Imaging, Diagnosis, Prognosis MDM2 Promoter SNP309 Is Associated with Risk of Occurrence and Advanced Lymph Node Metastasis of Nasopharyngeal Carcinoma in Chinese Population Gangqiao Zhou,1, 2 , 3 Yun Z hai,1, 2 Ying Cui,4 Xiumei Zhang,2 Xiaojia Dong,3 HaoYang,1, 2 Ying He,5 KaitaiYao,5 Hongxing Zhang,1, 2 Lianteng Zhi,1, 2 XiaoyanYuan,1, 2 Wei Qiu,1, 2 Xiaoai Zhang,1, 2 Ya n Sh e n, 3 Boqing Qiang,3 and Fuchu He1, 2 , 3, 6 Abstract Purpose: Mouse double minute 2 (MDM2) is a key negative regulator of the p53 activity. Recently, a polymorphism in the MDM2 intronic promoter, SNP309, was shown to influence MDM2 expression and p53 activity.We examined whether the SNP309 was related to the risk of developing nasopharyngeal carcinoma (NPC) among Chinese populations. Experimental Design: We genotyped the SNP309 in two independent case-control popula- tions in southern China, one is from Guangxi province (including 593 NPC patients and 480 controls) and the other is from Guangdong province (including 239 patients and 286 controls), by PCR direct sequencing. Multivariate logistic regression analysis was used to calculate adjusted odds ratio (OR) and 95% confidence interval (95% CI). Results: We observed that compared with theTT genotype, the genotypes containing G allele (GT + GG genotype) were associated with significant increased susceptibility to NPC in both Guangxi (OR, 1.43; 95% CI, 1.04-1.91) and Guangdong population (OR, 1.53; 95% CI, 1.00-2.36).When these two sample sets were combined, the OR of the GT + GG genotype developing NPC was 1.45 (95% CI, 1.12-1.85) compared with the TT genotype. Furthermore, compared with theTT genotype, the GT + GG genotype was also significantly associated with the advanced lymph node metastasis (OR, 1.84; 95% CI, 1.09-3.05). Conclusions: Our findings suggest that the MDM2 SNP309 may be a risk factor for the occurrence and advanced neck lymph node metastasis of NPC in Chinese population. Nasopharyngeal carcinoma (NPC) is an epithelial malignancy (1). The marked racial and geographic differences in NPC with striking racial and geographic distribution differences (1). susceptibility have been considered as a multifactorial and High incidence rates are observed in the southern Chinese and polygenic event with EBV, environmental, and genetic compo- other individuals of Chinese descent, including Singaporeans, nents (1, 5–9). The identification of susceptibility genes Taiwanese, and Hong Kong Chinese (2–4). These incidence contributing to NPC would assist in predicting individual and rates are f100-fold higher than in the Caucasian populations population risks of NPC development and would help to clarify pathogenesis of this malignancy. Linkage analyses have suggested several chromosomal regions that may harbor NPC susceptibility genes. Lu et al. (10) were the first to map a susceptibility locus to chromosome 1 Authors’ Affiliations: Department of Genomics and Proteomics, Beijing Institute 6p22 in affected sib pairs collected from southern China, of Radiation Medicine; 2Department of Functional Genomics, Beijing Proteome Research Center; 3Chinese National Human Genome Center at Beijing, Beijing, supporting the involvement of the human leukocyte antigens in China; 4Cancer Institute of Guangxi, Nanning, China; 5Institute of Cancer the pathogenesis of NPC. Recently, two genome-wide searches Research, Nanfang Medical University, Guangzhou, China; and 6Institute of carried out in 20 Cantonese-speaking families from the Biomedical Sciences, Fudan University, Shanghai, China Guangdong province and 18 families from the Hunan province Received 9/13/06; revised 1/1/07; accepted 2/16/07. Grant support: Chinese High-tech Program 2001AA224011and 2002BA711A10, in southern China provided support for susceptibility loci on Medicine and Health Research Program 01Z018, Chinese National Science Fund for chromosome 4p15.1-q12 and 3p21.31-21.2, respectively Creative Research Groups 30321003 and 30621063 Chinese ‘‘973’’ Project Program (11, 12). Association studies have also been done, and some 2006 CB910803, and Beijing Science andTechnology NOVAprogram 2006A54. of the identified loci, including the cyclin D1 (CCND1; ref. 13), The costs of publication of this article were defrayed in part by the payment of page DNA repair genes hOGG1 and XRCC1 (14), heat shock protein charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section1734 solely to indicate this fact. 70-2 (HSP70-2; ref. 15), and glutathione S-transferase M1 Note: G. Zhou andY. Zhai contributed equally to this work. (GSTM1; refs. 16, 17), seem to contribute to disease suscepti- Requests for reprints: Fuchu He or Gangqiao Zhou, Department of Genomics bility. Recently, we also reported an association between risk of and