Additionally, several pieces of evidence have revealed that LDs of different cancer cells displayed an increase in proteins also involved in tumorigenesis, such as PI3K, extracellular signal-regulated kinase 1 and 2 (ERK1 and ERK2), caveolins, and cyclooxygenase 2 (COX-2) for prostaglandin E2 (PGE2) production [4,60,61,62,63]. Here, PTGS2 is linked to cancer.