MDM2 SNP309 Polymorphism as Risk Factor for Susceptibility and Poor Prognosis in Renal Cell Carcinoma HiroshiHirata, 1 Yuji Hinoda, 2 NobuyukiKikuno, 1 Ken Kawamoto, 1 YutakaSuehiro, 2 YuichiroTanaka, 1 and Rajvir Dahiya 1 Abstract Purpose: MDM2 is a major negative regulator of p53, and a single nucleotide polymorphism in the MDM2 promoterregionSNP309(rs2279744)hasbeenshowntoincreasetheaffinityofthe transcriptional activator Sp1, resulting in elevated MDM2 transcription and expression in some cancers.There is currently no information about the role of MDM2 polymorphism in renal cell carcinoma (RCC).We investigated polymorphisms in p53-related genes, including MDM2 , and their interactions in renal cancer. Experimental Design: We genotyped three single nucleotide polymorphisms of three genes (p53 Arg 72 Pro, p21 Ser 31 Arg, and MDM2 SNP309) in 200 patients with renal cancer and 200 age- and gender-matched healthy subjects. Genotyping was confirmed by direct DNA sequencing. Samples that showed significant polymorphic variants were analyzed for MDM2 expression by immunohistochemistry. Association of polymorphic variants on survival of RCC patientswasanalyzedbyKaplan-Meiercurves. Results: AsignificantincreaseintheGGgenotypeofthe MDM2 SNP309 wasobservedinRCC patientscomparedwithhealthycontrols(oddsratio,1.80;95%confidenceinterval,1.14-2.84).To investigatetheeffectof the MDM2 SNP309polymorphismonMDM2expression,immunohisto- chemistry was done in genotyped RCC tissues. Positive staining for MDM2 was detected in 2 of15(13%)TTgenotype,4of15(26%)TGgenotype,and5of10(50%)GGgenotypecarriers. The frequencyof MDM2 expressionin GG genotype carriers was significantlyhigher thanthatin TTgenotype carriers.Polymorphismsof p53 Arg 72 Pro and p21 Ser 31 Arg didnot show significant associationwith RCC. Inunivariate and multivariate analysis, MDM2 SNP309GGgenotypewas independentlyassociatedwithpoorprognosis.Kaplan-Meiercurveanalysisshowedthatsurvival ofpatientswithGGcarrierswassignificantlyworsethanthatofcarrierswithTG+TTgenotypes. Conclusions: This is the first report to show a significant association between functional poly- morphismsin MDM2 andincreasedriskofdevelopingrenalcancer.Inaddition,the MDM2 poly- morphism was shown to be an independent adverse prognostic factor for RCC. Patients with MDM2 309GGgenotype showedworseprognosis andlowsurvival. Renal cell carcinoma (RCC) is the third leading cause of death among urological tumors, accounting for f2% of adult malignancies (1). Although the rate of detection of incidental RCC has increased with improved diagnostic techniques, metastatic lesions are still found at diagnosis in f25% of RCC patients. Etiologic studies of familial and sporadic RCC have shown that the von Hippel-Lindau tumor suppressor gene, located on chromosome 3p25-26, is associated with RCC. Mutation of the von Hippel-Lindau gene causes familial von Hippel-Lindau disease, and the loss of two von Hippel-Lindau alleles has been observed in the vast majority of sporadic RCC (2, 3). Epidemiologic studies have suggested that gender, obesity, smoking, analgesic, diuretic abuse, and environmental factors are associated with RCC (4, 5). p53 is a tumor suppressor gene that initiates apoptosis in response to severe DNA damage (6). p21 (CDKN1A, Waf1) is a cell cycle checkpoint gene functioning as downstream effectors of p53 and acts as an inhibitor of cyclin-dependent kinase (7). In response to DNA damage, cell cycle arrest at the G 1 to S phase is caused by p21 through p53 up-regulation (6). MDM2 is a crucial negative regulator of p53 through several mecha- nisms. MDM2 directly binds to p53, resulting in the inhibition of p53 transactivation activity (8–10). MDM2 also acts as an ubiquitin protein ligase and controls p53 by targeting it for proteasomal degradation (8–10). Therefore, overexpression of Imaging, Diagnosis, Prognosis Authors’Affiliations: 1 Department of Urology, San FranciscoVeterans Affairs Medical Center and University of California at San Francisco, San Francisco, California and 2 Department of Laboratory Medicine,Yamaguchi University School of Medicine,Yamaguchi, Japan Received3/14/07;revised5/2/07;accepted5/7/07. Grant support: NIH grants RO1CA101844, RO1AG21418, R01CA111470, R01CA108612, andT32-DK07790;Veterans Affairs Research Enhancement Award Program award; Merit Review grants; andYamada Science Foundation. Thecostsofpublicationofthisarticleweredefrayedinpartbythepaymentofpage charges.This article must therefore be hereby marked advertisement in accordance with18U.S.C.Section1734solely toindicatethisfact. Requests for reprints: Rajvir Dahiya, Urology Research Center (112F),Veterans Affairs Medical Center and University of California at San Francisco, 4150 Clement Street, San Francisco, CA 94121. Phone: 415-750-6964; Fax: 415-750-6639; E-mail: rdahiya@urol.ucsf.edu. F 2007AmericanAssociationforCancerResearch. doi:10.1158/1078-0432.CCR-07-0609 www.aacrjournals.org Clin Cancer Res 2007;13(14) July15, 2007 4123 Research. on June 17, 2020. © 2007 American Association for Cancer clincancerres.aacrjournals.org Downloaded from