HPV16 AND EXPRESSION OF PROTEIN P16INK4A AND E7 ONCOPROTEIN IN COLORECTAL CARCINOMA.

OBJECTIVE

Human papillomavirus (HPV) is the agent of the most prevalent sexually transmitted diseases in the world associated with cervix and anal canal cancer. The action of HPV on colorectal carcinogenesis is not yet established. This research aimed to study the possible correlation between the presence of HPV16 and the gene expression of p16INK4a protein and HPV E7 oncoprotein and their levels in colorectal carcinoma tissue.

METHODS

A retrospective case-control study of 79 patients with colorectal carcinoma was divided into two groups: HPV-positive and HPV-negative. The polymerase chain reaction was performed, in addition to dot-blot hybridization for HPV16 and HPV18. Colorectal tissue samples were also subjected to immunohistochemical study to assess the tissue level of E7 and p16INK4a proteins.

RESULTS

HPV was identified in 36 (45.6%) cases. There was no significant difference between groups regarding gender (p=0.056), age (p=0.1), colic and/or rectal location (0.098), and presence of HPV. Gene expression of HPV E7 oncoprotein was present in 3.12% of cases (p=0.9), and p16INK4a protein expression was observed in 46.3% (p=0.27) of those selected with HPV detection.

CONCLUSION

Gene expression and tissue levels of E7 oncoprotein and p16INK4a protein found in HPV-positive patients suggest the absence of HPV16 oncogenic activity in colorectal carcinoma.