Association ofMDM2andp53Polymorphisms with the Advancement of Cervical Carcinoma

Genetic Variations in MDM2 Gene Contribute to Renal Cell Carcinoma Susceptibility: A Genotype-Phenotype Correlation Study

BACKGROUND

This study aimed to investigate the polymorphic genotypes of MDM2 rs937282, rs937283, rs2279744, and rs769412, as well as the combined effects of MDM2 genotypes and environmental factors on RCC susceptibility.

METHODS

A total of 135 RCC patients and 590 controls were recruited for MDM2 genotyping using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Quantitative PCR was performed to assess MDM2 mRNA levels among 30 healthy individuals and 22 RCC patients.

RESULTS

MDM2 rs2279744, but not other polymorphisms, was significantly associated with an increased RCC risk (p = 0.0133). The MDM2 rs2279744 G allele was identified as a risk factor for RCC (odds ratio [OR] = 1.49, 95% confidence interval [CI] = 1.14-1.96, p = 0.0047). Among smokers (p = 0.0070), alcohol drinkers (p = 0.0233), individuals with hypertension (p = 0.0041), diabetes (p = 0.0225), and those with a family history of cancer (p = 0.0020), the MDM2 rs2279744 GT and GG genotypes exhibited increased RCC risks. However, this risk effect was not observed in non-smokers, non-drinkers, or individuals without hypertension, diabetes, or a family cancer history (all p > 0.05). Moreover, MDM2 mRNA levels were significantly higher in RCC patients compared to controls and varied among the rs2279744 genotypes, with GG genotype exhibiting the highest expression levels among both RCC patients and controls.

CONCLUSIONS

This study highlights the association between MDM2 rs2279744 genotypes and RCC risk, suggesting that genotype-associated MDM2 mRNA levels could contribute to early RCC detection. Further studies are warranted to elucidate the detailed mechanisms underlying the role of MDM2 in RCC development.

Associations of MDM2 rs2279744 and TP53 rs1042522 polymorphisms with cervical cancer risk: A meta-analysis and systematic review

Background

Although the association between MDM2 rs2279744 and TP53 rs1042522 polymorphisms and cervical cancer has been reported, the results of its correlation were contradictory. Thus, we conducted a meta-analysis to precisely verify the relationships between MDM2 rs2279744 and TP53 rs1042522 polymorphisms and cervical cancer.

Methods

We thoroughly searched the PubMed, Web of Science, Embase, and Scopus databases for all potential articles from inception to June 2022 and used R Version 4.1.2 and STATA software 12.0 for the meta-analysis. The odds ratios (ORs), 95% confidence intervals (CIs) and 95% prediction intervals (PIs) were calculated to evaluate the associations. Subgroup analyses stratified by ethnicity, source of control, quality score and adjustment were further conducted to assess the relationship between MDM2 rs2279744 and TP53 rs1042522 polymorphisms and cervical cancer.

Results

A total of 30 case-control studies involving 5025 cases and 6680 controls were included. All the included studies were population-based or hospital-based studies. The overall analysis showed that MDM2 rs2279744 polymorphism was closely related to an increased risk of cervical cancer in the recessive model (GG vs GT + TT: OR = 1.602, 95% CI: 1.077-2.383, P = 0.020) and homozygote model (GG vs TT: OR = 1.469, 95% CI: 1.031-2.095, P = 0.033, 95% PI: 0.516-4.184). A significant correlation between TP53 rs1042522 polymorphism and cervical cancer was observed in two models (CC + CG vs GG: OR = 1.759, 95% CI: 1.192-2.596, P = 0.004, 95% PI: 0.474-6.533; GG vs CC: OR = 2.442, 95% CI: 1.433-4.162, P = 0.001, 95% PI: 0.456-13.071).

Conclusions

This meta-analysis revealed that MDM2 SNP309T>G and TP53 rs1042522 C>G polymorphisms were associated with the increased risk of cervical cancer.

