There has been no attempt to apply protein-based markers of exfoliated cervical cells (ECCs) for primary screening of cervical cancer. In the present study, the levels of six tumor-associated protein [TAPs: Sialyl Lewis A (SLeA), Cancer Antigen 15-3 (CA 15-3), p53, heat shock protein (Hsp)70, Hsp27 and squamous cervical carcinoma antigen (SCCA)]and of two human papillomavirus (HPV) viral proteins (HPV16 E7 and HPV16 L1) of ECCs lysates were evaluated by enzyme-linked immunosorbent assays (ELISAs).The wells of 96-well plates were coated with the ECCs lysates from normal, cervical intraepithelial neoplasia (CIN) I, CIN II, CIN III and cancer groups, and candidate proteins were detected by relevant antibodies. SLeA level decreased with increasing severity of lesions, whereas the levels of other candidate proteins increased. SLeA, HPV16 L1 and p53 levels appeared more useful for detecting cervical lesions than the other candidates. The combination of ELISA-SLeA and ELISA-HPV16 L1 could efficiently detect cervical lesions from normal. The combination of ELISA-SLeA and ELISA-p53 could powerfully discriminate cancer from normal with 91.3% sensitivity and 96.7% specificity. The protein levels of ECCs have great potential as biomarkers for primary screening of cervical cancer.
Keywords: Cervical cancer; Exfoliated cervical cell; Human papillomavirus; Pap test; Tumor-associated protein.