Expression of p16 in abnormal pap-tests as an indicator of CIN2+ lesions: a possible role in the low grade ASC/US and L/SIL (Ig) cytologic lesions for screening prevention of uterine cervical tumours.

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.