Background: Cervical cancer is one of the most common cancers that affect women worldwide. It is well established thathigh-risk human papillomavirus (HR-HPV) is the prime risk factor for the development of cervical cancer. Early and accuratediagnosis of cervical neoplasia is of utmost significance for prolongation of patient survival. A panel of immunomarkers hasbeen developed and tested to overcome the limitations to histopathological diagnosis. Among them p16 is one of the commonlyused immunomarkers now-a-days. In recent years, routine haematoxylin and eosin (H & E) stain coupled with p16immunohistochemistry (IHC) have a major impact in the field of uterine cervical pathology and cancer screening.

Objectives: The present study was aimed to determine the p16 scores and its association with histological types, and grades ofISCC including diagnostic accuracy in differentiating ISCC from CIN lesions.

Materials and Methods: This descriptive type of cross-sectional study was conducted in the Department of Pathology,Rajshahi Medical College (RMC), Rajshahi, in collaboration with the Department of Pathology, Bangabandhu Sheikh MujibMedical University (BSMMU), Dhaka, during a period of two years from January 2019 to December 2020 by using routine H& E staining and p16 IHC analysis to evaluate the expression of p16 in samples of cervical biopsies from 51 patients withhistopathologically confirmed diagnosed cases of CIN and ISCC, considering the percentage of p16 positive cells and thereaction intensity.

Results: This study revealed that the aberrant expression of p16 increased from LSIL to ISCC, thus emphasizing its usefulnessas an adjunct marker for predicting risk of developing cervical cancer in the test patients. Most of the cases of ISCC in this studyexpressed high level of p16, while only one patient with LSIL failed to express the marker. Notably, 90% of LSIL cases werelow to moderate p16 positive, 100% of HSIL cases were moderate to high p16 positive, while most of the ISCC cases (81%) hadhigh p16 expression. Among p16 positive cases, this is an attempt to verify direct association between lesion severity andreaction intensity. The frequency of positive cells and the reaction intensity were statistically significant (P<0.001) whencompared among different histologic types. Most importantly, the present results clearly demonstrated that p16 IHC wascapable of differentiating ISCC from CIN cases.

Conclusion: In addition to routine H & E staining and histopathological diagnosis of cervical lesions, p16 immunomarkercould be used for risk assessment of histologically detected lesions and for distinguishing between ISCC and CIN specimenswhich, in turn, could help predict the progression of cervical lesions and thus monitor the screening of cervical cancer in thecommunity.