PPARD and neoplasm: They accumulate in lipid droplets in tumor-associated macrophages (TAMs), providing a reservoir of PPARβ/δ ligands, and induce the upregulation of PPARβ/δ target genes associated with immune regulation and tumor progression, such as CD300A, mitogen-activated protein kinase (MAP3K) 8 and angiopoietin-like 4 (ANGPTL4) [471].