Clinicohistopathological Features and Immunohistochemical Expression Patterns of p53 in Epithelial Ovarian Tumours: A Cross-sectional Study

Abstract

Introduction: Ovarian tumours represent 3% of female malignancies, with epithelial tumours constituting more than 90% of all ovarian cancers. Tumour suppressor gene 53 (TP53) mutations play an important role in the prognosis and treatment of ovarian cancer. The tumour suppressor gene Tumour Protein 53 (p53), located on the short arm of chromosome 17, acts by suppressing abnormal cell growth at the beginning of the Synthesis phase (S-phase) of the cell cycle. Previous studies have shown a correlation between p53 mutation or overexpression and patient prognosis in various types of tumours, including breast cancer, rectal cancer, intestinal cancer, lung cancer, and ovarian cancer. Aim: To investigate the clinicohistopathological features and immunohistochemical expression of p53 in Epithelial Ovarian Tumours (EOT). Materials and Methods: A cross-sectional study was conducted in the Department of Pathology at Hind Institute of Medical Sciences, Barabanki, Uttar Pradesh, India. The duration of the study was one year and two months, from September 2021 to November 2022. A total of 80 cases of EOT were included and histopathological diagnosis was performed, and immunohistochemical expression of p53 was evaluated in all cases. The Chi-square test was used to compare categorical data (the number of benign, borderline, and malignant EOT) and determine whether the difference in p53 expression (positive or negative) was statistically significant, using Statistical Package for the Social Sciences (SPSS) version 26.0. Results: The total of 80 cases of EOT in the present study comprised 56 (70%) benign, 5 (6.25%) borderline, and 19 (23.75%) malignant tumours. The p53 expression was statistically significant. Immunohistochemistry (IHC) for p53 showed diffuse strong positive nuclear staining (>60%) of the tumour cells in 14 cases, all of which were malignant epithelial tumours. Focally weak and patchy positive nuclear staining patterns (5%-60%) were observed in 64 cases, including 56 benign cases, four borderline cases, and four cases of malignant epithelial tumours, respectively. p53 positivity (<5% staining of tumour cells) was seen in two cases, one each of borderline and malignant epithelial tumour, respectively. Conclusion: The IHC marker p53 serves as a surrogate marker for p53 gene mutation, and its positivity is observed in serous EOT. Understanding p53 staining patterns can be used in conjunction with a panel of other antibodies to correctly classify morphologically confusing EOT. This can aid in assessing prognosis and understanding the biological behaviour of the tumour, which can be helpful in modifying the treatment plan.