Long non-coding RNA TUG1 sponges microRNA-381-3p to facilitate cell viability and attenuate apoptosis in cervical cancer by elevating MDM2 expression

OBJECTIVE

Based on the theory that long non-coding RNAs (lncRNAs) sponge microRNAs (miRNAs) to engage in cervical cancer development, this work was set out to investigate the possible role of lncRNA taurine upregulated gene 1 (TUG1) and miR-381-3p in the development of cervical cancer.

METHODS

TUG1, miR-381-3p and murine double minute 2 (MDM2) expression were measured in cervical cancer tissues and cells. The nexus between TUG1 and clinicopathological features of cervical cancer was discussed. The biological functions of TUG1, miR-381-3p and MDM2 on cervical cancer cell process were interpreted via gain- and loss-of-function experiments. Also, tumor xenograft in nude mice was conducted in vivo. The interactions between TUG1, miR-381-3p and MDM2 were identified.

RESULTS

TUG1 and MDM2 raised while miR-381-3p reduced in cervical cancer. TUG1 expression was related to tumor size, differentiation, international federation of gynecology and obstetrics stage and lymph node metastasis of cervical cancer. Restored miR-381-3p, depleted TUG1 or reduced MDM2 decreased viability, colony-forming, migration and invasion abilities, and facilitated apoptosis of cervical cancer cells. Xenografted tumors grew slowly upon injection with restored miR-381-3p and depleted TUG1. TUG1 bound to miR-381-3p and miR-381-3p targeted MDM2.

CONCLUSION

On all accounts, this present study provides evidence that silencing TUG1 depressed cervical cancer cell progression through miR-381-3p/MDM2 axis, highlighting a theoretical basis for cervical cancer treatment.

A DHX9-lncRNA-MDM2 interaction regulates cell invasion and angiogenesis of cervical cancer

Cervical cancer (CC) is the third most common carcinoma and the fourth leading cause of cancer-associated mortality in women. Here, we report that MDM2-DHX9 interaction mediates CC motility and angiogenesis in a long noncoding RNA-dependent fashion. A long noncoding RNA, named lnc-CCDST, is significantly downregulated in CC tissues, and binds to pro-oncogenic DHX9. DHX9 is upregulated in CC tissue, and promotes CC cell motility and angiogenesis. The lnc-CCDST and DHX9 interaction promotes DHX9 degradation through the ubiquitin proteasome pathway. Furthermore, DHX9 bound to E3 ubiquitin ligase MDM2, and this interaction is enhanced by lnc-CCDST. Thus, lnc-CCDST promotes DHX9 degradation by serving as a scaffold to facilitate the formation of MDM2 and DHX9 complexes. Moreover, HPV oncogenes E6 and E7 abolish the expression of lnc-CCDST resulting in the increase of DHX9. Our results have revealed a novel mechanism by which high-risk HPVs promote motility and angiogenesis of CC by inhibiting expression of lnc-CCDST to disrupt MDM2 and DHX9 interaction, and DHX9 degradation, and identified a potential therapeutic target for CC.

Association of PIK3CA and MDM2 SNP309 with Cervical Squamous Cell Carcinoma in a Philippine Population

Background: PIK3CA and MDM2 SNP309 have been studied to be associated with cervical cancer. PIK3CA mutation is associated with poor treatment response and low survival rate while MDM2 is associated with tumorigenesis and poor prognosis in cervical cancer. Thus, we determined the prevalence of PIK3CA and MDM2 mutations in Filipino cervical cancer patients. Methods: Twenty-eight formalin-fixed paraffin-embedded cervical squamous cell carcinoma and 16 non-malignant cervix tissue biopsies of Filipino patients were subjected to PIK3CA gene and MDM2 SNP309 (rs2279744) analysis. Results: PIK3CA gene was found mutated in three (10.71 %) out of 28 cervical cancer patients included in this study. Among the HPV-negative cervical cancer patients, two (28.57 %) were positive for PIK3CA mutation and only one (4.76 %) tested positive among the HPV-positive cervical cancer patients. MDM2 SNP309 analysis revealed that T allele (71.43%) was more common in cervical cancer patients compared to the control group. TG genotype (p = 0.03; OR = 0.18, 95% CI 0.04-0.76) was associated with lower rates of cervical cancer when TT genotype was used as a reference point. Conclusion: PIK3CA gene mutation was present among Filipino cervical cancer patients and not in control patients. MDM2 SNP309 analysis revealed that TG genotype has lower association to cervical cancer when compared with the TT and GG genotypes.

