Malignant Transformation of Human Prostate Epithelial Cells by N-Nitroso-N-Methylurea

ICANCERRESEARCH57.576-580.February15.19971

Advances in Brief

Malignant Transformation of Human Prostate Epithelial Cells by N-nitroso-N-methylurea

Johng S. Rhim,' Sunji Jin, Mira Jung, Peter J. Thraves, Michael R. Kuettel, Mukta M. Webber, and Bharati Hukku

Laboratory of Biochemical Physiology, National Cancer institute, Building 567, Frederick@Maryland 21702 Ii. S. R., S. fl; Department of Radiation Medicine, Vincent T. Lombardi Cancer Center, Georgetown University School of Medicine, Washington, D.C. [M. J., P. 1. T., M. R. K.]; Departments of Medicine and Zoology. Michigan State University, East Lansing, Michigan 48824 [M. M. WI; and Cell Culture Laboratory, Childrenâ€˜sHospitalofMichigan, Detroit, Michigan 48201 [B. H.]

Abstract adulthumanprostateepitheliumandimmortalizedby HPV-18(5). Cellswere grownandmaintainedinserum-freekeratinocytemedium(Life Technologies, We report the malignant transformation of adult human prostate Inc.). epithelialcellsafter multiple exposurestothe chemicalcarcinogenN. Chemical Transformation Assay. One-day-old cultures of HPV-18 C-i nitroso-N.methylurea. Such transformants showed morphological alter (platedat1 X l0@cells/80-cm2flask)wereexposedtovariousdosesofNMU ations and anchorage-independent growth in soft agar and induced car for 1h.AfterNMUtreatment,thecultureswereallowedtogrowtoconfluence cinomaswhen transplanted into nudemice.No p53or ras mutations were with a changeof medium every 3 days, subsequentlypassagedto trypsin observed.Stepwisechromosomalchangesin the progressionto tumorige treatment,andexposedagainwith similar doses.Thecultureswerepassaged, nicity wereobserved.Lossofthe p arms ofchromosome8 (plO>pter) and exposedoncemoretoNMUwithsimilardoses,subculturedevery7â€”10days, chromosome10(plO>pter) and gain of the q arm of chromosome8 andobservedbiweeklyfor changesin morphologyor growthpattern. (qlO>qter) were only observedin the tumor outgrows. Thesefmdings ColonyFormationin SoftAgar. A cellsuspension(1x l0@cells/ml)in provide the first evidenceof malignant transformation of human prostate 5 ml of 0.35% Noble agarwith serum-free keratinocyte medium was overlaid epithelialcellsexposedtoa chemicalcarcinogen. into a60-mmdishcontaininga0.6%agarbase.Colonies>0.2 mmin diameter Introduction werecountedat21days. Tumorigenicity in Nude Mice. Cells (1 X l0@) in 0.2 ml of PBS were Prostate cancer is the most common malignancy and the second injecteds.c.into the mid-dorsalinterscapularregionof adult l29J nudemice leading cause of male cancer death in the United States (1). In 1996, and SCID mice to determine tumorigenicity. The nude mice were observed for 317,000 new caseswill be diagnosed, with over 40,000 deaths (1). It 6 monthsfortheappearanceoftumordevelopment. Rearand p53 Analysis. Exponentially dividing cells were labeled with is estimated that 1 of every 11 American men will eventually develop [35S]methionineat100 @CiJmifor4 h. The cell lysateswereimmunoprecipi prostate cancer. Compared with all other cancers, the incidence of tated with anti-p2l antibody (Y13-259; Oncogene Science) and analyzed by prostate cancer increasesmost rapidly with age (2, 3). The genetic and SDS-PAGE.RNA andgenomicDNAwereanalyzedtodeterminesequence environmental factors responsible for the high incidence of prostate modifications of cellular ras family (K-ms. H-ras, and N-ras) proteins, re cancers are largely unknown. In addition, unlike other major cancers spectively,in chemical-transformedandparentalprostatecell lines. The re such as breast, lung, and colon cancer, little is known at the molecular verse transcriptase reaction was performed with the following reagents in a andgeneticlevelsaboutprostatecancer(4). In vitro modelsof HPE2 final volumeof2O @.dofPCRbuffer(1 miji eachdeoxynucleotidetriphosphate, cells provide a practical approach to analyze the molecular and 1 unit of RNAs, 100 pmol random hexamer, 2 @lof RNA sample, and 200 genetic mechanismsunderlying prostate tumorigenesis. To our knowl units of Moloney mm-incleukemiavirus reversetranscriptase).Thesample edge, a chemical carcinogen-induced neoplastic transformation of was incubatedat 42Â°Cfor 60 mm, heatedat 95Â°Cfor 10 mm, and then HPE cell culture has not been described previously. followed by a quick chill on ice. The synthesizedeDNAandgenomicDNA We recentlyreportedtheimmortalizationof normaladultHPEcells wereusedastemplatesfor SSCP.Specificprimersfor the cellular ras genes by DNA transfection of the HPV-l8 genome and the subsequent and the p53 gene (exons 2â€”li) were obtained from Clontech (Palo Alto, CA). conversion of such nontumorigenic but immortalized cells (HPV-l8 Cytogenetic Analysis. Chromosome counts, ploidy distribution, and GTG bandedkaryotypeswerepreparedbystandardtechniques(6).The karyotypes C-l) into tumorigemccellsby the introductionof an activatedKi-ras weredescribedaccordingto theInternationalSystemof CytogeneticNomen oncogene (5). The availability of a HPE cell line that could undergo clature 1991. neoplastic conversion in responseto a ras oncogene led us to inquire whetherthis systemmightbeusefulin detectingchemicalcarcinogens Results for HPE cells. In the present study, we have demonstrated that HPV-18 C-l cells can be transformed to tumorigenicity in nude mice Transformation of HPV-18 C-i Cells by NMU. In the HPV-18 by treatment with the chemical carcinogen NMU. C-l line exposed three times to NMU, altered morphology was observedbythethird subcultures(4â€”5weeksaftertreatment);similar Materials and Methods changes were not observed in the control HPV-l8 C-l cells treated CellCultureandMedia. TheHPV-l8 C-l celllinewasusedatpassage26 with DMSO. Changeswere first observedin the cells treatedwith for thesetransformationstudies.Thiscell line wasderivedfrom nonmalignant NMU at 3 X 100 p.g/ml; however, alterations in the cells treated with NMU at 3 X 50 pg/mi becamemore pronouncedafter further sub