Proteomics, Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing NPC and the polymorphisms in the promoter of palate, lung 100850, China. Phone/Fax: 86-10-68177417 or 86-10-80705255; E-mail: [email protected] or [email protected]. and nasal epithelial clone (PLUNC) gene, which codes a protein F 2007 American Association for Cancer Research. that may function in the innate immune response in regions of doi:10.1158/1078-0432.CCR-06-2281 mouth and nose (18). Despite these advances, the alleles that www.aacrjournals.orgClin Cancer Res 2007;13(9) May 1,2627 2007 Downloaded from clincancerres.aacrjournals.org on September 28, 2021. © 2007 American Association for Cancer Research. Imaging, Diagnosis, Prognosis account for most of the genetic susceptibility to NPC remain Materials and Methods undiscovered. It is well known that the p53 pathway plays a key role in Study subjects. This study consisted of two populations of patients preventing carcinogenesis by causing cell cycle arrest or with NPC and controls resided in Guangxi and Guangdong province, apoptosis (19–21). The activity of p53 may be inactivated respectively, both of which located in southern China. The Guangxi through mutations in the p53 gene. It has also been shown population consisted of 593 patients with NPC and 480 controls. All that in cancers lacking p53 mutations, the p53 function is subjects were unrelated ethnic Han Chinese and residents in Nanning abolished or attenuated by other mechanisms, such as the city and the surrounding regions. All patients with NPC were newly overexpressed human homologue of the mouse double minute diagnosed and pathologically confirmed, which were consecutively 2 (MDM2) protein (22). The MDM2 acts as a principal recruited at the Guangxi Cancer Hospital (Nanning, China) between negative regulator of p53 through at least three different ways. September 2003 and July 2005. The response rate for case patients was First, by binding to transactivation domain of p53, it inhibits 95%. Patients that received chemotherapy or radiotherapy before its transcriptional activity (23). Second, MDM2, which acts as surgery or had other type of cancer were excluded from this study. Tumor staging was done according to the tumor-node-metastasis an ubiquitin ligase, promotes p53 degradation (24). Third, on classification by the 1997 American Joint Committee on Cancer system binding to p53, MDM2 favors the export of p53 because it (37). All tumor-node-metastasis classifications were determined by contains a nuclear export signal (25). Additionally, MDM2 also senior pathologists of the hospital based on the postoperative seems to possess significant p53-independent functions, histopathologic examination. The controls were randomly selected through interacting with other cellular proteins that are from a community cancer screening program for early detection of important in cell cycle control, including pRb, E2F/DP1, and cancer conducted in the same regions during the same time period as p19ARF, although some of these functions are less well the NPC cases were collected. The selection criteria for the controls characterized (26, 27). It has been shown that transgenic mice included no individual history of cancer. The response rate for control with overexpression of MDM2 are predisposed to spontaneous subjects was 91%. At recruitment, informed consent was obtained from tumor formation and show both the p53-dependent and the each subject, and personal information on demographic factors, p53-independent tumorigenicity of MDM2 (28). In humans, medical history, and tobacco and alcohol use were collected via the amplification and/or overexpression of the MDM2 have structured questionnaire. The Guangdong population, which contained 239 NPC patients and 286 controls, has been described in detail been extensively described in more than 40 different types of previously (18). As described previously, the data on tumor staging, malignancies (29), and this overexpression has been exten- smoking, and drinking were not available for this sample set. This study sively linked with a worse clinical prognosis, an increased was done with the approval of the Ethical Committee of Chinese metastasis, as well as a decreased response to therapeutic National Human Genome Center. intervention in cancers (29). With regard to NPC, MDM2 is Polymorphism genotyping. We extracted genomic DNA from periph- overexpressed in both EBV-infected cells and 31% to 56% of eral blood leukocytes of 5 mL whole blood using standard phenol/ the tumors (30–33). Furthermore, it has been shown that the chloroform protocols. DNA samples were diluted to 10 ng/AL and MDM2 mRNA overexpression was significantly related to neck distributed to 96-well plates; each 96-well