Decreased expression of human papillomavirus E2 protein and transforming growth factor-beta1 in human cervical neoplasia as an early marker in carcinogenesis.

BACKGROUND AND OBJECTIVES

Human papillomavirus (HPV) is thought to be one of the possible causative factors in cervical carcinogenesis, and cervical carcinoma cells are refractory to tumor transforming growth factor (TGF)-beta1. The purpose of this study is to investigate the possible cause-effect association between HPV and TGF-beta1 during cervical tumorigenesis.

METHODS

We assessed the expression of HPV capsid proteins, HPV-16 E7, HPV-16 E2 (C and N terminals), TGF-beta1, and their receptors TGF-beta RI and RII by immunohistochemistry in 48 paraffin-embedded blocks of tumor tissue derived from patients of cervical neoplasia.

RESULTS

Expression of TGF-beta1 decreased as tumor cells progressed from cervical intraepithelial neoplasia (CIN)1, CIN2, CIN3, to microinvasive carcinoma (P < 0.05). Levels of TGF-betaRI and TGFbeta-RII stayed the same in all cases. HPV was found in 89.6% of the studied sections, and cervical lesions without HPV infection expressed significantly less TGF-beta1 (P < 0.05). By comparing the expression pattern of TGF-beta1 and HPV in the neoplastic cells with that of normal cervical epithelium in each section, we found loss of HPV-16 E2 higher in CIN3 (15/24) than in CIN1 or CIN2 (3/7), and there is a significant trend that loss of HPV-16 E2 expression correlated with a >50% loss of TGF-beta1 at the lesion site (P < 0.05).

CONCLUSIONS

Our result showed co-suppression of HPV and TGF-beta1 expression during progression of cervical squamous cell cancer. Using antibody against HPV-16 E2 may be an auxiliary tool for the investigation of cervical tumor progression.