1967 Httman-mouse hybrid cell tissue building in nascent intestinal polyps in mice carrying a lines containing partial complements of human chromosomes truncated Apc gene. Proc. Natl. Acad. Sci. USA 92, 4482--4486. and functioning human genes. Proc. Natl. Acad. Sci. USA 58, Papadopoulos N., Nicolaides N. C., Wei Y., Ruben S. M., Carter K. 1104-111t. C., Rosen C. A. et al. 1994 Mutations of a mutL homolog in Westerveld A. and Meera Khan P. 1972 Evidence for linkage HNPCC. Science 262, 1625-1629. between human loci for 6-phosphogluconate dehydrogenase and Peltomaki P., Aaltonen L. A., Sistonen P., Pylkkanen L., Mecklin J. phosphoglucomutase, in man-Chinese hamster somatic cell E, Jarvinen H. et al. 1993 Genetic mapping of a locus hybrids. Nature 236, 30-32. predisposing to human colorectal cancer. Science 260, 810-812. Wijnen J., Vasen H., Meera Khan P., Menko E H., van der Klift H., Ruddle E H., Chapman V. M., Ricciuti E, Murnane M., Klebe R. van den Broek M. et al. 1995 Seven new mutations in hMSH2 and Meera Khan R 1971 Linkage relationships of seventeen identified by denaturing gradient gel electrophoresis (DGGE). human gene loci as determined by man-mouse somatic cell Am. J. Hum. Genet. 56, 1060-1066. hybrids. Nature 232, 69-73. Wijnen 1, Meera Khan P., Vasen H., Menko E, van der Klift H., Scott R. J., van der Luijt R. B., Spycher M., Mary J. L., Muller A., van den Brock M. et al. 1996 Majority of hMLH1 mutations Hoppeler T. et al. 1995 Novel germline APC gene mutation in a responsible for HNPCC cluster at the exonic region 15-16. Am. large familial adenornatous polyposis kindred displaying vari- J. Hum. Genet. 61, 329-335. able phenotypes. Gut 36, 731-736. Wijnen J., van der Klift H., Vasen H., Meera Khan P., Menko F, Smits R., van der Houven-van Oordt W., Luz A., Zurcher C., Tops C., Meyers-Heijboer A., Lindhout D.M., Moller P. and Jagmohan-Changur S., Brenkel C., Meera Khan R and Fodde R. Fodde R. 1998a hMSH2 genomic deletions are a frequent cause 1998 Apc1638N: a mouse model for familial adenomatous of HNPCC. Nature Genet. 20, 326-328. polyposis-associated desmoid tumours and cutaneous cysts. Wijnen J., Vasen H. F. A., Meera Khan P., Zwinderman A. H., van Gastroenterology 114, 1-10. der Klift H., Mulder A. et al. 1998b Clinical findings with Tops C. M. J., Wijnen J. Th., Griffioeu G., van Leeuwen I. S., Vasen implications for genetic testing in families with clustering of H. E, den Harstog J. et al. 1989 Presymptomatic diagnosis colorectal cancer. N. EngL J. Med. 339, 511-518.

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