Objective To investigate the expression of RCAS1 in the tissues of normal cervix,cervical intraepithelial neoplasia(CIN)and cervical cancer,and to explore their role in the pathogenesis of cervical carcinoma.Methods The expression of RCAS1 protein was analyzed by immunohistochemical S-P method in 89 cases of cervical carcinoma,82 cases of CIN,and 24 cases of normal cervical specimens.Results Immunohistochemistry showed that the expression rate of RCAS1 in normal cervix,CINⅠ,CINⅡ-Ⅲ and cervical cancer were 0.00,0.314,0.447 and 0.775,respectively.RCAS1 expression tended to increase along with tumor progression.The expression of RCAS1 in cervical cancer was significantly related to the histological grade,the tumor in different sizes(≥4cm or 0.05)betwan patients' age,clinical stage and histological classification.Conclusions The data suggested that RCAS1 might play an important role in the pathoqenesis and development of cervical carcinoma.Over expressed RCAS1 could be regard as an important parameter in malignant degree and poor prognosis of cervical cancer.