CEACAM5 and obesity due to melanocortin 4 receptor deficiency: A multi-marker panel was developed using ELISA or electrochemiluminescence immunoassay to measure the levels of FTO (fat mass and obesity-associated protein), PIK3CB (phosphatidylinositol-4,5-biphosphate 3-kinase catalytic subunit β), CEA, and CA15-3 in patients with stage I–II breast cancer [35].