Although this study did not analyze the intracellular lipid metabolism of FFAs, several studies have reported increased lipid metabolism during hypoxia.27,28 Bensaad et al. reported that transcriptional regulation of fatty acid-binding proteins (FABP) 3 and FABP7 in glioma and breast cancer cells is induced by HIF-1α and leads to a significant lipid droplet (LD) accumulation during hypoxia.29 They demonstrated that triglycerides contained in LDs are degraded to generate FFAs when the cells need to produce ATP via FAO. Here, FABP7 is linked to breast cancer.