Immunocytochemical expression of p16INK4a and HPV L1 capsid proteins as predictive markers of the cervical lesions progression risk.

Genital HPV infections are extremely common but most of them are spontaneously cleared by the host immune response. The main problem is how to identify the HPV-HR positive patients who are at risk of progressive disease. Aim: The purpose of this study was to investigate the uterine cervix lesions concerning the HPV status appreciated through the immunocytochemical expression of the L1 HPV and p16 INK4a proteins. Material and Methods: 76 women who tested positive for HPV were selected from a cohort of 374 patients. In this study were detected the immunochemical expression of HPV L1 capsid protein and p16 INK4a in LBC samples. Results: The p16 INK4a positive rate was expressed in 56.57% of all the cases. The percentage grew from 0% in NILM cases to 100% in SCCs cases (p-value <0.00001). The HPV L1 capsid protein positive was expressed in 12.50% of NILM cases, 33.33% of ASC-US, 50% of LSIL, 18.51% of HSILs cases, but 0% in the SCC group (p-value =0.01). The L1-/p16+ pattern was found in 21.87% of LSIL, 81.48% of HSIL, and 100% of SCC cases (p-value <0.00001). The association of these two markers (L1 and p16INK4a) raises the accuracy of the diagnostic from 64% for HPV L1 capsid protein and respectively 87% for p16I NK4a to 91% when they are associated. Conclusions: The combination of L1 capsid protein and p16 appears to be useful for an early diagnosis and may be able to identify the patients with risk of lesion progression.