EXPRESSION OF P16 PROTEIN IN SURFACE EPITHELIAL OVARIAN CARCINOMA & ITS ASSOCIATION WITH HISTOPATHOLOGICAL GRADING

Dr. Syeda Nabila Islam Juthee*, Dr. Mohammad Zillur Rahman, Dr. M Shahab Uddin Aahmad,
Dr. Sharmin Ashraf Rima, Dr. Purabi Sarkar and Dr. Rumana Mahmud

ABSTRACT

Background: Malignant ovarian tumors are the seventh most common female cancer and one of the leading causes of morbidity & mortality. In Bangladesh, ovarian cancer ranks as the 4th most prevalent cancer. Surface epithelial ovarian carcinomas are the most common malignancy of ovary which constitute more than 90%. Prognosis and treatment protocol for ovarian carcinomas are depend on histopathological grade. p16 is a tumor suppressor gene which is a negative cell cycle regulator. Several studies have linked the role of p16 protein in ovarian tumorigenesis. In ovarian carcinoma p16 is either deleted, downregulated, or overexpressed. p16 is overexpressed in high grade epithelial ovarian carcinoma in comparison to low grade carcinoma. Expression of p16 is directly proportional to grading of the tumor and which could be a potential target for therapy. Keeping this on mind we aimed to investigate the immunohistochemical expression of p16 in ovarian carcinoma and to assess its association with tumor grade. Materials and Methods: This cross-sectional study was conducted in the Department of Pathology, Chittagong Medical College, Chattogram from March 2019 to February 2021. Forty-five Haematoxylin and Eosin stained slides of ovarian carcinoma cases were evaluated to find out their histopathological type, grade. Immunostaining was done by using primary antibody against p16 (Rabbit monoclonal, dilution 1:100). Patient’s demographic data were collected and recorded in a predesigned data sheet. Statistical analysis was carried out as required. Ethical practice was ensured in every step of the study. Results: Among the 45 cases, the age range were 20-67 years (mean age was 46.42 years; SD 11.80). Majority of the tumors (n = 23, 51.11%) were diagnosed as serous carcinomas, 12 (26.67%) cases were diagnosed as endometrioid carcinomas, 10 (22.22 %) cases were diagnosed as mucinous cystadenocarcinomas. Seventeen (37.8%) cases were low grade and twenty-eight (62.3%) cases were high grade. Among the 23 serous carcinomas ,14 cases were high grade and 9 cases were low grade. Ten cases were diagnosed as mucinous cystadenocarcinomas and out of the them two cases were low grade and eight cases were high grade carcinoma. In case of endometrioid carcinomas, six cases were low grade and six cases were high grade. p16 score among 45 patients, 11 (24.4%) cases were negative and 34 (75.6%) cases were positive. Statistically significant association was found between tumor grades and p16 expression (p<0.05). Conclusion: This study found statistically significant association between histopathological grade and p16 expression (p<0.05). These findings may be helpful for selecting appropriate therapy for ovarian carcinoma patients.

Keywords: Malignant ovarian, malignancy, carcinoma patients, serous carcinomas, p16.