[Expression of human papillomavirus 16 E7 DNA in patients with colorectal adenocarcinoma]

The relationship between Human papillomavirus (HPV) 16 infection and the natural course of colorectal adenocarcinoma has not been fully defined. In this study, the HPV 16 E7 DNA was detected in 82 patients with primary colorectal adenocarcinoma to study the relationship between HPV 16 infection and colorectal carcinoma. Samples were taken from both the tumors and the adjacent normal mucosa in the same patient. Polymerase chain reaction (PCR) was used to amplify the HPV16 E7 DNA fragment. The PCR products were gel-purified and sequenced for HPV genotyping. DNA sequence analysis indicated that PCR product was 297 bp. It was the equivalent of 562-858th pairs in the HPV 16 primitive sequences. Our results showed HPV16 E7 DNA expression was significantly higher in colorectal carcinoma (42/82) than in adjacent normal mucosa (4/82). The correlation was found between HPV16 E7 expression and tumor's location; the positive rate was 18.18% in the ascending colon carcinoma group and 64.10% in the rectal carcinoma group. High HPV16 E7 expression was also associated with lower Dukes stage (P < 0.01). These results indicated that there was correlation between colorectal adenocarcinoma and HPV 16 infection. HPV16 infection was relatively higher in the colorectal carcinoma and rare in the adjacent normal mucosa. Specimens expressing higher levels of HPV 16 E7 DNA were associated with lower Dukes stage and more distal location.