The aim of this study was to assess the validity of protein p16 expression as an indicator of progression in lesions as ASC-US and L-SIL. For this purpose, we examined 246 cytological samples (91 ASC-US, 60 L-SIL, 36 ASC-H, 59 H-SIL) of which 151 were conventional Pap-tests (CC) and 95 in liquid based cytology (LBC) with colposcopic and histology follow-up. The results showed that in the positive p16 Pap-tests a 59% PPV vs CIN2+ in all cytologic diagnoses compared to 43% in cytologic reading alone. 96% of HG cytologic lesions were positive for p16, and the data showed good correlation between positivity for p16 in the cytologic preparations and the presence of CIN2+ lesions in the histologic test (chi-square for trend p < 0.0001). The sensitivity, specificity and NPV were 93%, 52% and 91%, respectively, in all cytologic diagnostic categories. P16 was positive in 46% of ASC-US and 53% of L-SIL. The PPV vs expressed CIN2+ was higher than that observed in cytologic reading (48% vs 26%, and 31% vs 20%, respectively). The sensitivity was 83%, the specificity 67% and 54%, respectively, and the VNP was 92% and 93%. It is possible to design algorithms for colposcopic follow-up that can reduce the need to obtain a follow-up. The future application of this test may allow the creation of a bio-molecular automated pap test.
