Abstract:

Objective To explore p53 gene mutation and expression in hepatocellular carcinoma （HCC） in the presence of both hepatitis B virus （HBV） and aflatoxin B₁ （AFB₁）. Methods A total of 82 patients from Guangxi province with HCC were divided into four groups based on their HBV and AFB₁ status：HBV（+）/AFB₁（+） （n=44），HBV（+）/AFB₁（-）（n=15）， HBV（-）/AFB₁（+） （n=15），and HBV（-）/AFBB₁（-）（n=8）. As an additional control group，hepatic tissues from 20 patients with liver trauma or hepatic hemangioma were analyzed. PCR and immunohistochemistry were used to examine 11-pairs exons of p53 mutations and expression of p53 protein. Results The rate of patients showing mutations in p53 exon7-249 among all 82 study participants with HCC was 40.2%；the rates in each HCC group were as follows：HBV（+）/AFB₁（+），50.0%；HBV（+）/AFB1（-），13.3%； HBV（-）/AFB₁（+），46.7%；and HBV（-）/AFB₁（-），25.0%. None of the non-HCC controls showed mutations in this exon. The mutation rate was significantly higher in the HBV（+）/AFB₁（+） group than in the HBV（++）/AFB₁（-） group （P<0.05）；differences among the rest of the HCC groups were not significant（P>0.05）. Rate of tissue positivity for p53 protein was 74.4% among all 82 patients with HCC；the rates in individual groups were as follows：HBV（+）/AFB₁（+），90.9%； HBV（+）/AFB1（-），46.7%；HBV（-）/AFB₁（+），73.3%；and HBV（-）/AFB₁（-）， 37.5%. The rate of protein positivity was 0 among non-HCC controls. Rate of p53 positivity was significantly higher in the HBV（+）/AFBB₁（+） group than in the HBV（+）/AFB₁（-） and HBV（-）/AFB₁（-） groups （P<0.05）. No significant differences were observed among the rest of the HCC groups（P>0.05）. Generally，mutation in p53exon7-249 positively correlated with p53 protein expression（P<0.05）.Conclusions Among patients with HCC from Guangxi province，p53 mutation and expression are prevalent， and p53 exon7-249 appears to be a mutational hot spot in this part of China. The high rate of p53 mutation and high p53 expression may be related to the synergy of HBV and AFB₁ exposure in this region.

Key words: Liver neoplasm, Hepatitis B virus, Aflatoxin B₁, p53, Mutation