Leukemia (2001) 15, 1582–1588  2001 Nature Publishing Group All rights reserved 0887-6924/01 $15.00 www.nature.com/leu Novel genomic imbalances and translocations involving c- in Burkitt’s lymphoma DB Zimonjic, C Keck-Waggoner and NC Popescu

Laboratory of Experimental Carcinogenesis, Division of Basic Sciences, National Cancer Institute, NIH, Bethesda, MD, USA

In this study, CA46 and ST486, two Epstein–Barr (EBV) nega- involving the c-myc on chromosome 8q24 to any of tive lines derived from sporadic BL, were analyzed by multi- the three immunoglobulin loci on 14q32, color spectral karyotyping, G-banding, fluorescence in situ 8 hybridization with single-copy gene probes, and comparative 2p11 or 22q11. Although all the translocations result in c- genomic hybridization (CGH). In addition to reciprocal myc gene deregulation, the position of the breakpoints may t(8;14)(q24;q32) translocation involving c-myc and IgH loci, we varyfrom case to case. The breakpoint in most common trans- identified a t(7;8;14)(q11.2;q24;q32) translocation in CA 46 cells location t(8;14) cluster within or near myc locus.9 In two BL and t(8;14;18)(q24;q32;q23) in ST486 cells. Both rearrange- cell lines, CA46 and ST486, the breakpoints involve an almost ments were not previously described in BL and resulted in identical site within the first intron of c-myc.10 In both lines, transposition of myc sequences in a new genomic configur- ation. Several DNA imbalances mapped by CGH at the same the first noncoding exon of the gene is retained on chromo- sites in both lines, may reflect recurrent genomic changes that some 8, while the coding sequences of the second and third are relevant to pathogenesis of BL. We tested the tumorigeni- exon are translocated to, and rearranged with different regions city of these lines by injecting cells intraperitoneally in SCID of the IgH locus on chromosome.10 mice. In two separate experiments, CA46 cells produced Even though CA46 and ST486 lines have been used to tumors 2 weeks after cell inoculation while ST486 cells induced clone and sequence the translocated myc gene in BL, their only one tumor after a long latency period. Partial duplication 10 of the long arm of involving variable bands but cytogenetic characterization was not reported. We analyzed always band 1q23 is the second most common alteration in BL these lines byseveral molecular cytogenetictechniques and and is known to be associated with aggressive tumors and found novel rearrangements involving c-myc gene and gen- poor prognosis. Duplication of the bands 1q23–24 commonly omic imbalances that maybe important to the pathogenesis observed in EBV-negative lines was identified only in highly of this malignancy. tumorigenic CA46 cells suggesting that this region harbor gene(s) associated with tumor cell invasiveness. Leukemia (2001) 15, 1582–1588. Materials and methods Keywords: Burkitt’s lymphoma; chromosome translocation; c-myc; comparative genomic hybridization; fluorescence in situ hybridiz- CA46 and ST486 cell lines derived from sporadic BL (ATCC, ation; spectral karyotyping Rockville, MD, USA) were cultivated in RPMI 1640 medium supplemented with 10% fetal bovine serum and antibiotics. Both lines are Epstein–Barr virus (EBV) nuclear antigen-nega- Introduction tive. Chromosomes were prepared using standard hypotonic KCl and methanol/acetic acid fixation procedures. A significant number of leukemias and lymphomas have spe- For CGH, DNA was isolated from cultured cells according cific reciprocal chromosomal translocations.1,2 Reciprocal to standard phenol-extraction protocols. Genomic DNA from translocations maylead to activation of proto-oncogenes or cell lines and from normal cells, were labeled bynick- generate new oncogenic chimeric genes. As both oncogene translation with biotin (Bio-16-dUTP, Boehringer Mannheim, products and gene fusion are often transcriptional Mannheim, Germany) and digoxigenin (Dig-11-dUTP, Boeh- factors, the disruption of transcription control might be a criti- ringer Mannheim), respectively, and hybridized to chromo- cal and etiologicallyrelevant alteration in the development of somes prepared from normal lymphocyte cultures. The orig- certain forms of neoplasia. In addition, fusion proteins are inal CGH protocol with minor modification as previously unique tumor antigens and are potential