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

Abstract

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.

Keywords: Hepatocellular carcinoma; Liver tumour; Mutations; Patients; Tumor protein gene.

Fig. 1

Electropherogram showing TP53 gene amplicons of 254 bp using 1000 bp ladder D = DNA ladder; Lanes 1 and 3 for control samples. Lanes 4–9 = HCC samples. Lanes 10–16 = Liver tumour samples. The control samples show monomorphic bands, while the HCC and Liver Tumour samples show polymorphism at this gene size of 254 bp

Fig. 2

Electropherogram showing Hae III digest of TP53 gene amplicons on exon 7. Legend: Lane 1 = DNA ladder 1500 bp; Lane 2 = Silent mutation. Lane 3–11: = Missense mutations (GT) having uncleaved 158 bp, 92 bp and 66 bp fragments. Lane 2 is control group; Lane 3–7 = HCC patients; Lane 8–11 = Liver Tumour patients