Meta-Analysis of Polymorphic Variants Conferring Genetic Risk to Cervical Cancer in Indian Women Supports CYP1A1 as an Important Associated Locus

Objective: Association of multiple polymorphic variants with cervical cancer has been elucidated by several candidate gene based as well as genome-wide association studies. However, contradictory outcomes of those studies have failed to estimate the true effect of the polymorphic variants on cervical cancer. Methods: Literature mining of the PubMed database was done to gather all the publications related to genetic association with cervical cancer in India. Out of 98 PubMed hits only 29 genetic association studies were selected for meta-analysis based on specific inclusion criteria. A fixed-effect meta-analysis was performed to evaluate the overall association of the genetic polymorphisms with cervical cancer. Cochran’s Q test was performed to assess between study heterogeneity. Publication bias was also estimated by funnel plots and Egger’s regression test. Further, sub-group analysis was conducted by fixed-effect meta-regression to assess the impact of polymorphisms on cervical cancer in the presence of Human Papilloma Virus (HPV). Result: Following a fixed-effect model, meta-analysis was conducted that revealed 2 polymorphic variants viz. ‘deletion polymorphism (Del2) (OR=1.79, 95% CI= 1.08-2.95, P=0.023) in GSTM1’ and ‘rs1048943 (OR = 2.34, 95% CI=1.37-3.99, P=0.0018) in CYP1A1’ to be associated with cervical cancer. However, multiple testing correction showed only rs1048943 of CYP1A1 to be significantly associated (P-value=0.029) with cervical cancer with significant publication bias (P-value=0.0113) as estimated by Egger’s regression test. The polymorphic variants ‘rs1801131’, ‘rs1801133’, ‘rs2430561’, ‘rs1799782’, ‘rs25486’ and ‘rs25487’ showed significant (p<0.05) evidence of heterogeneity between studies by Cochran’s Q test and also by heterogeneity index (I2) calculation. Conclusion: Therefore, our study revealed significant association of rs1048943 in CYP1A1, but a nominal association of deletion polymorphism (Del2) in GSTM1 with cervical cancer, which provides a comprehensive insight on the true effect of the polymorphisms, reported in various case-control studies, on the risk of the development of cervical cancer in Indian women.

Association of rs2279744 and rs117039649 promoter polymorphism with the risk of gynecological cancer: A meta-analysis of case-control studies

BACKGROUND

Increasing evidence has suggested that rs2279744 is associated with rs117039649 polymorphism, which can increase the risk of gynecological cancers, including cervical, ovarian, breast, and endometrial cancer. The results are inconsistent so that we performed a meta-analysis of current literature to clarify the impacts of these polymorphisms on gynecological cancer.

METHODS

Eligible articles were identified through an exhaustive search of relevant databases including PubMed, Embase, Web of science, Springer Link, Chinese National Knowledge Infrastructure (CNKI), and Weipu database for the period up to July 2016. Data about the association between single nucleotide polymorphisms (SNPs) and cancer risk were refined from the selected articles as well as other information about cases and controls, and all of them were extracted by 2 independent researchers and pooled odds ratio with 95% confidence interval was calculated.

RESULTS

This analysis included 24 articles, 27 case-control studies of rs2279744 polymorphism and 3 case-control studies of rs117039649 polymorphism. Significant association with the risk of gynecological cancer was observed for both SNPs. Subgroup analysis by ethnicity and cancer type (cervical, ovarian, breast, and endometrial) also showed a positive relationship between rs2279744 polymorphism and gynecological cancer risk in Caucasian; and there was also a notable association between rs2279744 polymorphism and cervical cancer.