targets for therapy described in detail, was employed.6 design.2–5 SKY analysis was performed as previously described.11 Because recurrent chromosomal translocations provide Chromosome probe cocktail labeled bySpectrum Orange, cytogenetic and molecular markers for the diagnosis, prog- Texas Red, CY5, Spectrum Green, and Cy5.5, was denatured nosis and detection of minimal residual disease, theyhave and hybridized on denatured target slides. Visualization for been analyzed by a variety of molecular and conventional biotin- and digoxigenin-labeled of the probe-cocktail cytogenetic procedures. The advancements in molecular cyto- was carried out using avidin-Cy5 (Amersham, Piscataway, NJ, genetics through the development of FISH-based protocols for USA) and antidigoxigenin-Cy5.5 (Sigma, St Louis, gene localization, global detection of genomic imbalances, MO, USA). An interferogram for each metaphase was gener- and multicolor visualization of structural chromosome ated using SD200 Spectracube (Applied Spectral Imaging, changes, have propelled the analysis of cancer cells to an Carlsbad, CA, USA) mounted on Zeiss Axioscope II fluor- unprecedented level of resolution.6,7 escent microscope equipped with custom-made optical filter Characteristic for Burkitt’s lymphoma (BL) are translocations (Chroma Technology, Brattleboro, VT, USA), and spectral information, upon recoverybyFourier transformation, was used to produce multicolor digital image with red, green and blue colors assigned to certain ranges of recorded spectrum. Correspondence: NC Popescu, National Cancer Institute, 37 Convent Drive MSC 4255, Bethesda, MD 20892-4255, USA; Fax: 301 496 Further analysis and classification were performed in SKY 0734 View 1. 5 karyotyping software (Applied Spectral Imaging) Received 7 March 2001; accepted 19 July2001 using a Windows NT Workstation. Genetic abnormalities in Burkitt’s lymphoma DB Zimonjic et al 1583 Biotin- and digoxigenin-labeled chromosomes 8 and 14 allowed an unequivocal identification of all structural painting and telomeric probes, chromosome-arm probes for rearrangements, including their precise derivation, as well as chromosome 1, a genomic myc probe (Oncor, Gaithersburg, the localization of breakpoints and genomic imbalances. MD, USA) as well as YAC probes for regions 1q21-q25 were SKY results are based on 20 complete multicolor used for FISH. Detection of the hybridization signal, digital which include inverted DAPI banding for each of the meta- image acquisition, and analysis were carried out as pre- phases. G-banding analysis was based on 10 separate viouslydescribed. 12 trypsin/Giemsa-banded karyotypes in each line. Three clonal Cells derived from each line were tested for tumorigenicity subpopulations were observed in CA46 line. The largest sub- in SCID mice (NCI Breeding Facility, Bethesda, MD, USA). population of approximately50% of the cells, had reciprocal Each group of five animals, was injected intraperitoneallywith t(8;14)(q24;q32) translocation involving c-myc and IgH loci a 0.5 ml of suspension in complete medium containing 1 × (Figure 1a), an intrachromosomal rearrangement of chromo- 106 and 2 × 106 cells. Animals were examined weeklyfor some 1, and in the majorityof cells, trisomy16. A fraction of tumor growth. For histopathologic examination pieces of these cells had trisomy7 and most likelywere the progenitor tumor tissue were fixed in formalin buffer, embedded in paraf- of two other subpopulations carrying secondary translocations fin, cut, deparaffinized and stained with hematoxylin and t(7;8;14)(q11.2;q24;q32) and t(7;13)(q11;p11), both involving eosin. (Figure 1b and c). These alterations resulted in loss of chromosome 7 material. In balanced t(8;14) translo- cation, the segment from of approximately Results 150 Kb13 translocated on was not visible by SKY or bypainting with chromosome 14 probe, but was The profile of cytogenetic alterations in CA46 and ST468 lines detected byFISH with chromosome 14 telomeric probe was determined bySKY, G-banding, CGH and FISH, shortly (Figure 2a). Cells with this , after hybridization with after the cells were received from ATCC, as well as after exten- myc genomic probe, had three signals on chromosome 8, sive subculturing. A combined molecular cytogenetic analysis der(8) and der(14) (Figure 2b). Secondaryt(7;814) translo-

