Abstract 5169: Circulating levels of ANGPTL3, PCSK9, apoCIII and lipoprotein (a) in high-grade serous ovarian cancer

Abstract Background: Ovarian cancers require abundant amounts of lipids for their growth. Recent years have highlighted the role of ANGPTL3, PCSK9, ApoCIII and Lp(a) as key players in lipid metabolism. But circulating levels of these factors in ovarian cancers have not been thoroughly investigated to date. Objective: We assessed the profiles of plasma ANGPTL3, PCSK9, ApoCIII and Lp(a) in ovarian high-grade serous carcinoma (HGSC). Methods: Plasma samples collected from women diagnosed with an HGSC (n=31) or a benign ovarian lesion (BOL, n=40) were analyzed for plasma lipid profile (ApoB, total cholesterol, HDL, triglycerides, Lp(a) levels) on a clinical modular platform (Roche). ApoCIII, ANGPTL3 and PCSK9 levels were measured with commercially-available ELISA kits. Differences between HGSC and BOL were assessed by two-group comparisons. Pairwise correlation strength between variables was evaluated with Spearman’s rank order tests. Logistic regression modelling was used to further examine the associations between selected variables and HGSC diagnoses. Results: ANGPTL3 levels increased in HGSC (84.1 ng/ml, SD=29.2ng/ml, n=31) compared to BOL (66.9ng/ml, SD=30.7 ng/ml, n=40; HGSC vs BOL p=0.02). Receiver operating characteristic (ROC) curve suggested that plasma ANGPTL3 levels were moderately associated with HGSC (AUC=67.7%, p=0.005 1) and did not increase predictive performance of ovarian tumor biomarkers CA125 and HE4 in multivariable model. Associations between ANGPTL3 levels and cholesterol (HDL, non-HDL, LDL and total) could be observed in the control group but not in the HGSC group. The same dissociation was observed for the inverse correlation between HDL and triglycerides in HGSC. Furthermore, moderate associations were observed between PCSK9 & CA19-9 in the entire cohort (rho=0.34, n=53, p=0.013) and Lp(a) & CA125 in HGSC cases (rho=0.51, p= 0.017). Conclusion: In this cohort of 71 women, we report increased levels of ANGPTL3 in HGSC with an effect size (Cohen’s D) of 0.57. Confirmation of this result in larger cohort studies (minimal n>50 in each group) would warrant further investigation into the roles of circulating ANGPTL3. Its inhibition may allow to tackle deregulated lipid metabolic pathways contributing to ovarian cancer progression. Citation Format: Emilie Wong Chong, France-Hélène Joncas, Pierre Douville, Dimcho Bachvarov, Frédéric Calon, Nabil Seidah, Caroline Diorio, Anne Gangloff. Circulating levels of ANGPTL3, PCSK9, apoCIII and lipoprotein (a) in high-grade serous ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5169.