Received I 1/1/96, accepted 1/4/97. cultivation. The cells beganto pile up in focal areas,formed small The costsof publicationof this article were defrayedin part by the paymentof page projects, and released small cells from the foci (Fig. 1, Bâ€”D).These charges.Thisarticle mustthereforebeherebymarkedadvertisementinaccordancewith foci grew as islets that stained with Giemsa. The transformed cells 18 U.S.C. Section 1734 solely to indicate this fact.

I To whom requests for reprints should be addressed. Phone: (301) 846-1592; Fax: exhibited the typical polygonalarrangementof epithelial cells, even (301) 846-6863. after repeatedsubcultivation,but were smaller in size than the Un 2 The abbreviations used are: HPE, human prostate epithelial; HPV, human papillo mavirus; NMU, N-nitroso-N-methylurea;SSCP,single-strandconformationpolymor treatedHPV-l8 C-i cells. In contrast,the cellular morphologyof the phism. untreated HPV-18 C-i cells remained unchanged. They continued to 576

Fig. 1. HPE cells (HPV-18 C-l) treatedwith NMU for 1 h three times, followed by five subculturesin nutrientmedium.A, untreated(0.5% DMSO). B, 50 @g/mlNMU. C, 100 1zg/miNMU.D, 250,@g/miNMU.E,theinvivotumorinducedbyHPV-18C-IcellstreatedwithNMU(50p@g/ml)isapoorlydifferentiatedcarcinoma.

