The loss of lipid content from the adipocytes in tumor stroma indicates that free fatty acids are released from these cells and transferred to the tumor cells, and this transfer of fatty acids from adipocytes to tumor cells via the adipose triglyceride lipase (ATGL)-dependent lipolysis pathway boosts tumor growth in vivo and in vitro, supporting the overexpression of pro-inflammatory cytokines and proteases, which leads to the activation of cancer-associated adipocytes (CAA) [156,157]. This evidence concerns the gene PNPLA2 and cancer.