Circulating levels of PCSK9, ANGPTL3 and Lp(a) in stage III breast cancers.

e12547 Background: Cholesterol plays an important role in sustaining tumor growth and metastasis in a large variety of cancers. New and powerful cholesterol-lowering drugs are being used in combination to treat cardiovascular diseases. As drugs directed against PCSK9 (evolocumab, alirocumab, inclisiran), ANGPTL3 (evinacumab) and Lp(a) (pelacarsen) are available, it becomes of interest to assess the circulating levels of these drug targets and their role in cancers. Our purpose here is to compare circulating levels of PCSK9, ANGPTL3, and Lp(a) in women with stage III breast cancer versus women with a premalignant or benign breast lesion. Methods: Twenty-three plasma samples from women diagnosed with a stage III breast cancer (ductal, lobular or mixed) were matched for age with twenty-three plasma samples from women bearing premalignant (stage 0, n=9) or benign (n= 14) breast lesions. Lipid profile (Apo B, total cholesterol, HDL and triglyceride levels) and Lp(a) were measured on a Roche Modular analytical platform. LDL levels were calculated with the Friedewald formula. ANGPTL3 and PCSK9 plasma levels were quantitated by ELISA. Difference between breast disease groups was deemed significant when group-comparison generated p-values < 0.05. Results: PCSK9 levels were significantly higher in women with stage III breast cancer compared to age-matched counterparts presenting a benign lesion (95.9 +/- 27.1 ng/mL vs. 78.5 +/- 19.3 ng/mL, p<0.05, n=14). Moreover, PCKS9 levels positively correlated with breast disease severity (benign, stage 0, stage III) (Rho=0.34, p<0.05, n=46). In contrast, ANGPTL3, Lp(a) or lipid plasma levels did not display any correlation with breast disease severity. Conclusions: In this cohort of 46 women, PCSK9 levels increased along with the severity of breast disease. Given that PCSK9 plays an important role in maintaining cholesterolemia and has been shown to degrade MHC-I on tumor cells, impeding immune T-cells response to tumors, confirmation of PCSK9 elevation in a larger cohort would pave the way for trials studying lipid-lowering drugs as adjuvant treatments in breast cancer.