CONCLUSIONS

We found that rs2279744 (SNP309) and rs117039649 (SNP285) were both associated with the risk of gynecological cancers. Subgroup analysis showed that rs2279744 (SNP309) was associated with the risk of gynecological cancers in Caucasian and Asian according to the ethnicity and cancer type, especially for endometrial cancer.

Upregulation of the BDNF/TrKB pathway promotes epithelial-mesenchymal transition, as well as the migration and invasion of cervical cancer

Brain-derived neurotrophic factor (BDNF) has previously been demonstrated to be associated with several types of cancer. In addition, its receptor, tropomyosin related kinase B (TrkB) is involved in tumor invasion and metastasis. Epithelial-mesenchymal transition (EMT) is associated with metastasis in cancers. Thus, The aim of the present study was to examine whether BDNF/TrKB expression is linked to a poor survival and the acquisition of the EMT phenotype in cervical cancer. We found that a high positive expression of BDNF/TrKB was associated with poor survival in cervical cancer. Our results revealed that high expression levels of BDNF/TrKB were observed in cervical cancer compared to normal cells. Importantly, we demonstrated that the silencing of TrKB suppressed the activation of EMT via the downregulation of N-cadherin, vimentin, matrix metalloproteinase (MMP)2 and MMP9, and the upregulation of E-cadherin and tissue inhibitor of metalloproteinases (TIMP)2, which resulted in suppressed cell proliferation, migration and invasion. Furthermore, high phosphorylation levels of ERK and Akt were observed in the cervical cancer cells, while these levels were decreased in the cells in which TrKB was knocked down. On the whole, these findings suggest that the BDNF/TrKB pathway is a promising target for the prevention of tumor proliferation, invasion, metastasis and EMT in cervical cancer cells.

Association of codon 72 polymorphism of p53 with the severity of cervical dysplasia, E6-T350G and HPV16 variant lineages in HPV16-infected women

Purpose. Polymorphic variability in the tumour-suppressor protein p53 at codon 72 has a considerable impact on cervical cancer development. The present study clarified the association between p53 codon 72 genotypes and the risk of cervical disease in Greek patients. We also examined whether the presence of specific p53 genotypes in combination with HPV16 variants or E6 T350G sequence variation can modify an individual's susceptibility to cervical disease.Methodology. The analysis of p53 genotypes was performed through PCR-RFLP. Sequence and phylogenetic tree analyses of the HPV16 E6 gene were also performed in order to identify HPV16 variants and T350G sequence variation.Results/Key findings. The outcomes of the present analysis revealed that women who are homozygous for the arg genotype are at a 4.17-fold higher risk of developing HPV16-associated HSIL+ (OR=4.17, 95 % CI:1.48-4.9, P=0.0049). Moreover, p53 arg/arg patients infected by an HPV16 prototype strain were associated with an increased risk of more severe lesions, while a significant relationship between the p53 arg/arg genotype in patients with T350G sequence variation and the risk of high-grade squamous intraepithelial lesions (HSILs) was revealed.Conclusion. The oncogenic potential of the virus is increased by the presence of the p53 arg/arg genotype in the Greek population in such a way that the specific protein interaction E6 (L83V)-p53 (Arg-72) can modify an individual's susceptibility to cervical disease.

Notch is a critical regulator in cervical cancer by regulating Numb splicing

Cervical cancer, which is the second most common female malignancy, is characterized by the consistent presence of human papillomavirus. Inappropriate activation of Notch signaling has been associated with various types of cancer; however, the role of Notch in cervical cancer remains unclear. The present study aimed to investigate the role of Notch in cervical cancer. The methods used included the generation of plasmids, viability assays, polymerase chain reaction and western blotting The present findings demonstrated that cervical cancer samples also consistently exhibit abnormal activation of the Notch pathway. The data also indicated that different Numb isoforms may have opposite effects on the proliferation of cervical cancer cells. As a result, the activated Notch signaling pathway regulates the alternative splicing of the Numb gene, which affects the proliferation of the cervical cancer cells. These findings suggest that activated Notch signaling may lead to the development of cervical cancer by regulating Numb splicing. Thus, Numb splice variants may be a potential clinical marker for indicating cervical cancer genesis and development.

