Murine Double-Minute 2 Homolog Single Nucleotide Polymorphisms 285 and 309 in Cervical Carcinogenesis

Mol Diagn Ther (2015) 19:235–244 DOI 10.1007/s40291-015-0153-4 ORIGINAL RESEARCH ARTICLE Murine Double-Minute 2 Homolog Single Nucleotide Polymorphisms 285 and 309 in Cervical Carcinogenesis Andrzej Roszak1,2 • Matthew Misztal3 • Anna Sowińska4 • Pawel P. Jagodziński3 Published online: 30 July 2015 Ó The Author(s) 2015. This article is published with open access at Springerlink.com Abstract Background and Objective In Caucasians, the MDM2 single nucleotide polymorphism (SNP) 285 G[C (rs117039649) neutralizes the effect of 309 T[G (rs2279744), which increases MDM2 expression and impairs the p53 pathway. In this study, we examined the distribution of these two SNPs in Polish women with squamous cell carcinoma (SCC) (n = 379), adenocarcinoma (n = 59) and other cervical tumor types (n = 18). Methods The polymerase chain reaction-restriction fragment length polymorphism technique and DNA sequencing were employed in our study. Results The P trend value calculated for the MDM2 285 G[C polymorphism was statistically significant (Ptrend = 0.016) for SCC. Using logistical regression analysis adjusted for the effect of age, pregnancy, oral contraceptive use, tobacco smoking, and menopausal status, we observed that the MDM2 285 G[C SNP protected against SCC, with an adjusted odd ratio (OR) for the C carriers Electronic supplementary material The online version of this article (doi:10.1007/s40291-015-0153-4) contains supplementary material, which is available to authorized users. & Pawel P. Jagodziński 1 Department of Radiotherapy and Gynecological Oncology, Greater Poland Cancer Center, Poznan, Poland 2 Department of Electroradiology, Poznan University of Medical Sciences, Poznan, Poland 3 Department of Biochemistry and Molecular Biology, Poznan University of Medical Sciences, 6 Świe˛cickiego St., 60-781 Poznan, Poland 4 Department of Computer Science and Statistics, Poznan University of Medical Sciences, Poznan, Poland versus G/G genotype of 0.536 (P = 0.019). Stratified analyses of MDM2 285 G[C revealed a protective role of the C allele against SCC in women with a positive history of oral contraceptive use (age-adjusted OR 0.413, P = 0.021) and in premenopausal women (age-adjusted OR 0.362, P = 0.022). We also found that the 285GG/309GG vs 285GG/309 TT genotype increased the risk of SCC (adjusted OR 1.890, P = 0.005). However, the 285CC/ 309GG ? 285GC/309GG versus 285GG/309GG genotype reduced the risk of SCC (adjusted OR 0.311, P = 0.004). Conclusion Our results demonstrate that the MDM2 285C gene variant and 285CC/309GG ? 285GC/309GG genotypes protect against SCC, most likely by neutralizing the effect of the 309 T[G SNP. The 285GG/309GG genotype increases the risk of SCC possibly due to increased MDM2 expression. Key Points The MDM2 309 T[G (rs2279744) single nucleotide polymorphism (SNP), causes increased MDM2 expression whose action is neutralized by 285 G[C (rs117039649) SNP, located on 24 bps from SNP309 SNP. Our genetic assessment demonstrated that the MDM2 285 G[C polymorphism protects against squamous cell carcinoma (SCC), but the 309 T[G does not have the same quality. The combined 285CC/309GG ? 285GC/309GG genotypes protect against SCC, whereas the 285GG/ 309GG genotype increases the risk of SCC in the Caucasian populations. 236 A. Roszak et al. 1 Introduction 2 Patients and Methods Cervical tumors are the third most frequent type of neoplasia that causes death among women worldwide [1]. The incidence of cervical neoplasia is especially high in developing countries, accounting for 86 % of all newly diagnosed cases worldwide [1]. Infections with high-risk types of human papillomavirus (HR-HPV) are thought to be the main etiological agents of cervical lesions [2]. HPV infections have been identified in nearly 100 % of all squamous cell carcinoma (SCC) cases [3], and it has been estimated that approximately 15–40 % of sexually active women are infected with HR-HPV [4]. Despite the frequency of HPV infections, only a small percentage of these women exhibit persistent positivity for HR-HPV types [5]. Apart from HPV, other susceptibility variables of cervical lesions have been identified, including social status, tobacco consumption, multi-parity, oral contraceptive use, age of sexual debut, and environmental pollutants [6, 7]. These data indicate that interactions between various susceptibility variables and genetic backgrounds are essential for the cancerous transformation of HR-HPV-infected cervical epithelial cells to cervical malignancies [6–9]. Expression of the HPV E6/E7 oncoproteins leads to the inactivation of tumor suppressor proteins p53 and retinoblastoma tumor suppressor protein (pRB), eventually causing uncontrolled cell cycle progression, increased cell survival, and accumulation of DNA damage [10, 11]. Murine double-minute 2 homolog (MDM2) is a major negative regulator of p53 protein levels [12, 13]. Furthermore, MDM2 interacts with pRB and binds to the activation domain of the E2F1 transcription factor that inhibits pRB regulatory functions [10]. Abnormal MDM2 levels have been linked to an increase in genetic errors that account for the onset and development of various diseases, including cancer [14, 15]. The T[G transition (rs2279744) at position 309 in the first intron of MDM2 in the promoter region causes up-regulation of both MDM2 mRNA and protein, leading to impairment of the p53 pathway [16]. In Caucasians, a second functional single nucleotide polymorphism (SNP), 285 G[C (rs117039649), has been identified in the promoter region located 24 bps from SNP309 [17, 18]. This second SNP neutralizes the effect of the 309 T[G transition in MDM2, resulting in decreased MDM2 transcription [18]. There have been controversial findings demonstrating that the 309 MDM2 SNP is a susceptibility factor for the development of cervical cancer in disparate ethnicities [19–23]. The purpose of this study was to investigate the distribution of MDM2 309 T[G and 285 G[C SNPs in women with squamous cell carcinoma (SCC) (n = 379), adenocarcinoma (n = 59) and other cervical tumor types (n = 18) and controls (n = 481) from a Polish population. 2.1 Study Population The study population consisted of 456 patients with an assessed stage, histological grade and cervical tumor type based on the International Federation of Gynecology and Obstetrics. Patients’ data were obtained from patients enrolled between July 2008 and August 2014 at the Department of Radiotherapy of the Greater Poland Cancer Center in Poznań, Poland. The patient group included randomly selected women with SCC (n = 379), adenocarcinoma (n = 59) or other histologic types of tumor (n = 18) (Table 1). The control group consisted of 481 unrelated healthy female volunteers selected during medical examination at the University Hospital, Clinic of Gynecological Surgery at Poznań University of Medical Science (Table 1). Information regarding pregnancy, oral contraceptive use, tobacco smoking, and (...truncated)