Leptin Expression in High-Grade Serous Ovarian Carcinoma: The Controversy of Leptin Paradox in Ovarian Cancer

Abstract

Objectives: To analyse the characteristics and expression patterns of Leptin in High-grade serous epithelial ovarian carcinoma (HGSC), the most prevalent subtype of ovarian carcinoma, and to compare them with overall serous ovarian carcinoma population. Methods: A cross-sectional study was performed on a total of 77 paraffin-embedded HGSC tissue samples from patients over a period of 3 years. Immunohistochemical analysis was performed using a polyclonal Leptin antibody to samples. Data were analyzed using SPSS version 22.0. Results: Among HGSC patients, the majority (64.3%) were over 50 years old, and a significant portion (39.3%) were obese. Leptin showed a strong cytoplasmic expression in 69.6% of HGSC tumor cells and in 100% of LGSC tumor cells (p-value = 0.004). There was no correlation between lymphovascular space invasion and leptin expression. Interestingly, leptin expression in overall serous ovarian carcinoma patients exhibited a protective effect against metastasis (p-value = 0.047), suggesting a leptin paradox exists in this type of cancer. However, this association was no longer significant when the analysis excluded the LGSC group (p-value = 0.193). Conclusion: This study suggest that leptin expression is not a significant prognostic factor in HGSC. Comparison of HGSC with the overall serous ovarian carcinoma population reveals that the results of several previous studies were likely confounded by the inclusion of heterogeneous tumor morphologies within their samples. The presence of low-grade serous carcinoma within the population may have inadvertently led to the observation of a seemingly protective effect of leptin, a phenomenon sometimes referred to as the 'leptin paradox'.