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

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.

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.

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.

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.

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.