grow as nonoverlapping monolayer and exhibited typical polygonal agar with colony-forming efficiencies of 0.25, 0.31, and 0.35%, arrangement of epitheial cells (Fig. 1A). respectively, whereas the untreated cells did not grow in soft agar Characteristics of NMU-transformed HPV-18 C-i Lines. The (Table 1). NMU-transformed cells were further characterized by quantitative When athymic nude mice were inoculated s.c. with l0@NMU differencesin growth properties,suchas saturationdensityand soft transformedcells,theanimalsdevelopedtumorswithin 3â€”4monthsat agarcolony-formingefficiency. The saturationdensitiesof the NMU thesiteof inoculation(Table 1).TheNMU 3 X 50 @g/ml-treatedcells transformants were about two times higher than that of the untreated were highly tumorigenic. The mice inoculated with these transformed HPV-l8 C-i cells.Moreover,thechemicaltransformantsgrewin soft cellsdevelopedtumorswithin3 months.However,theNMU3 X 100 577

Table I Biological properties of HPV-18 C-I HPE cell line transformedby NMU Saturation density was measuredas the maximum number of cells obtained after initial plating with I X l0@cells/cm2 and then incubating at 36'C with growth medium changed every 3 days.

Tumorigenicity in nude mice Saturation densi@' Soft agar colony SCIDDMSOCell line (cells/cm x 10 ) formation (%) 129J (0.5%) 3.2 <0.01 0/4 NMU (3 x 50 p@g/ml) 5.1 0.35 3/4â€• NMU3/3NMU (3 x 50 @sg/ml)F' 5.2 0.40 2/3â€• 1/4NMU(3 X 100 jzg/ml) 5.5 0.31 1/4 1/3NMU(3 x 100 @zg/ml)F 5.3 0.32 2/3 0/4a (3 X 250 @eg/ml) 4/2 0.25 0/4

done.bND. Not analysis.(Tumors were reestablished in tissue culture and confirmed as human cells; their resemblance in the cells of origin was determined by karyological [email protected]/ml-treatedF. focus-derived chromosomesaftercells were less tumorigenic. They produced tumors chromosomes Y, 3, 7, 13, and 18 and gain of a copy of ofMicroscopic4 months after inoculation only in one of four athymic mice. 5 and 20 and minute-M4. Out of the missing normal copies M2-del(3)(p14),differentiatedexamination of sections of these tumors revealed poorly chromosomes, 3, 7, and 18 are involved in markers toInjection carcinoma (Fig. 1E) consistent with prostate cancer. Ml-del(7)(q2l), and M5-del?(18)(ql 1q23), respectively, leading qin of these cells into l29J nude mice and SCID mice resulted the loss of part of the p arm of chromosome 3 (pl4>pter) and the (q12>q22).establishedno significant difference in tumor formation (Table 1). Cultures arms of chromosomes 7 (q22>qter) and 18 oneTu) from thesetumors (129 Nu 5002-1 Tu and 129 Nu 5010-5 The SOsclonal population is XYq + Yq+, and there is loss of formationhumanresembled the NMU-transformed cells. They were confirmed as copy of normal chromosomes 12, 18, and 21 due to marker pcontrast,and resembled the cells of origin by karyological analysis. In t(l2q;2l)-Ml and dell8 (ql lq23)-M6. This leads to the loss of the 18with the immortal HPV-l8 C-l cells as well as the cells treated arm of chromosome 12 (pl0>pter) and the q arm of chromosome andafter3 X 250 .tg/ml NMU were nontumorigenic for up to 6 months (q12>q22). There is a similar gain of one copy of chromosome 5 InThes.c. inoculation in athymic nude mice (Table I). 20 and a minute-M4, as was also observed in the 40s population. andgivenchromosomal abnormalities observed in various cell lines are addition, there were gains of two extra copies of chromosome 15 14.observedin Table 2 and Figs. 2 and 3. Two clonal populations were a single copy of chromosomes 4 and chemicalwasin the immortalized HPV-l 8 C-l cells at passage 17. There The cell lines treated with different concentrations of the was(25%).a major population in SOs(5 1%) and a minor population in 40s NMU showed similar changes. Only the 40s clonal population preparedsomalThese two clonal lines differed from each other in chromo- selected in NMU-treated cell lines. All of the karyotypes ofThechanges. showed further loss of one copy of chromosome 22. Duplication 40s population is XOlqTable and shows losses of normal copies of chromosome I 1 (ql4>q24) and translocation of part of the 9q to 1

