Up-regulation of Foxp3 participates in progression of cervical cancer.

Foxp3 was identified as a key protein in mediating inhibitory functions of regulatory T cell (Treg). Foxp3 was thought to express only in the T cell lineage until recently when some researches reported that Foxp3 was also expressed by cancer cells. In this study, we describe for the first time the expression of Foxp3 in cervical cancer. Progression from cervical intraepithelial neoplasia (CIN) to cervical cancer is a multistep process initiated by persistent infection with high-risk human papillomavirus (HPV). P16(INK4a) is a crucial marker of HPV integration into host cells. In the present study, expressions of Foxp3 and P16(INK4a) in CIN and cervical cancer were detected by immunohistochemistry. Our results found expression level of Foxp3 was increased during the progression of cervical neoplasia. Moreover, up-regulation of Foxp3 appeared to be correlated with the expression of P16(INK4a). Examination of the role of Foxp3 in differentiation by double immunostaining for cytokeratin 10 (CK10) showed significant association between Foxp3 expression and differentiation (Foxp3 vs CK10). Furthermore, positive expression of Foxp3 was correlated with tumor size. These data suggest that Foxp3 may play an important role in differentiation and growth of cervical cancer cells. Our findings provide new insights regarding the role of Foxp3 in differentiation and its association with HPV infection during the development of cervical cancer.