Figure 1 Spectral karyotyping (SKY) analysis of Burkitt’s lymphoma cell lines CA46 and ST486. (a) SKY karyotype of the predominant cell subpopulation from CA46 line. All of these cells have reciprocal t(8;14) translocation and alteration of chromosome 1. The segment from chromosome 14 translocated on chromosome 8 was not detected by SKY. (b) SKY karyotype of a second cell subpopulation from the CA46 line having a secondary t(7;8;14) translocation. (c) SKY karyotype of a third cell subpopulation from the CA46 line having a secondary t(7;13) translocation. (d) SKY karyoytpe of the ST486 cell line. As in CA46 cells the reciprocal t(8;14) translocations was not fully detected by SKY. Other abnormalities in these lines are two complex translocations: t(1;16) and t(8;14;18).

Leukemia Genetic abnormalities in Burkitt’s lymphoma DB Zimonjic et al 1584

Figure 2 Fluorescence in situ hybridization (FISH) analysis of chromosomal translocations in CA46 and ST486 cell lines. (a) Metaphase from CA46 cell line carrying balanced t(8;14) translocation after FISH with 14-qter specific probe. Double fluorescent signals on the distal ends of one chromosome 14 and on der(8) are pointed byarrows. (b) Metaphase from CA46 cells exhibiting t(8;14) translocation, hybridizedwith c- myc probe. Signals for myc gene are on chromosome 8, der(8), and der(14) (arrows). (c) Metaphase from CA46 cells exhibiting a secondary t(7;8;14) translocation, hybridized with c-myc probe. Signals for myc gene are on chromosome 8, der(8), and der(7) (arrows). (d) Metaphase from ST486 having two translocations involving c-myc gene. Signals, after hybridization with myc probe, are on chromosome 8, der(8), der(14) and der(18) (arrows).

Figure 3 Characterization of chromosome 1 amplification bySKY and FISH with chromosome-arm painting probes and band-specific YAC probes in BL lines. Far right panel shows the ideograms of chromosomes 1 and the number of YAC signal detected at each site and in each homologue. (a) Fluorescent signals observed after hybridization with band-specific YAC probes spanning region 1q21-q25, demonstrate dupli- cation and inversion of region 1q21-q24 in CA46 cells. (b) The same approach revealed triplication of band 1q21 in rearranged derivative(16) chromosome in ST 486 cells, but lack of amplification of other bands probed.

cation was discernible onlybySKY and derived from t(8;14) plex intrachromosomal rearrangement. In order to gain insight in which the telomeric region of the der(14) carrying myc into the nature and the mechanism involved in this abnor- sequences fused with part of chromosome 7 (Figure 1c). These mality, FISH with specific probes was used. Painting with cells had three FISH signals for myc gene located on chromo- chromosome-arm probes showed that a piece from 1q was some 8, der(8), and on der(14) at the junction of chromosomes inserted into 1p, whereas FISH with YAC probes for bands 7 and 8 (Figure 2c). 1q21, 1q23, 1q24 and 1q25 revealed that the abnormality Abnormalityof chromosome 1 was observed in all three consisted of duplication followed byinversion and insertion subpopulations. SKY and G-banding analysis indicated a com- of region 1q11–24 into 1p (Figure 1a, b, c and Figure 3a).