Influence of MDM2 polymorphisms on squamous cell carcinoma susceptibility: a meta-analysis

PURPOSE

Controversial associations between single-nucleotide polymorphisms (rs2279744, rs937283, rs3730485) of the MDM2 gene and the etiology of squamous cell carcinomas (SCCs) have been reported. This merits further comprehensive assessment.

MATERIALS AND METHODS

We systematically reviewed the available data and conducted an updated meta-analysis to evaluate the genetic effect of MDM2 polymorphisms in SCC susceptibility, using Stata/SE 12.0 software.

RESULTS

After screening, 7,987 SCC cases and 12,954 controls from 26 eligible case-control studies were enrolled. Overall, compared with the control group, a significantly increased SCC risk was observed for the MDM2 rs2279744 polymorphism in the Asian population (test of association: odds ratio [OR] 1.12, P=0.027 for G vs T; OR 1.26, P=0.016 for GG vs TT; OR 1.25, P<0.001 for GG vs TT + TG; and OR 1.08, P=0.023 for carrier G vs T). In subgroup analysis by SCC type, a similarly increased esophageal SCC risk was detected (OR 1.19, P<0.001 for G vs T; OR 1.46, P<0.001 for GG vs TT; and OR 1.48, P=0.005 for GG vs TT + TG). Furthermore, MDM2-TP53 double mutation was statistically associated with increased SCC susceptibility overall (OR 1.52, P=0.001), especially in the Asian population (OR 1.49, P=0.022). However, no significant difference between the control and case groups was obtained for MDM2 rs937283 or rs3730485 under any genetic model (all P>0.05).

CONCLUSION

Our results highlight a positive association between the GG genotype of MDM2 rs2279744 polymorphism and an increased risk of esophageal SCC in the Asian population, which needs to be clarified by more large-scale studies.

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

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 (P_trend = 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 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.

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.

Genetic susceptibility to cervical cancer: role of common polymorphisms in apoptosis-related genes

Cervical cancer is a common malignancy which poses a significant health burden among women, especially those living in the developing countries. Although human papillomavirus (HPV) infection has been unequivocally implicated in the etiopathogenesis of the cancer, it alone is not adequate to contribute to the malignant transformation of cervical cells. Most HPV infections regress spontaneously, and only a small proportion of women have persistent infections which eventually lead to malignancy. This suggests that interplays between HPV infection and other cofactors certainly exist during the process of cervical carcinogenesis, which synergistically contribute to the differential susceptibility of an individual to the malignancy. Undoubtedly, host genetic factors represent a major element involved in such a synergistic interaction, and accumulating evidence suggests that polymorphisms in apoptosis-related genes play an important role in the genetic susceptibility to cervical cancer. This review consolidates the recent literatures on the role of common polymorphisms in apoptosis-related genes in genetic susceptibility to cervical cancer.

Association of a miR-502-binding site single nucleotide polymorphism in the 3'-untranslated region of SET8 and the TP53 codon 72 polymorphism with cervical cancer in the Chinese population

OBJECTIVE

This study was conducted to identify whether polymorphic variants of set domain-containing protein 8 (SET8) and tumor protein p53 (TP53) codon 72, either independently or jointly, might be associated with increased risk for cervical cancer.

METHODS

We genotyped SET8 and TP53 codon 72 polymorphisms of peripheral blood DNA from 114 cervical cancer patients and 200 controls using the polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) and direct DNA sequencing.

RESULTS

The frequency of SET8 CC (odds ratios (OR) = 2.717, 95% CI=1.436-5.141) or TP53 GG (OR=2.168, 95% CI=1.149-4.089) genotype was associated with an increased risk of cervical cancer on comparison with the SET8 TT or TP53 CC genotypes, respectively. In additional, interaction between the SET8 and TP53 polymorphisms increased the risk of cervical cancer in a synergistic manner, with the OR being 9.913 (95% CI=2.028-48.459) for subjects carrying both SET8 CC and TP53 GG genotypes.

