Viral genotypes and p53 expression in Epstein-Barr virus-associated primary malignant lymphomas of the intestines

A small number (4% to 6%) of primary malignant lymphomas arising in the intestines express the EBV genome. However, in these tumors, the viral genotype and the role of tumor suppressor gene p53 have not been investigated. We sought to determine what genotype of EBV is frequently involved and whether the expression of p53 is related to these tumors. We used EBER-1 in situ hybridization and polymerase chain reactions (PCRs) for EBNA-1, EBNA-2A, and EBNA-2B to detect latent infection with EBV and to determine the genotype, respectively. In addition, we performed p53 PCR-SSCP (exons 5 through 9) and immunohistochemical analysis for p53. We found that EBV type B was present in 4 of 6 cases (67%); the genotype of the remaining cases could not be determined. The p53 PCR-SSCP indicated normal migration patterns in all malignant lymphomas, despite the fact that the tumor cells were strongly immunostained for p53 protein in 5 of the 6 cases. Thus, our study demonstrates that EBV-associated non-Hodgkin's lymphomas of the intestines in Korea are strongly related to the type B EBV and not to mutations of p53 gene. We suggest that EBV-associated intestinal lymphomas may arise through an interaction between the latent proteins of EBV and the wild-type p53 protein.