Leukemia Genetic abnormalities in Burkitt’s lymphoma DB Zimonjic et al 1585 Cells from CA46 line had three signals for YACs 1q21, q23 somes 3, 4, 8, 9, 11, 13, 18 and Y were identified in both and q24, respectively, on both arms of the rearranged 1 lines (Table 1). (Figure 3a). Thus this anomalyis defined as der(1) inv To correlate the profile of genetic alterations with tumori- dup(q11–24). genicity, 1 × 106 and 2 × 106 cells from each line were ST486 line had a uniform karyotype with reciprocal translo- injected into the abdominal cavityof SCID mice. In two separ- cation t(8;14)(q24;q32) and a t(8;14;18)(q24;q32;q23) translo- ate experiments, onlyCA46 cells produced progressively cation involving the telomeric region of the der(14) carrying growing tumors 2–3 weeks after inoculation. Histologically, 8q material and distal segment of the long arm of chromo- these tumors were consistent with a diffuse noncleaved cell some 18 (Figure 1d). As a result of these rearrangements, myc lymphoma having a characteristic starry-sky pattern and dif- sequences were dispersed at four sites on chromosome 8, fuselyinfiltrating the tissue. The tumor cells were monomor- der(8), der(14) and der(18) (Figure 2d). Other consistent phic and exhibited a high mitotic rate. Onlyone tumor from changes were a rearrangement of chromosomes 1 and 16 a total of 10 animals inoculated with ST486 cells was depicted bySKY as t(1;16), a t(15;15)(p13;q21) translocation observed 40 days after cell inoculation (Table 2). and trisomy7 (Figure 1d). The rearranged derivative 16 chro- Cells derived from a tumor developed in SCID mice after mosome stained dark on trypsin G-banded preparations the inoculation of CA46 were also examined at the earliest (Figure 4) and bright on DAPI stained chromosomes (Figure passages in cultures. All three populations were represented 3b). FISH analysis with YAC probes for bands 1q21, q23, q24 in similar proportion and had an identical karyotype as the and q25 showed that this rearranged derivative(16) chromo- inoculated cells. some contains a tandem triplication of region 1q21 resulting in a total of five copies of this region and no duplication of bands 1q23, q24 and q25 (Figure 3b). Discussion CGH profiles obtained byaveraging a minimum of 25 indi- vidual metaphase profiles for each line is shown in Figure 5. This combined molecular cytogenetic analysis of BL-derived Duplicate experiments resulted in similar average profiles. cell lines demonstrates new rearrangements of myc gene, Due to the variabilityof repetitive DNA sequences, the cen- whose deregulation is critical to the development of this tromeric and heterochromatic chromosome regions were malignancy, as well as DNA copy-number imbalances that excluded from analysis. Several conspicuous telomeric imbal- maybe important genetic changes in pathogenesis of BL. ances, smaller than a band of an average size, even though Translocations t(7;8;14) and t(8;14;18) are new rearrange- common to both lines, were not included in the total list of ments involving myc gene that maybe relevant to the imbalances shown in Table 1. initiation and progression of BL. The complete derivation of The average ratio profile of both lines is shown in Figure 5 such complex and hidden abnormalities bySKY, illustrates the and positional mapping of imbalances at specific regions is power of this technique to detect chomosome changes in can- presented in Table 1. Overrepresentations on chromosomes cer cells.14 Translocation t(7;8;14) in CA 46 cells which 1, 7, 16, 19, 22 and X, and underrepresentations on chromo- derived from the reciprocal t(8:14) translocation through

Figure 4 G-band karyotype from a ST486 cell arranged according to spectral karyotyping results. The chromosome banding allows precise localization of the breakpoints in abnormal chromosomes.

