A sphingolipid found in the stratum corneum of human skin; found in higher concentrations in female sebum compared to male sebum; levels positively correlate with cytotoxicity in CCRF-CEM, MOLT-4, COG-LL-317h, and COG-LL-332h T cell ALL cell lines; levels increased by 149.49-fold in DEGS1 knockdown UM-SCC-22A human head and neck squamous carcinoma cells in vitro; levels are also increased in INS-1 β-cells incubated with glucose and palmitate