ALDH5A1 and ovarian serous adenocarcinoma: Beside the sialyltransferases, other highly connected sphingolipid metabolism genes include ALDH5A1 (aldehyde dehydrogenase 5 family member A1), the reduced expression of which in high-grade serous ovarian cancer (HGSOC) causes the accumulation of hydroxybutyric acid (HBA) [30], and HEXA (hexosaminidase subunit alpha), the protein level of which was found to be increased among metastatic uveal melanoma [31].