To determine whether human tumor cells secreted factors that suppress the expression of PPARγ and activation of its target genes, CD36 and FABP4, we collected CM from human mammary epithelial cells (HMECs) and two breast cancer cell lines, MDA-MB-468 (triple-negative) and BT474 (HER2+) and evaluated their activity on cultured ECs and pericytes. The gene discussed is CD36; the disease is breast cancer.