Expression of p16 and ALK on Immunohistochemistry in patients with oral cavity squamous cell carcinoma in a tertiary care hospital

This study titled "Expression of p16 and ALK on Immunohistochemistry in patients with oral cavity squamous cell carcinoma in a tertiary care hospital" is a single centered, cross-sectional, observational study to be held at Department of Pathology and Lab Medicine, AIIMS Guwahati for a period of two years. The study aims to detect expression of p16 and ALK protein in oral cavity squamous cell carcinoma. After informed consent and filling up of the patient proforma, all oral cavity carcinoma samples received in the histopathology lab will be carefully collected, labelled, and left to fixate overnight in 10% neutral buffered formalin. The following day, these samples will undergo grossing, where  the representative tissue sections will be placed into individual cassettes for processing. These cassettes will then undergo dehydration, clearing, and wax impregnation in a tissue processor. The processed tissues will be embedded in molten wax for block preparation and sliced into 3–4-micron sections using a microtome, which will be then mounted onto slides. A total of eighty slides will be stained with haematoxylin and eosin (H&E) for histological grading and evaluation. Additionally, slides for immunohistochemistry (IHC) will be pre-coated with Poly-L-Lysine and stained with a specific mouse monoclonal antibody to p16. Carcinoma Cervix serves as the positive control, while staining without the primary antibody serves as the negative control. Microscopically normal appearing oral epithelial tissue sections expressing ALK protein will be used as positive controls for ALK staining. After xylene immersion, slides will be mounted with a coverslip using Dibutylphthalate Polystyrene Xylene (DPX). H&E, p16 and ALK IHC staining procedures will be carried out and mounted accordingly. Experienced pathologists will examine stained slides under a microscope, recording the extent and intensity of staining to provide quantitative and qualitative data on p16 and ALK expression. Representative fields will be captured in images for records and further analysis. The study does not involve any intervention or randomization. Confidentiality of subjects would be maintained as per ICMR Guidelines. Both Participant Information Sheet and Informed Written consent will be in English, Hindi and Assamese language (language preferred by the participant). The estimated sample size of the study is 80. Data analysis for the study will be conducted using SPSS version 29. Descriptive statistics such as mean (standard deviation, SD) or median (interquartile range, IQR) will be calculated for continuous variables. For categorical variables, including stage of cancer, histological grade, and p16 expression (categorized as positive or negative), ALK expression (categorized as positive or negative), frequencies and percentages will be used. The proportion of p16 and ALK positive cases will be expressed as a percentage with 95% confidence interval. The study involves less than minimal risk. There is no conflict of interest.