Association between p53 Arg72Pro polymorphism and thyroid cancer risk: a meta-analysis

Analysis of Rare Alleles of miRNA-146a (rs2910164) and miRNA-34b/c (rs4938723) as a Prognostic Marker in Thyroid Cancer in Pakistani Population

Background: Rationale: The miRNAs are short non-coding functional RNAs that are involved in the regulation of transcriptomes. It was found that human miRNA-146a and miRNA34b/c are important microRNAs and are functioning either as onco-miRNAs, or acting as tumor suppressors, in different conditions. To date, no study has been performed to evaluate the alterations of miRNA-146ars2910164 and miRNA34b/crs4938723 polymorphism as a risk factor in the development of thyroid cancer in the Pakistani population. Mutational analysis of rs2910164 and rs4938723 of miRNA-146a and miRNA-34b/c was carried out to check their association with the development of thyroid carcinogenesis. Material and Methods: Papillary thyroid cancer (PTC) patients with age and gender-matched controls were recruited for the present study. DNA extraction, genotyping of rs2910164 and rs4938723 was carried out by ARMS-PCR. Statistical analyses were carried out using SPSS software (version 20). Results: The odds ratio for risk allele C of rs2910164 for patients and controls was 23.0168 (3.0321−174.7208) with a p-value of <0.0001, showing that the frequency of the major allele G was lower in patients while the frequency of minor allele C was higher in patients. Similarly, the odds ratio for risk allele C of rs4938723 was 1.8621 (1.0321−3.3596) with a p-value of <0.03788 showing significant association with the development of thyroid cancer. Conclusions: The study highlights the significant association of miRNAs SNPs as one of the genetic risk factor for PTC. It was concluded that miRNA-146a (rs2910164) showed higher frequency of minor allele C in patients. Similarly in miRNA-34b/c gene SNP rs4938723 was observed to have a strong association with the development of thyroid cancer as the frequency of rare allele C was higher in patients.

p53 p.Pro72Arg (rs1042522) and Mouse Double Minute 2 (MDM2) Single-Nucleotide Polymorphism (SNP) 309 Variants and Their Interaction in Chronic Lymphocytic Leukemia(CLL): A Survey in CLL Patients from Western Iran

Background: Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. The MDM2 and p53 are interacting proteins that play crucial roles in cell biology. Genetic variations of p53 and MDM2 have been identified in many cancers including CLL; among which are SNP309 in the promoter of MDM2 and SNP codon72 in p53. Materials and Methods: In this study, we sought to find the impact of two SNPs of p53 and MDM2 in the pathogenesis of CLL. A total of 100 CLL patients and 102 healthy controls were recruited. Genomic DNA was extracted, and genotyping was performed using the PCR-RFLP method. The allele and genotype associations were analyzed using the χ2 test. The gene-gene interaction analysis was studied using GMDR v0.9. Results: Our study found the absence of a significant difference between CLL patients and controls related to the allelic frequencies or genotypic distributions for both MDM2 SNP309 and p53 codon72. A significantly higher frequency of p53 C allele was found in patients with disease duration of more than 36 compared to those less than 36 months. However, GMDR analysis suggests genetic interaction between the genes under study. Conclusion: Our findings indicated each polymorphism of p53 codon72 and MDM2 (SNP309) was not a risk factor for CLL but the p53 C allele could be associated with the disease duration. Besides, the interaction between p53/MDM2 genotypes may confer susceptibility to CLL. Our study could be useful in genetic association studies of CLL and the role of gene-gene interactions in the susceptibility to the disease.

Frequency of somatic mutations in TERT promoter, TP53 and CTNNB1 genes in patients with hepatocellular carcinoma from Southern Italy

Somatic mutations in the TERT promoter and in the TP53 and CTNNB1 genes are considered drivers for hepatocellular carcinoma (HCC) development. They show variable frequencies in different geographic areas, possibly depending on liver disease etiology and environmental factors. TP53, CTNNB1 and TERT genetic mutations were investigated in tumor and non-tumor liver tissues from 67 patients with HCC and liver tissue specimens from 41 control obese subjects from Southern Italy. Furthermore, TERT expression was assessed by reverse transcription-quantitative PCR. Neither CTNNB1 mutations or TP53 R249S substitution were detected in any case. The TP53 R72P polymorphism was found in 10/67 (14.9%) tumors, but was not found in either non-tumor tissues (P=0.001) or controls (P=0.009). TERT gene promoter mutations were found in 29/67 (43.3%) tumor tissues but were not found in either non-tumor (P<0.0001) or control liver specimens (P<0.0001). The most frequent mutation in the tumors was the known hot spot at -124 bp from the TERT ATG start site (-124G>A, 28 cases, 41.8%; P<0.0001). A new previously never reported TERT promoter mutation (at -297 bp from the ATG, -297C>T) was found in 5/67 (7.5%) tumors, in 0/67 (0%) non-tumor (P<0.0001), and in 0/41 (0%) controls (P=0.07). This mutation creates an AP2 consensus sequence, and was found alone (1 case) or in combination (4 cases) with the -124 bp mutation. The mutation at -124 and -297 bp induced a 33-fold (P<0.0001) and 40-fold increase of TERT expression levels, respectively. When both mutations were present, TERT expression levels were increased >300-fold (P=0.001). A new TERT promoter mutation was identified, which generates a de novo binding motif for AP2 transcription factors, and which significantly increases TERT promoter transcriptional activity.