CONCLUSION

These data suggest that there are significant associations between the miR-502-binding site SNP in the 3'-UTR of SET8 and the TP53 codon 72 polymorphism with cervical cancer in Chinese, and there is a gene-gene interaction.

Application of human papillomavirus in screening for cervical cancer and precancerous lesions

Cervical cancer is a commonly-encountered malignant tumor in women. Cervical screening is particularly important due to early symptoms being deficient in specificity. The main purpose of the study is to assess the application value of cervical thinprep cytologic test (TCT) and human papillomavirus (HPV) detection in screening for cervical cancer and precancerous lesions. In the study, cervical TCT and HPV detection were simultaneously performed on 12,500 patients selected in a gynecological clinic. Three hundred patients with positive results demonstrated by cervical TCT and/or HPV detection underwent cervical tissue biopsy under colposcopy, and pathological results were considered as the gold standard. The results revealed that 200 out of 12,500 patients were abnormal by TCT, in which 30 cases pertained to equivocal atypical squamous cells (ASCUS), 80 cases to low squamous intraepithelial lesion (LSIL), 70 cases to high squamous intraepithelial lesion (HSIL) and 20 cases to squamous cell carcinoma (SCC). With increasing pathological grade of cervical biopsy, however, TCT positive rates did not rise. Two hundred and eighty out of 12,500 patients were detected as positive for HPV infection, in which 50 cases were chronic cervicitis and squamous metaplasia, 70 cases cervical intraepithelial neoplasia (CIN) I, 60 cases CIN II, 70 cases CIN III and 30 cases invasive cervical carcinoma. Two hundred and thirty patients with high-risk HPV infection were detected. With increase in pathological grade, the positive rate of high-risk HPV also rose. The detection rates of HPV detection to CIN III and invasive cervical carcinoma as well as the total detection rate of lesions were significantly higher than that of TCT. Hence, HPV detection is a better method for screening of cervical cancer at present.

Lessons and implications from association studies and post-GWAS analyses of cervical cancer

Cervical cancer has a heritable genetic component. A large number of genetic associations with cervical cancer have been reported in hypothesis-driven candidate gene studies, but many of these results are either inconsistent or have failed to be independently replicated. Genome-wide association studies (GWAS) have identified additional susceptibility loci previously not implicated in cervical cancer development, highlighting the power of genome-wide unbiased association analyses. Post-GWAS analyses including pathway-based analysis and functional characterization of associated variants have provided new insights into the pathogenesis of cervical cancer. In this review we summarize findings from candidate gene association studies, GWAS, and post-GWAS analyses of cervical cancer. We also discuss gaps in our understanding, possible clinical implications of the findings, and lessons for studies of other complex diseases.

Effects of MDM2 promoter polymorphisms on the development of cervical neoplasia in a Southeastern Brazilian population

We investigated the importance of two adjacent functional polymorphisms in the Murine Double Minute 2 (MDM2) gene, SNP285 G > C and SNP309 T > G, for the development of cervical lesions in a Southeastern Brazilian population (293 cases and 184 controls). MDM2 genotyping was performed by PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) and/or DNA sequencing. MDM2 SNP309 has potential as a biomarker of cervical neoplasia in non-smokers, patients with family history of cancer, or those who had late sexual debut (>16 years). Besides, this polymorphism may help identify women at risk of developing severe cervical lesion at a young age (<30 years).

MDM2 polymorphism associated with the development of cervical lesions in women infected with Human papillomavirus and using of oral contraceptives

Background

The MDM2 gene is the major negative regulator of p53, a tumor suppressor protein. Single nucleotide polymorphism in promoter region of MDM2 gene leads to increased expression resulting in higher levels of MDM2 protein. This event increases the attenuation of the p53 pathway. Polymorphisms in this gene can interfere in the regulation of cellular proliferation. We evaluated whether MDM2 SNP309 (rs2278744) associated or not with the use of oral contraceptive can heighten susceptibility to development of cervical lesions in women HPV infected.