NMLPA. 2 Cytogenetic characteristics of HPV-18 C-I prostate epithelial cell lines transformed by KaryotypeCell

(M)I. line Count Sex Lossor gain of normal chromosomes Markers HPV-18 C-I 550s@40s (25%) XO â€”(3,7, 13, 18) +(5, 20) 1, 2, 2A*, 4, 62. (51%) XYq+ â€”(12,18, 21) +(4*, 5,14, 15, 15, 20) 1, 1A*, 2, 4, 9B3.NMU 3X 50 @zg 40s(88%) XO â€”(7,11, 13, 18,22) +(5, 20) 1,5, 9, 9A*, 104.NMU 3 x 100 @zg 40s (73%) XO â€”(7,11. 13, 18, 19, 22) +(5, 20*) 1, 4, 5, 9, 9C, 9D*5.NMU 3 x 250 @zg 40s (94%) XO 7, 9*, 11, 13, 18, 19*, 22) +(5, 20) 1, 4*, 5, 9 9V5, IIa Tumor cell line 40s (96%) XO â€”(7,8, 10, 11, 13, 13, 18, 22) +(5, 20) 1, 4, 5, 7A(2 COP), 9Al, markersas@,present in >50%: â€”.absent: *, present in <50%; M. deletion, translocation, or derivative chromosomes; Â®, second clonal population showing different changes and described.B.

,narkers40sHPV-18 C.1 cell line countMIcount SOs t(12q;2l?)MIA= del(7)(q21) Ml = del(12)(qter>qlO;)M2= t(7@;l2) t(7pter>7p1 l:;?;;12p13>l2qter) MIA = Yq+M2A= del(3)(p14) M2 = minuteM3= t(3qter>3p14:;?) M4 (q11q23)M3A= del(5)(p13) M6 = del(l8) =5(Xpter>Xq26:;5q12>Sqter)M4 =minuteMS =del?(l8)(qllq23)M6 =t(9q:2l?)M7 =t(lpter>lq3l;:8q?)M7A =t(8q:l3q)M8 =t(4q:IOq)M8A =t(4q;lOq)M9 0;?)M9A= der.(I I )dup/t(9qter>q2 I :;I Iq24>q l4;;q24>q I 1q24>plO;;?)M9A= der.(I I )dup/t(9;I I ;?)(9q21;;l 1q24>q 14;;l I4;;q24>pter)M9BI = der.(11)dup/t(9;I I )(9qter>q2 1;;1lq24>q >qter)M9C= der(3)dup/t(3qter>p24;;I 1ql0>q24;; I 1q14>q24;;9q2 I =t(llq;?)M9D >qter)M9(v)= der(I )dup/t(I 9;11)( Iqter>q 10;;1lq I0>q24LL I IqI4>q24;;9q2 I =del(ll)(qIO)MlO =l9p+/q+Ml I = del(l0)(qter>qlO;)

