p16iNK4a as a complementary marker of high-grade intraepithelial lesions of the uterine cervix. I: Experience with squamous lesions in 189 consecutive cervical biopsies

Summary Aim To test the usefulness of p16 INK4a immunostaining for improving the diagnostic accuracy of cervical punch biopsies referred to a routine laboratory setting during the investigation of women with abnormal Papanicolaou smears. Methods A total of 188 consecutive and unselected colposcopically directed cervical biopsies and a single contemporaneous cervical polyp were accessioned prospectively over a 3-month period, step-serially sectioned and examined by HE cervical intraepithelial neoplasia [CIN] 2-3), 27 (14.3%) showed a low grade squamous intraepithelial lesion (HPV +/- CIN1) and 85 (45%) showed a range of non-dysplastic (inflammatory or reactive) changes. Diffuse strong parabasal immunostaining for p16 INK4a , suggestive of integrated high-risk HPV DNA into the host genome, was observed in 81 biopsies (42.9%, including the cervical polyp) and correlated (>90%) with HGSIL in the HE i.e., the discriminatory watershed between continued surveillance and active intervention.