Pri-Mir-34b/C and Tp-53 Polymorphisms are Associated With The Susceptibility of Papillary Thyroid Carcinoma: A Case-Control Study

Tumor suppressor p53 directly regulated the abundance of the miR-34b/c. The interaction might contribute to certain cancer. We hypothesized that rs4938723 in the promoter region of pri-miR-34b/c and TP-53 Arg72Pro may be related to the risk of papillary thyroid carcinoma (PTC). A total of 784 patients with PTC and 1006 healthy controls were recruited to participate in this study. The variants were discriminated using a polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP). Additionally, the relative expression levels of miR-34b/c and TP-53 in 44 paired samples were revealed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). A significantly increased risk of PTC was observed in the miR-34b/c rs4938723 CT, CC, and CT/CC genotypes compared with the TT genotype (CT vs TT: adjusted odds ratio [OR] = 1.51, 95%confidence interval [CI] = 1.23-1.85; CC vs TT: adjusted OR = 1.89, 95%CI = 1.39-2.63; CT/CC vs TT: adjusted OR = 1.59, 95%CI = 1.30-1.92, respectively). Significantly increased PTC susceptibility was also associated with the TP-53 Arg72Pro CC and CG/CC genotypes compared with the GG genotype (CC vs GG: adjusted OR = 2.04, 95%CI = 1.54-2.70; CG/CC vs GG: adjusted OR = 1.35, 95%CI = 1.11-1.67, respectively). Stratification analysis revealed that patients carrying the TP-53 Arg72Pro C allele and CC genotype had a significantly increased risk for developing N1 (C vs. G: OR = 1.27, 95%CI = 1.03-1.56; CC vs. GG: OR = 1.62, 95%CI = 1.07-2.46, respectively). Combined analysis showed that the genotypes of rs4938723 CT/CC + TP-53CG/CC increased the risk of PTC compared with rs4938723TT + TP-53GG (OR = 2.25, 95%CI = 1.67-3.03). Additionally, level of miR-34b was significantly upregulated in PTC patients.These findings indicate that the miR-34b/c rs4938723 and TP-53 Arg72Pro polymorphisms may contribute to the susceptibility of PTC.

Association of p53 (-16ins-pro) haplotype with the decreased risk of differentiated thyroid carcinoma in Iranian-Azeri patients

Association of P53 polymorphisms with the increased risk of various cancers has been investigated in numerous studies. However, the results were conflicting and no polymorphism has been determined as a definite risk factor. It is likely that the study of P53 combined genotypes and haplotypes may be more useful than individual polymorphisms. Thus, in this study, we analyzed the associations of intron 3 Ins16bp and exon 4 Arg72Pro polymorphisms, as well as their combined genotypes and haplotypes with the risk of differentiated thyroid carcinoma in Iranian-Azeri patients. This case-control study was performed on 84 Iranian Azeri patients with differentiated thyroid carcinoma and 150 healthy subjects. Intron 3 genotype was determined using PCR products analysis on polyacrylamide gels and AS-PCR was used for genotyping Arg72Pro polymorphism. The javastat online statistics package software and SHEsis program were applied for data analysis. There was no significant difference in genotype frequencies of both two polymorphisms between cases and controls. However, the (-16 ins/-16 ins) (Arg/Pro) genotype combination had a noticeable but not significant association with decreased risk of thyroid cancer development (OR = 0.497 95%CI: 0.209-1.168 P = 0.080) and also the frequency of (-16 ins-Pro) haplotype was significantly higher in controls rather than patients (OR = 0.543 95%CI: 0.326-0.903 P = 0.018). In our study, there was association between (-16 ins-Pro) haplotype with decreased risk of differentiated thyroid carcinoma development in Iranian-Azeri patients.