Leukemia Genetic abnormalities in Burkitt’s lymphoma DB Zimonjic et al 1586

Figure 5 Comparative genomic hybridization profiles of CA46 (a) and ST486 (b) cell lines.

breakage and reunion with a third chromosome, is likelyto CA46 and ST486 cells. ByFISH, three double symmetrical be a secondaryalteration. Its occurrence was accompanied fluorescent signals, and one to four extrachromosomal single bypartial loss of chromosome 7 and loss of a copyof chromo- signals, were detected in more than 85% of the cells from some 16. On the other hand, t(8;14;18) translocation in ST486 both CA46 and ST486 lines. It was concluded that amplified cells, mayhave occurred concomitantlywith t(8:14) through copies of the translocated myc exons are associated with a three-chromosome rearrangement consisting of breakage chromosomal DNA onlyin ST486 cells and persistent extra- followed bypartial duplication and transposition of 14q32 to chromosomal elements are present in both lines.16 The pres- . Region 18q22–23 maybe a recurrent site ence of amplified myc exons is consistent with our FISH for breakage and reunion in a subset of BL, as in another case detection of additional double signals on der t(8;14;18) to a having a duplicated t(2;8) translocation which also had a total of four copies in ST486 line. Notably, the CGH profile translocation t(2;18) with breakpoint at 18q22.15 Translo- shows DNA overrepresentation confined to 8q24. In contrast, cation t(8;14;18) in ST486 cells, placed IGH and myc genes we observed single spots outside chromosomes, inherent of in a new genomic configuration. This event, however, did not the hybridization background, only in rare metaphases in both alter the level of myc transcription, which is similar in both lines. Thus, our FISH observations with these lines are not lines.10 In a previous report using hybridization of size-frac- compatible with the presence of extrachromosomal elements. tionated DNA and FISH with myc cDNA probe, chromosomal Onlytwo cases of BL have been examined byCGH: in one and extrachromosomal amplified elements were detected in case, a high level amplification of 2p23-p25 involving n-myc

