PNPLA2 and cancer: In this review, we systematically summarize the critical role of LDs in cancer and then focus on four categories of lipid droplet-associated proteins having the most direct influence on LD biosynthesis (diacylglycerol acyltransferase 1 (DGAT1) and diacylglycerol acyltransferase 2 (DGAT2)), degradation (adipose triglyceride lipase (ATGL)), and two renowned protein families on the LD surface (perilipins and cell death-inducing DNA fragmentation factor alpha-like effectors (CIDEs)).