578

Downloaded from cancerres.aacrjournals.org on September 23, 2021. © 1997 American Association for Cancer Research. HUMAN PROSTATEMALIGNANT TRANSFORMATION StepwiseGeneticChangesObservedinProstateCellLines In the case of two independently derived tumor cell lines from the 3 X 50 @g/mlNMU-exposed cell line compared to immortal Clonal populations I ized and NMU-transformed cell lines, there was further loss of the @EIII::@ Lass12p(plO>ptsrI p arms of chromosomes 8 (pl0>pter) and 10 (p l0>pter) and gain __._____.v 55i@r lBq(q11q23) I Gain: 4, 5, 14, 15, 1@,201 of the q arm of chromosome 8 (qlO>qter; see marker M7A, mm. Table 2). Ras and p53 Analysis. Radioimmunoprecipitation analysis of the cellular ras protein with anti-p21 antiserum revealed no differences in I Normal migration patterns or band intensities in the untreated and chemical treated cells. To determine if the alteration of cellular ras (K-ras, IImmortalizedII NMUtransformedI ITumorsi H-ras, and N-ras) and p53 genes is present in the chemical-trans ILoss:3p(p14,.ptsr)Loss'7q([email protected])lOp(plO>pt.r)ILoss: 8p (plO>ptsr) I formed HPV-l 8 C-i cells and tumor cell lines, reverse transcription I 7q(q22s.qt.r)II â€˜lSq(ql2s.q22)II 7q([email protected])I PCR and SSCP analysiswere performed.SSCP analysisof the cel 13,22Y I I lSq(ql2.q22) I @ iSq(q12sq22)I I o.in: s,@o I I 13,22&Y I lular ras genes displayed identical banding patterns in these cells as @ IGaIn:5,20 E @21>@)IGain:5,20I9(q21>qtsr) I @ mm. (ql4s.q24) I I (qlOs.qt.r) I compared to those of the control. @@ mm. ii (q14s.q24) I mm. I A similar PCR-SSCP analysis for exons 2-1 1 of the p53 gene revealed no mutation in the HPV-18 C-i parental, chemical-trans Fig. 2. StepwisegeneticchangesobservedinimmortalizedHPV-18C-l, NMU-treated HPV-l8 C-l, andtumor cell lines. formed, or tumorigenic cells, indicating that no deletion, point muta tions, or rearrangements were present.

terminus (see marker M9 and its variants) were observed. Overall, Discussion thesechangeslead to further lossof chromosome22 and the gain of parts of chromosomes 9 (q21>qter) and 11 (q14>q24). No loss of Malignant transformation of HPE cells was achieved by the cumula chromosome3p was observedin the NMU-treated cell lines. tive action of HPV-18 virus and the chemical carcinogenNMU. At least gg iiâ€• 1 2 3 4 5

\@â€˜â€¢ .J 01 1;i; Ml 1

6 7 8 9 10 11@ 12 M9A1

M7A MIA 13 14 15 16 17 18

.@ â€˜,@

@ %,@

19 20 21 22 XV

Fig. 3. Karyotypeof a tumor cell line obtainedfrom tumorexplantwith NMU (3 X 50 @ag/ml)-treatedHPV-18C-l cells.Lossof 8p and lOp wasobservedfrequently. 579