Leukemia Genetic abnormalities in Burkitt’s lymphoma DB Zimonjic et al 1587 Table 1 Genetic abnormalities detected byCGH in CA46 and cells. In hematological malignancies, secondaryalterations ST486 Burkitt’s lymphoma cell lines are frequentlyassociated with a more aggressive phenotype and poor prognosis.21–23 It is tempting to speculate that the Gains Losses occurrence of such a secondarychange mayexplain the high tumorigenic potential of CA46 cells. Two observations, how- CA46 ST486 CA46 ST486 ever, argue against this possibility. First, the subpopulation carrying the secondary t(7;8;14) translocation was minor com- 1p35 1p36.2–p34.2 1q43 pared to the others and remained the same after extensive sub- 1p13–q24 1p13–q22 2q21–q32 5q11.2 3p26 3p26–p25 culturing. Second, all three subpopulations were represented 7q11.1–q22 7p22–q22 3p14–p12 in similar proportions in tumors developed in SCID mice. 7q31–q36 3q28 Alterations of chromosome 1q maybe the most important 8q24.1 4q13 to the BL cells behavior in vivo. It has been known for some 9q11–q21 9q34 4q22–q32 time from conventional cytogenetic studies, that partial dupli- 14p12 4q34 4q34 cation 1q is the second most frequent change in BL and acute 14q23–q32 5p14 21,24–28 15p13–p11.1 5q14–q22 lymphoblastic leukemia (ALL) type L3 Burkitt-like. 15q21–q25 6p21 Duplication 1q involves variable bands but always band 16p12–p11.2 6q11–q14 1q23. This abnormalitywas considered the functional equiv- 16p13.1–q23 16q21–q24 6q16 alent of the EBV infection as it occurs in the absence of EBV 18p11.2–q11.2 6q22 infection and involve bands 1q23–24.28,29 19p13.3–p12 19p13.3–p12 8p23 8p23 Although both CA46 and ST486 cells exhibit alteration 1q, 19p12–q13.2 19q12–q13.2 9p23 9p24–p21 22p12 22 10p15 our combined CGH, SKY, FISH and G-banding analysis con- Xp11.2–Xq13 X 11q14 clusivelydemonstrates that onlyhighlytumorigenic CA46 11q24 11q24 cells had duplication 1q23-q24. Remarkably, the length of 12q21 DNA copy-number overrepresentation in CGH profile corre- 13q14–q31 sponded with the copy-number of YAC signals on 1q (Figures 13q31–q34 13q33 4 and 5). This is an important observation since a strong 18p11.3 18p11.3 18q23 18q21–23 association between partial duplication of 1q and poor prog- 20p13 nosis was found in 148 cases of BL/ALL-L-326. Furthermore, YYcell lines with 1q alterations are highlyor moderatelytumori- genic.30 This maypartiallyaccount for CA46 cell aggressive behavior in vivo. ST486 cells had two normal copies of chro- mosome 1 and a triplication of the region 1q21 as a part of Table 2 Tumorigenicityof CA46 and ST486 Burkitt’s lymphoma a rearrangement involving chromosomes 1 and 16. Therefore, cell lines in SCID mice in ST486 cells chromosome 1 alteration consists of multipli- cation (five copies) of the region 1q21. While alterations 1q Cell No. of Latency No. of tumors/ maybe important in the initial stages of BL development in line cells (days) No. of inoculations the absence of EBV infection, duplication of bands q23-q24 maybe critical during progression and the acquisition of an CA46 1 × 106 21 9/10 invasive tumor phenotype. The SKI, TRK and S100 tumor pro- × 6 2 10 14 10/10 gression and metastasis genes, as well as BLC9 gene cloned ST486 1 × 106 — 0/10 from a translocation 1;14 in B cell acute lymphoblastic leuke- 2 × 106 40 1/10 mia are localized within the region of 1q duplication.31–34 Future investigations are warranted to see if anyof these gene or other genes are altered in BL due to partial 1q duplications. gene was detected,17 and in the second one, derived from a patient seropositive for HIV, DNA copy-number gains in five, Acknowledgements and losses in two chromosomal regions were identified.18 CA46 and ST486 lines have a high incidence of chromosomal We thank Dr Douglas Kingma from the Laboratoryof Pathol- gains and losses. The detection of common genomic changes ogy, National Cancer Institute, Bethesda, Maryland, for histo- suggests that BL has a distinct, nonrandom pattern of DNA logical diagnosis of the tumors. copy-number alterations. There was a remarkable correspon- dence between SKY and CGH profile, and structural alter- ations show once more the usefulness of combined analysis References in detecting genomic changes in cancer cells. The difference in tumorigenic potential of these cell lines 1 Mitelman F, Mertens F, Johansson B. A breakpoint map of recur- rent chromosomal rearrangements in human neoplasia. Nat Genet was striking and their use mayserve as a model for studying 1997; 15: 417–474. genetic changes and genes involved in tumorigenicity. A ser- 2 Nowell P, Dalla-Favera R, Finan J, Erikson J, Croce C. Chromo- ies of recent studies with solid tumors showed that aggressive some translocations, immunoglobulin genes, and neoplasia. In: tumors have a higher number of copyalterations per case. 19 RowleyJD, Ultmann JE (eds). Chromosomes and Cancer: from Along this line, the degree of tumorigenicityof several breast Molecules to Man. Academic Press: New York, 1983, pp 165– carcinoma cell lines correlated with the extent of genomic 181. 20 3 Bishop JM. The molecular genetics of cancer. Science 1987; 235: changes. This is not the case with these BL lines, as CA 46 305–311. cells which were aggressive in vivo have a lower incidence 4 ClearyML. Oncogenic conversion of transcription factors by of genomic imbalances than the weak tumorigenic ST486 chromosomal translocations. Cell 1991; 66: 619–622.

