Association of p53 codon 72 Arg>Pro polymorphism and risk of cancer in Iranian population: A systematic review and meta-analysis

Tumor protein 53 gene polymorphism, demographic attributes and associated risk factors among liver cancer patients in Calabar, Nigeria

Mutations in the TP53 gene had been attributed to the development of liver cancer. Hepatocellular carcinoma (HCC) and liver tumour are liver diseases having high mortality rates in several populations. There is no information on the TP53 gene polymorphism among liver diseases patients in Calabar, Nigeria. This study investigated the genetic polymorphism of TP53 among HCC and liver tumour in Calabar. This research was carried out in the University of Calabar Teaching Hospital, Calabar. Blood samples were collected from 35 clinically diagnosed hepatocellular carcinoma and 10 tumour patients and 10 healthy controls. DNA was extracted from all blood samples and Polymerase Chain Reaction (PCR) was performed using specific primers. The PCR amplicons were digested using Hae III restriction enzyme and the genotypic and allelic frequencies was determined. Demographic data among participants showed that males were 68.9% (31), females (31.1%; 14), sex ratio (2.2: 0.5), mean age was 41.51 ± 2.13 years with an odds ratio of 1.25. The distribution of participants according to marital status were 33(73.3%), 10(22.2%), and 2(4.4%) for married, single, and widowed respectively. The participants were from different extractions with varied representations of Yakurr (22.2%, 10), Efik (20%, 9), Boki (13.3%, 6), Ogoja (13.3%, 6), Annang (8.8%, 4), Ibibio (2.2%, 1) and Igbo (2.2%, 1) and respectively. Approximately, 64.7% (30) of the chronic liver diseases were from the Central and Northern part of Cross River State. The risk factors were HCV infection, HBsAg+, alcoholism, smoking, consumption of groundnuts that may have been contaminated with aflatoxin and family history of the disease. PCR product yielded 254 bp and digested PCR product showed homozygous TT mutation (27), heterozygous GT mutation (17) and homozygous GG wild type (1) in cases. The overall TP53 gene mutation frequency was 46.32% (44). The frequency of G allele, T allele, GG, GT and TT were 0.21, 0.79, 0.04, 0.33 and 0.62 respectively among cases, while GG (wild type) was only detected among controls in the study population. The genotypic and allelic frequencies conform to Hardy-Weinberg equilibrium meaning that the forces of evolution were not acting on the locus. There were significant differences in the genotypic proportions of the TP53 gene polymorphism among patients and controls. This study on the TP53 gene polymorphism will serve as baseline information on the molecular etiology of hepatocellular carcinoma and liver tumour in Cross River State.

Both p53 codon 72 Arg/Arg and pro/Arg genotypes in glioblastoma multiforme are associated with a better prognosis in bevacizumab treatment

BACKGROUND

It has previously been shown that bevacizumab, when added to chemotherapy, improved overall survival in several cancers. In glioblastoma multiforme (GBM), bevacizumab increased progression-free survival and it is widely used for tumor recurrence, though it has failed to improve overall survival (OS) in controlled trials. However, an effective biomarker for predicting the prognosis of bevacizumab treatment has yet to be identified. This study, therefore, aimed to retrospectively analyze the polymorphisms of p53 codon 72 and the clinical characteristics of GBM specimens from Taiwanese patients.

METHODS

The polymorphisms of p53 codon 72 in 99 patients with GBM treated at Taichung Veterans General Hospital in Taiwan from 2007 to 2017 were analyzed using direct DNA sequencing and PCR-RFLP analysis.

RESULTS

We found that among these GBM patients, the distribution of codon 72 polymorphisms was 28.3% for proline homozygotes (Pro/Pro), 38.4% for arginine homozygotes (Arg/Arg), and 33.3% for proline/arginine heterozygotes (Pro/Arg). Although the polymorphisms of p53 codon 72 were not directly associated with the overall survival of GBM, both the Arg/Arg and Arg/Pro genotypes were associated with significant benefits in terms of overall survival in patients treated with CCRT plus bevacizumab compared to patients treated with CCRT alone.

CONCLUSIONS

This pilot study suggests that both the Arg/Arg and Arg/Pro genotypes of p53 codon 72 polymorphism may have value as independent prognostic or predictive parameters for bevacizumab treatment response and failure. Relatedly, the results of the study further demonstrate the utility of stratifying GBM patients according to bevacizumab sensitivity.