Detection of Human Papilloma Virus (HPV) Infection in Colorectal Cancer and Viral Genome Integration Status

Abstract

Background: Colorectal cancer (CRC) is the third common cause of malignancy in Iran, and its incidence rate has been raised due to an increase in individual and environmental risk factors. Objectives: The present study aimed to define the role of human papillomavirus (HPV) infection in CRC, then by drawing a phylogenetic tree, we aimed to analysis the sequences of isolated HPVs, and finally determine the viral genome physical status for HPV-16. Methods: A nested-PCR (nPCR), direct sequencing, and INNO-LiPA HPV genotyping assay were carried out for HPV detection, and a quantitative real-time PCR assay (qRT-PCR) was conducted for the physical status of the viral genome. Results: Among 157 subsets, there were 66 cases and 91 controls. Moreover, 5.7% (9/157) were HPV positive by nPCR, among whom 9.1% (6/66) were cases and 3.3% (3/91) were control groups (P = 0.750). The qRT-PCR analysis showed three forms of integrated, episomal, and mixed forms in our three HPV-16 strains. A higher rate of HPV infection was detected in the CRC cases; however, it was not statistically significant. Conclusions: Although there were limited positive results, higher ages (> 65) were related to HPV involvement and CRC outcome. Furthermore, 9.1% of the CRC cases were infected with HPVs. The HPV-16 genome integration is observed in high-grade cancer cases with severe malignancy in CRC patients.