Leukemia Genetic abnormalities in Burkitt’s lymphoma DB Zimonjic et al 1588 5 Rabbitts TH. Chromosomal translocations in human cancer. Nat- nancy potential in solid human tumors: a phenotype/genotype ure 1994; 372: 143–149. correlation. Genes Chromos Cancer 1999; 25: 195–204. 6 Kallioniemi A, Kallioniemi OP, Sudar D, Rutovitz D, GrayJW, 20 Zimonjic DB, Keck-Waggoner CL, Yuan BZ, Kraus MH, Popescu Waldman F, Pinkel D. Comparative genomic hybridization for NC. Profile of genetic alterations and tumorigenicityof human molecular cytogenetic analysis of solid tumors. Science 1992; breast cancer cells. Int J Oncol 2000; 16: 221–230. 258: 818–821. 21 Bloomfield CD, Arthur DC, Frizzera G, Levine EG, Peterson BA, 7 Schro¨ck E, du Manoir S, Veldman T, Schoell B, Wienberg J, Fergu- Gajl-Peczalska KJ. Nonrandom chromosome abnormalities in son-Smith MA, Ning Y, Ledbetter DH, Bar-Am I, Soenksen D, Gar- lymphoma. Cancer Res 1983; 43: 2975–2984. ini Y, Ried, T. Multicolor spectral karyotyping of human chromo- 22 Sandberg AA, Chen Z. Cancer and molecular gen- somes. Science 1996; 273: 494–497. etics: clinical implications. Int J Oncol 1995; 7: 1241–1251. 8 Dalla-Favera R, Bregni M, Erikson J, Patterson D, Gallo RC, Croce 23 Sheer D, Squire J. Clinical applications of genetic rearrangements CM. Human c-myc onc gene is located on the region of chromo- in cancer. Semin Cancer Biol 1996; 7: 25–32. some 8 that is translocated in cells. Proc Natl 24 Douglass EC, Magrath IT, Lee EC, Whang-Peng J. Cytogenetic Acad Sci USA 1982; 79: 7824–7827. studies in non-African Burkitt lymphoma. Blood 1980; 55:148– 9 Pelicci PG, Knowles DMD, Magrath I, Dalla-Favera R. Chromo- 155. somal breakpoints and structural alterations of the c-myc locus 25 Berger R, Le Coniat M, Derre J, Vecchione D. Secondarynonran- differ in endemic and sporadic forms of Burkitt lymphoma. Proc dom chromosomal abnormalities of band 13q34 in Burkitt lym- Natl Acad Sci USA 1986; 83: 2984–2988. phoma–leukemia. Genes Chromos Cancer 1989; 1: 115–118. 10 Showe LC, Ballantine M, Nishikura K, Erikson J, Kaji H, Croce 26 Kornblau SM, Goodacre A, Cabanillas F. Chromosomal abnor- CM. Cloning and sequencing of a c-myc oncogene in a Burkitt’s malities in adult non-endemic Burkitt’s lymphoma and leukemia: lymphoma cell line that is translocated to a germ line alpha switch 22 new reports and a review of 148 cases from the literature. region. Mol Cell Biol 1985; 5: 501–509. Hematol Oncol 1991; 9: 63–78. 11 Zimonjic DB, Pollock J, Westerfield P, Popescu NC, LeyJT. 27 Offit K, Jhanwar SC, Ladanyi M, Filippa DA, Chaganti RS. Cyto- Acquired, non-random chromosomal abnormlities associated with genetic analysis of 434 consecutively ascertained specimens of the development of acute promyelocitic leukemia in transgenic non-Hodgkin’s lymphoma: correlations between recurrent aber- mice. Proc Natl Acad Sci USA 2000; 97: 13306–13311. rations, histology, and exposure to cytotoxic treatment. Genes 12 Zimonjic DB, Rezanka L, DiPaolo JA, Popescu NC. Refined local- Chromos Cancer 1991; 3: 189–201. ization of the erbB-3 proto-oncogene bydirect