Downloaded from cancerres.aacrjournals.org on September 23, 2021. © 1997 American Association for Cancer Research. HUMAN PROSTATE MALIGNANT TRANSFORMATION two and possibly more alterations in cell gmwth properties seemto be (19, 24, and 25) and chromosome lOp (19 and 23). The gain of required. The measurable event was the development of apparently chromosome 8q is only reported by new methods of comparative unlimited growth potential as a result of HPV-l8 immortalization (5). genomic hybridization (25). The losses of chromosomes 8p and lOp Treatment of nontumorigenic early passageHPV-l8-immortalized HPE and the gain of chromosome8q specificallyobservedin the tumori cells with NMU resultedin additional changesin their growth properties. genic cell lines in the present study lead us to believe that these Concomitantly, acquired properties of the NMU-transformed cells in regions must be important in the progression to malignancy. cluded morphological alterations,the ability to grow in soft agar,and the The HPE cell system described here may be a useful in vitro tool formation of tumors in athymic mice. for dissecting the process of chemical carcinogen-induced malignant In thismodelsystem,thechemicalcarcinogenissimilarto the v-lU transformation of HPE cells of adult origin, the natural target of ras oncogene in its ability to complement HPV-18 virus in fully trans prostate carcinogenesis. Additional molecular analysis of these cells forming HPE cells. However, unlike the rapid transformationof HPV-i8 will be neededto determine the specific events that are responsible for C-l cellsobservedafterv-Ki-ras infection(5), the alterationsingrowth chemical carcinogen-induced malignant transformation. patterns after NMU treatment were delayed in their appearanceand required severalsubcultivations for visualization. Thesefindings suggest References that multiple cell divisions arerequired for fixation andexpressionof the I . Parker, S. L., Tong, T., Bolden, S., and Wingo, P. A. Cancer statistics. CA Cancer transformed phenotype in response to the chemical carcinogen. J. Clin., 46: 5â€”27.1996. It is possible that more than one genetic lesion may be required as 2. Carter, H. B., and Coffey, D. S. The prostate:an increasingmedical problem. Prostate, 16: 39â€”48,1990. well. Cooperating cellular or viral oncogenes have been shown to 3. Isaacs, J. T. Prostatic cancer: an overview. Cancer Metastasis Rev., 12: 1â€”2,1993. induce neoplastic transformation of embryonic rodent fibroblasts (7, 4. Chiarodo, A. National cancer institute roundtable on prostate cancer: future research directions. Cancer Res., 51: 2498â€”2505,1991. 8). In addition, the combined action of HPV and a chemical carcin 5. Rhim, J. S., Webber, M. M., Bellow, D., Lee, M. S., Amstein, P., Chen, L. S., and Jay. ogen has been demonstrated to produce neoplastic transformation of G. Stepwise immortalization and transformation of adult human prostate epithelial human epithelial cells (9). The interaction of HPV- I 8 and NMU in the cells by a combinationof HPV-18 and v-Ki-ras. Proc. Natl. Acad. Sci. USA, 91: 11874â€”11878,1994. induction of squamous cell carcinoma has been shown (9). Our data 6. Hukku, B., and Rhim, J. S. Role of chromosome 5 in immortalization and tumori on neoplastic transformation of HPV-l8-immortalized HPE cells by genesis of human keratinocytes. Cancer Genet. 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Card nogenesis (Lond.), 14: 329â€”332,1993. tion of the HPV-l8 C-I HPE cells by NMU suggests that other 10. Magee, P. N. The experimental basis for the role of nitroso compounds in tumor cellular oncogenes may be activated as part of the process. Our cancer. Cancer Sun'., 8: 207â€”239,1989. findings indicate that ras oncogenes were not activated in this chem II. Cooper, G. M. Cellular transforming genes. Science (Washington DC), 217: 801â€” 806, 1982. ical-induced transformation, even though ras oncogenes have been 12. Anwar, K., Nakakaki, K., Shiraishi, T., Naiki, H., Yatani, R., and Dnuzuka, M. implicated in chemical carcinogen-induced animal tumors ( I I ) and in Presence of ras oncogene mutations and human papilloma virus DNA in tumor prostatecarcinoma.Cancer Res., 52: 5991â€”5996,1992. some human prostate carcinomas (12, 13). This system may be useful 13. Konishi, N., Enomoto, T., Buzzard, G., Ohshima, M., Ward, J. M., and Rice, J. M. in efforts to detect and characterize other cellular genes contributing K-ras activation and ras p21 expressionin latent prostaticcarcinomasin Japanese to the neoplastic phenotype of HPE cells. men. Cancer (Phila.), 69: 2293â€”2299,1992. 