Background & objective: Except for the tight correlation to nasopharyngeal carcinoma, accumulating evidences show that Epstein-Barr virus (EBV) is correlated to other carcinomas. This study was to investigate the correlation of EBV to colorectal carcinoma in Chinese.
Methods: EBV DNA was detected by polymerase chain reaction (PCR) in 90 specimens of primary colorectal carcinoma and 25 specimens of corresponding adjacent non-cancerous tissue, with the primers covering 2 different regions of EBV genome, BamH I W fragment and latent membrane protein 1 (LMP1) exon 3. The expression of EBV nuclear antigen 1 (EBNA1) and LMP1 were determined by immunohistochemistry, and the expression of EBV-encoded RNAs (EBERs) was detected by in situ hybridization.
Results: EBV LMP1 exon 3 and W fragment were detected in 27.7% and 32.2% of the 90 colorectal carcinoma specimens, which were significantly higher than the positive rate of EBV gene in the 25 adjacent non-cancerous tissues (4.0%, P<0.001). Of the 29 W fragment-positive tumors, 23 (79.3%) were EBNA1-positive, 1 (3.4%) was EBERs-positive; most EBNA1-positive cells were tumor cells with positive signals gathered in the nuclei. No expression of EBNA1 and EBERs were detected in the 8 W fragment-negative tumors. No expression of LMP1 was detected in all tumor specimens.
Conclusion: EBV infection might be associated with colorectal carcinoma in Chinese.