SPHK1 and breast carcinoma: Another study showed that, in breast cancer, SPHK1 and ceramide galactosyltransferase (UGT8) are highly expressed in ER-negative tumors, and dihydroceramide synthases (LASS4 and LASS 6), acid ceramidase (ACDase), and glucosylceramide synthase (GCS) are highly expressed in ER-positive samples (19).