This shift is associated with hypoxia-driven formation of lipid droplets containing triacylglycerols and cholesterol esters54, with concomitant decrease in free fatty acid concentration in plasma55 and tumor tissues56 stemming from attenuated expression of lipolytic enzymes such as adipose triglyceride lipase (ATGL), encoded by PNPLA257. This evidence concerns the gene PNPLA2 and neoplasm.