Possible mechanism and significance of rare p53 mutation in Epstein-Barr virus-associated gastric cancer / 中国肿瘤临床

ABSTRACT

In 2014, The Cancer Genome Atlas firstly classified gastric cancer into four types according to genotype. Epstein-Barr virus (EBV) positive gastric cancer or EBV-associated gastric cancer (EBVaGC) is attracting attention because it is a possibly suitable group for immunotherapy. Among the mutations observed in tumors, such as gastric cancer, p53 mutations are the most frequent. In particular, it occurs more frequently in EBVaGC than in EBV-negative gastric cancer (EBVnGC). Meanwhile, EBV infection is considered as an early event of tumorigenesis. The interactions between wild-type p53 proteins and BZLF1 (Z) proteins are essential in maintaining the latent state of EBV infection and promoting early replication. In the latter stages of replication, wild-type p53 proteins are degraded through the ubiquitination of some viral molecules. These findings may indicate the importance of wild-type p53 genes in EBVaGC formation. Inflammatory responses induced by EBV infection, tumor with a large number of lymphocyte infiltration, genome high mutation, and PD-L1 amplification make it possible to become the appropriate group of immunotherapy, which also illustrate that the important role of immune microenvironment during tumor progression. In EBVnGC, extremely high levels of p53 mutation were observed because of several associated factors, and the p53 protein encoded by the mutant p53 gene lost its antitumor function after tumorigenesis. In this review, the possible mechanisms of rare p53 mutation in EBVaGC are summarized.