FABP4 and breast neoplasm: Indeed, prostate and breast tumor cells exposed to bone marrow adipocyte-derived factors via Adipo CM (Fig. 2D, E, and Supplementary Fig. 5) or transwell co-culture (data not shown) exhibit cytoplasmic lipid accumulation and highly upregulate fatty acid transporter CD36, fatty acid chaperone FABP4, and lipid droplet marker perilipin 2 (Fig. 2F).