Possible cofactor in cervical carcinogenesis: proliferation index of the transformation zone in cervicitis

Most cervical cancers arise from the transformation zone. Human papillomavirus (HPV) has been identified as playing a central role in cervical carcinogenesis. However, the lengthy period from initial HPV infection through the precancerous stage to cancer lesions implicates that the cofactors involved in the process might be random events. Our study was designed to study the relationship between the cell mitotic index and tissue inflammation of the uterine cervix. The results may help to explain the role of chronic inflammation as a possible cofactor of cervical carcinogenesis.

Using Ki-67 immunostaining, the proliferation index (PI) was determined in 30 cervices removed in hysterectomies for non-cervical diseases. The chronic cervical inflammation was graded according to quantification of inflammatory cells in adjacent stromal tissue. The relationships of these two parameters within the exocervix, the transformation zone (T-zone) and the endocervix were analyzed and their differences were compared.

A significant correlation between the microscopic inflammation scale and the PI was found in the T-zone of the cervix (p = 0.034). The PI of the T-zone, exocervix and endocervix were significantly different (p < 0.001) with scores of 66.1 (SD 26.3), 41.6 (SD 23.3) and 7.1 (SD 5.0), respectively.

The results, based on modern cellular evidence, explain, at least partially the observation that cervical cancer occurs predominantly in the T-zone and suggest that implementation of antibiotic treatment in selected human papillomavirus-infected patients might decrease the development of cervical cancer.