Detection of HPV infection and gene mutation of adenomatous polyposis coli and K-ras and its significance in patients suffering from rectal cancer

Objective:To detect human papilloma virus(HPV)infection and adenomatous polyposis coli(APC)and K-ras mutation and elucidate their relationship with biological behavior of rectal cancer and the correlation between each other.Methods:The expression of HPV DNA in rectal cancer tissues and normal colonrectal tissues was detected using PCR method.The mutations in the MCR of APC gene and the exon-1 of K-ras were detected by PCR-SSCP method.All results were analyzed combined with the clinical pathological data.Results:The positive expression of HPV DNA was detected in 55 out of 75(73.3%)rectal cancer tissues but was not detected in normal mucosa tissues.HPV infection was related to the age of patients and lymph node metastasis,but not with the ethnic of patients,tumor size,gross type,histological classification,Duke's stage,and the depth of invasion.APC gene mutation was detected in 43(57.3%)cases and K-ras gene mutation was found in 34(45.3%).Both of them were not related with the age of patients,histological classification,the depth of invasion,lymph node metastasis,and Duke's stage.APC gene mutation was related with the gender of patients(P0.05).In 55 cases of HPV-infected rectal cancer tissues 31(56.4%)specimens had APC mutation and 24(43.6%)cases had K-ras mutation.In 20 HPV-negative rectal tissues 12(60%)cases had APC mutation and 10(50.0%)cases had K-ras mutation.In 43 cases with APC mutation,19(44.2%)cases showed K-ras mutation.In 32 tissues without APC mutation 15(46.9%)cases showed K-ras mutation.There was no correlation among HPV infection,APC mutation,and K-ras mutation.Conclusion:Our findings suggest that HPV infection was an important factor in the development of the neoplastic phenotype of rectal cancer.APC and K-ras mutations were the early molecular events that frequently occurred in colon carcinogenesis.