Methods

MDM2 SNP309 (rs2278744) was genotyped in a total of 287 patients using the PCR-RFLP technique. The results were analyzed by UNPHASED v.3.121 and SNPStats programs.

Results

The three groups (SIL, LSIL and HSIL) showed no significant differences in either genotype or allelic frequencies for MDM2 polymorphisms, except when HSIL was compared with LSIL (p = 0.037; OR = 1.81). Furthermore, in the analysis of contraceptives, a significant association was found between the use of contraceptives and the MDM2 variant in the development of high-grade cervical lesions for the TG genotype (p = 0.019; OR = 2.21) when HSIL was compared with control. When HSIL was compared with LSIL (p = 0.006; OR = 2.27).

Conclusion

The results of this study suggest that MDM2 SNP309 might be a good marker for assessing the progression of LSIL to HSIL. In addition, they also show that oral contraceptives alone, did not have any effect on the progression or development of cervical lesions. However, they may act synergistically with MDM2 SNP309 (rs2278744) and HPV infection in the development of cervical lesions.

Association of TP53 codon 72 and intron 3 16-bp Ins/Del polymorphisms with cervical cancer risk

Cervical cancer incidence has grown worldwide, with it being a more significant problem in developing countries. Invasive squamous cell cervical cancers are preceded by a long phase of preinvasive disease, known as cervical intraepithelial neoplasia. Cervical cancer can develop when the virus takes advantage of any TP53 gene dysfunction of the host organism. TP53 is responsible for encoding the tumor suppressor p53 phosphoprotein, which helps preserve genome integrity. Currently, many studies have focused on genetic polymorphisms as an important contribution to cancer susceptibility, but few related to cervical intraepithelial neoplasia (CIN). Thus, the present study aimed to see whether patients with suspected CIN had TP53 gene polymorphisms that might have contributed to the development of neoplasia. This study included 133 women who were referred to the Cervical Pathology Clinic of the Maternity School Assis Chateaubriand MEAC for suspected cervical lesions. Polymorphism genotyping was carried out by the PCR-RFLP technique using DNA extracted from patients' blood. The most frequent genotype in both CIN(+) and CIN(-) patients was Arg/Pro TP53 codon 72 and A1A1 for 16-bp Del in intron 3. No risk of cervical cancer was found for the polymorphisms studied. However, a significant association was found when the two polymorphisms were combined: patients with the A1A1/ArgPro genotype were statistically more frequent in the CIN(-) group (p = 0.042), while A2A2-A1A2/ProArg was significantly more frequent in the CIN(+) group. The results of our study suggest that combined analysis of TP53 polymorphisms Arg72Pro and 16-bp Ins/Del may help to monitor the development of CIN in Brazilian women.

Evidence for an epistatic effect between TP53 R72P and MDM2 T309G SNPs in HIV infection: a cross-sectional study in women from South Brazil

OBJECTIVE

To investigate the associations of TP53 R72P and MDM2 T309G SNPs with HPV infection status, HPV oncogenic risk and HIV infection status.

DESIGN

Cross-sectional study combining two groups (150 HIV-negative and 100 HIV-positive) of women.

METHODS

Data was collected using a closed questionnaire. DNA was extracted from cervical samples. HPV infection status was determined by nested-PCR, and HPV oncogenic risk group by Sanger sequencing. Both SNPS were genotyped by PCR-RFLP. Crude and adjusted associations involving each exposure (R72P and T309G SNPs, as well as 13 models of epistasis) and each outcome (HPV status, HPV oncogenic risk group and HIV infection) were assessed using logistic regression.

