p16/Ki-67 dual staining in cervico-vaginal cytology: Correlation with histology, Human Papillomavirus detection and genotyping in women undergoing colposcopy

Abstract Objectives To evaluate the CINtec® PLUS assay (mtm laboratories), a new immunocytochemical method for the simultaneous detection of p16 INK4a and Ki-67, in liquid-based cervico-vaginal cytology, investigating the association of the dual staining with HPV infection and genotyping as well as cytological and histological abnormalities. Methods 140 women with a cervico-vaginal sample obtained immediately before the colposcopy were enrolled. This cytological sample was used for HPV testing with the Linear Array HPV Genotyping Test, the dual staining with the CINtec® PLUS kit and the morphology assessment. Results Cytology results were 38 NILM, 16 ASC-US, 32L-SIL, 54H-SIL or worse. 113 patients also had a colposcopy-guided biopsy, classified as 14 negative, 35 CIN1, 24 CIN2, 37 CIN3, 3 invasive SCC. A strong association between p16/Ki-67 and HR-HPV infection was found (COR=6.86, 95% CI: 1.84–31.14). Importantly, the association between p16/Ki-67 positivity and HPV16 and/or 18 infection was 2-fold stronger compared to that with the infection by other HR-HPV types (COR=9.92, 95% CI: 2.39–47.77 vs COR=4.20, 95% CI: 0.99–20.87). In addition, p16/Ki-67 positivity rate significantly increased with the severity of the cytological and histological abnormalities (p Conclusions This preliminary study evidenced that p16/Ki-67 immunostaining might have a relevant clinical role, since the dual staining was significantly associated with HR-HPV infection, particularly with HPV 16 and 18, and the increasing grade of the cervical lesions, the positivity for this biomarker being strongly related to the presence of a CIN2+ lesion.