visualization of 28 Polito P, Cilia AM, Gloghini A, Cozzi M, Perin T, De Paoli P, FISH signals on LUT-inverted and contrast-enhanced digital Gaidano G, Carbone A. High frequencyof EBV association with images of DAPI-banded chromosomes. Cancer Genet Cytogenet non-random abnormalities of the chromosome region 1q21–25 in 1995; 80: 100–102. AIDS-related Burkitt’s lymphoma-derived cell lines. Int J Cancer 13 Honjo T, Matsuda F. Immunoglobulin heavychain loci of mouse 1995; 61: 370–374. and human. In: Honjo T, Frederick W (eds). Immunoglobulin 29 Berger R, Bernheim A. Is there a functional equivalence between Genes, 2nd edn. Academic Press: London, 1995, 145–171. abnormalities of the long arm of chromosome 1 and the presence 14 Veldman T, Vignon C, Schrock E, RowleyJD, Ried T. Hidden of Epstein–Barr virus in continuous lines of Burkitt’s lymphoma? chromosome abnormalities in haematological malignancies CR Acad Sci III 1984; 298: 143–145. detected by multicolour spectral karyotyping. Nat Genet 1997; 15: 30 Gurtsevitch VE, O’Conor GT, Lenoir GM. Burkitt’s lymphoma cell 406–410. lines reveal different degrees of tumorigenicityin nude mice. Int 15 Vazquez-Mazariego Y, Cabello P, Garcia-Sagredo JM, Lopez- J Cancer 1988; 41: 87–95. Yarto A, Vallcorba I, Resino M, Munoz R, Perez I, Mayayo M, 31 Chaganti RS, Balazs I, Jhanwar SC, MurtyVV, Koduru PR, Grzes- Ferro MT. Burkitt lymphoma with a duplication of der(8)t(2;8). chik KH, Stavnezer E. The cellular homologue of the transforming Interpretation of a complex karyotype by chromosome painting. gene of SKV avian retrovirus maps to human chromosome region Cancer Genet Cytogenet 1994; 76: 136–139. 1q22-q24. Cytogenet Cell Genet 1986; 43: 181–186. 16 Khaira P, James CD, Leffak M. Amplification of the translocated 32 Morris CM, Hao QL, Heisterkamp N, Fitzgerald PH, Groffen J. c-myc genes in three Burkitt lymphoma cell lines. Gene 1998; Localization of the TRK proto-oncogene to human chromosome 211: 101–108. bands 1q23–1q24. Oncogene 1991; 6: 1093–1095. 17 Werner CA, Dohner H, Joos S, Trumper LH, Baudis M, Barth FE, 33 Engelkamp D, Schafer BW, Mattei MG, Erne P, Heizmann CW. Ott G, Moller P, Bentz M. High-level DNA amplifications are Six S100 genes are clustered on human chromosome 1q21: identi- common genetic aberrations in B-cell neoplasms. Am J Pathol fication of two genes coding for the two previouslyunreported 1997; 151: 335–342. calcium-binding proteins S100D and S100E. Proc Natl Acad Sci 18 Zunino A, Viaggi S, Ottaggio L, Fronza G, Schenone A, Roncella USA 1993; 90: 6547–6551. S, Abbondandolo A. Chromosomal aberrations evaluated by 34 Willis TG, Zalcberg IR, Coignet LJ, Wlodarska I, Stul M, Jadayel CGH, FISH and GTG-banding in a case of AIDS-related Burkitt’s DM, Bastard C, Treleaven JG, CatovskyD, Silva ML, DyerMJ. lymphoma. Haematologica 2000; 85: 250–255. Molecular cloning of translocation t(1;14)(q21;q32) defines a 19 Ried T, Heselmeyer-Haddad K, Blegen H, Schrock E, Auer G. novel gene (BCL9) at chromosome 1q21. Blood 1998; 91: Genomic changes defining the genesis, progression, and malig- 1873–1881.

Leukemia