RESULTS

R72P SNP was protectively associated with HPV status (overdominant model), as well as T309G SNP with HPV oncogenic risk (strongest in the overdominant model). No epistatic model was associated with HPV status, but a dominant (R72P over T309G) protective epistatic effect was observed for HPV oncogenic risk. HIV status was strongly associated (risk factor) with different epistatic models, especially in models based on a visual inspection of the results. Moreover, HIV status was evidenced to be an effect mediator of the associations involving HPV oncogenic risk.

CONCLUSIONS

We found evidence for a role of R72P and T309G SNPs in HPV status and HPV oncogenic risk (respectively), and strong associations were found for an epistatic effect in HIV status. Prospective studies in larger samples are warranted to validate our findings, which point to a novel role of these SNPs in HIV infection.

MDM2 SNP309 variation increases cervical cancer risk among Asians

MDM2 T309G polymorphism has been suggested to be a risk factor for a number of cancers. The association of MDM2 T309G genetic variation with cervical cancer risk remains inconclusive. In the present study, we aimed to get a more confidential result by conducting a quantitative meta-analysis. Relevant literature up to October 2013 was searched and screened. Essential information was rigorously extracted for data pooling and analyzing, and then, separate analyses on ethnicity and source of controls were also performed. As a result, four articles including five case-control studies were selected. The overall data failed to show a significant association between MDM2 T309G polymorphism and cervical cancer risk (GG vs TT: odds ratio (OR)=1.31; 95 % confidence interval (CI)=0.55-3.13; dominant model: OR=1.22; 95 % CI=0.65-2.31; recessive model: OR=1.45; 95 % CI=0.79-2.65). However, in the subgroup analysis about ethnicity, increased cancer risk could be shown among Asians (GG vs TT: OR=2.15; 95 % CI=1.03-4.51; recessive model: OR=2.01; 95 % CI=1.32-3.06). In conclusion, the results of the present study suggest that homozygous GG alleles of MDM2 T309G polymorphism might be a risk factor for cervical cancer among Asians. Further studies are needed get a more definitive conclusion.

P53 (Pro72Arg) polymorphism associated with the risk of oral squamous cell carcinoma in gutka, niswar and manpuri addicted patients of Pakistan

OBJECTIVES

The chewing habit of paan, chhaliya, and tobacco is common in the traditional culture of Pakistan. Currently, niswar, gutka and manpuri are also commercially available in the Pakistani market. Epidemiologic evidences and increased rate of oral squamous cell carcinoma (OSCC) cases may indicate a direct relationship of these chewing habits with oral carcinogenesis. The p53 gene has been known to be a tumor suppressor gene that is found mutated in common human cancers. The p53 gene contains a single nucleotide polymorphism at codon 72 of exon 4 which encodes either proline (Pro) or arginine (Arg). The aim of the present study was to investigate association of p53 gene codon 72 polymorphism with patients of oral squamous cell carcinoma consuming these carcinogenic chewable materials.

MATERIALS AND METHODS

Blood and tissue samples of 260 OSCC patients were collected with informed consent from the local hospitals of Karachi. The patients were compared with controls of similar age and sex. The exon 4 of p53 gene was examined by PCR-SSCP. The tumor samples showing mobility shift were purified and sequenced.

RESULTS

The C>G missense mutation at nucleotide position 215 of the coding sequence was identified which substitutes proline with arginine at codon 72 of p53 protein. When the data for CCC72CGC polymorphism was analyzed statistically, a significant difference was observed between OSCC and control samples. The Pro allelic frequencies were significantly higher in OSCC patients as compare to controls. The current study indicated the Pro form of p53 codon 72 increases the risk of developing OSCC in Pakistani population. The risk ratio for Pro allele was 1.5004 (95% confidence interval: 1.2559 to 1.7924) and odds ratio of Pro allele was 2.389 (95% confidence interval: 1.5591 to 2.8137) in comparison with the Arg and Pro alleles in the OSCC group.

CONCLUSION

These evidences suggest that there may be specific genetic targets with these chewing ingredients that are responsible for causing OSCC. The p53 codon 72 polymorphism is associated with OSCC at somatic cell level but the polymorphism was not associated at inherited level.