| Infection with human papillomavirus (HPV) is associated with the development of cervical cancer, but whether HPVs play a role in colorectal cancer (CRC) or the virus can be transmitted via blood remains controversial. To investigate the HPV prevalence in patients with CRC and to detemine whether HPV can be transimitted via blood and whether HPV DNA in peripheral blood can be a biomarker for diagnosis of HPV-related CRC, paired tumor tissue, tumor-adjacent tissue and whole blood samples from 96 CRC patients and 48 whole blood samples from healthy blood donors were collected. HPV was detected by consensus nested PCR and HPV genotypes were determined by reverse southern blot and pyrosequencing. HPV DNA was detected in 32 patients with colorectal cancer (33.3%). Among them, 28 (29.2%) were detected in tumor tissues, three (3.1%) were detected in tumor-adjacent tissues, four (4.2%) were detected in peripheral blood. We found 6.3% (3 of 48) were positive for HPV DNA in the peripheral blood samples of healthy donors. HPV 16 was the most frequently viral type, being present in 32 out of 35 (91.4%)HPV positive patients. The other HPV types were HPV18, HPV51 and HPV59. Three HPV positive donors were all detected HPV16. The HPV prevalence in tumor tissues was much higher than in tumor-adjacent tissues (P<0.001), so we thought HPV infection may be a risk factor for colorectal cancer. The HPV prevalence in peripheral blood of the patients and the donors had no statistical difference, so our conclusions were detection of HPV DNA in peripheral blood may not reflect the HPV status of colorectal cancer, but the detection of HPV DNA in peripheral blood suggested that HPV may be transimited via blood.To study the role HPV16 E6 gene plays in colorectal, we construct pEGFP-HPV16 E6 fusion gene in eukarytic expression vecter, as a preparation for the mechanism study. We also designed a real-time fluorescence quantitative PCR method using MGB probes to quantitate HPV16 and 18 meanwhile.
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