Role of immunomarkers (P16 and Ki67) in identifying pre-malignant and malignant lesion of cervix: a comparative study

Background: Cancer of the cervix is the second most common cancer among women worldwide. Although pap test has successfully reduced the incidence of cervical cancer, it is associated with high false positive and high false negative test results. In order to improve the efficacy of screening program, United States cervical cancer screening guidelines recommend use of combined testing (cytology + HPV-DNA) in women above 30-65 years of age. However, due to application of current HPV vaccines, cervical screening will face challenges due to declining trends in the prevalence of HPV genotypes covered by vaccines. Aim: The study is aimed at finding out the role of immunomarkers (P16 and Ki67) in identifying pre-malignant and malignant lesion of carcinoma cervix and their comparison with the co-testing (cytology + HPV-DNA) method of screening. Methods: A cross-sectional observational study was conducted on 32 cases after consent. The tests done were cytology + HPV-DNA, cytology+p16, cytology+ Ki-67 and were compared in terms of their sensitivity, specificity, positive predictive value and negative predictive value against the gold standard, histopathology. Result: Majority of cases were in 30-40 years of age group. The sensitivity, specificity, positive predictive value and negative predictive value of cytology + HPV-DNA testing was 94.44%, 50%, 77.27%, 83.33% while that of cytology + P16 was 88.88%, 60%, 80%, 75% and cytology + Ki-67 was 88.88%, 100%, 100%, 91.66% respectively. Conclusion: Ki67 immunomarker is a better screening tool in terms of specificity, positive predictive value and negative predictive value when compared to cytology + HPV/p16. Ki-67 can be considered as a potential screening tool in future for both vaccinated and unvaccinated population