14. Levine, A. J., Momand, J., and Finlay. C. A. The p53 tumor suppressor gene. Nature Alterations of the tumor suppressorgene p53 have been associated (Lond.), 351: 453â€”456,1991. with malignant transformation in human and animal systems (14, 15) 15. Weinberg, R. A. Tumor suppressor genes. Science (Washington DC), 254: 1138â€” and have also been implicated in the pathogenesis of prostate cancer 1146,1991. 16. Carter, B. S., Ewing, C. M., Ward, W. S., Treiger, B. F., Aalders, T. W., Schalken, (16, 17). Loss of genetic material from the distal portion of chromo J. A., Epstein, J. L., and Isaacs, W. B. Allelic loss of chromosomes 16q and 101 in some 17p in 3 of 18 human prostate cancers has been shown ( I 6). humanprostatecancer.Proc. NatI. Acad. Sd. USA, 87: 8751â€”8755,1990. 17. lasses,W. B., Caner, B. S.,and Ewing, C. M. Wild-type p53 suppressesgrowthof human Expression of wild-type p53 in prostate cancer cell lines with mutant prostatecancercellscontainingmutantp53 alleles.CancerRes.,51: 4716â€”4720,1991. alleles will suppresstheir growth (17). However, an uncertain role for 18. Brooks, J. D., Bova, G. S., Ewing, C. M., Piantadosi, S., Carter, B. S., Robinson, J. C., p53 genealterationin55 clinicalhumanprostatecancershasrecently Epstein, J. I., and lsaacs, W. B. An uncertain role for p53 gene alterations in human prostatecancer.Cancer Res., 56: 3814â€”3822,1996. been reported (18). Our analysis of exons 2â€”11of the p53 gene in 19. Mitelman, F. Catalog of ChromosomeAberrations in Cancer, 4th ed. New York: parental HPV-l8 C-l , NMU-treated, and tumorigenic cell lines mdi Wiley-Liss, Inc., 1991. cates an absence of point mutations, deletions, or rearrangements in 20. Brothman, A. R., Peehi,D. M., Patel,A. M., and MeNeal, J. E. Frequencyand pattem of karyotypicabnormalitiesinhumanprostatecancer.CancerRes.,50:3795â€”3803,1990. this tumor suppressorgene. This finding suggestsa different pathway 21. Atkin, N. B., and Baker, M. C. Chromosome 7dq deletions: observations on 13 involved in the carcinogenic progression of these cells. malignanttumors.Cancer Genet. Cytogenet.,67: 123â€”125,1993. 22. Arps, S., Rodewald, A., Schmalenberger, B., Carl, P., Bressel, M., and Kastendieck, Stepwise chromosome changes observed in the present model sys H. Cytogenetic survey of 32 cancers of the prostate. Cancer Genet. Cytogenet., 66: tem were compared to what is reported in the literature for prostate 93â€”99,1993. cancer studied either by classical cytogenetic (19â€”22)or molecular 23. Trybus, T. M., Tanya, M., Burgess, A. C., Wojno, K. J., Glover, T. W., and Macoska, J. A. Distinct areasof allelic losson chromosomalregions lOp and loq in human methods (23â€”25).Lossesof chromosomes Y, 1, 2, 5, 3p, 7q, 8p, lop, prostatecancer.Cancer Res., 56: 2263â€”2267,1996. I 1 or 1lq, l3q, l7/l7p, and l8q and gains of chromosomes 7, 14, 20, 24. Vocke, C. D., Possatti, R. 0., Bostwick, D. G., Florence, C. D., Jennings, S. B., Strop, 22, 8q, and 9q in prostate cancer have been reported. In the present S. E., Duray. P. H.. Liotta. L. A., Emmert-Buck, M. R., and Linehan, M. W. Analysis of 99 microdissectedprostatecarcinomasrevealsa high frequencyof allelic losson study, losses of chromosomes Y, 3p, 7q, 8p, 9p, lOp, and l8q and chromosome8pl2â€”2l.CancerRes., 56: 2411â€”2416,1996. gains of chromosomes 5, 9q, 1lq, and 20 are also observed. The most 25. Cher, M. J., Bova, G. S., Moore, D. H., Small, E. J., Caroll, P. R., Pin, S. S., Epstein, J. I., Isaacs, W. B., and Jensen, R. H. Genetic alterations in untreated metastases and frequent changes observed by either classical cytogenetic or molecu androgen-independentprostatecancerdetectedby comparativegenomic hybridiza lar genetic methods, however, are allelic losses of chromosome 8p tion andallelotyping.CancerRes.,56: 3001â€”3092,1996.

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Johng S. Rhim, Sunji Jin, Mira Jung, et al.

Cancer Res 1997;57:576-580.

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