TNF and melanoma: With a similar kinetic of the effect of TNF on the differentiation state of melanoma cells, extended analysis of the GO pathways indicated an increased activation of the ceramide and glycosylceramide biosynthetic process, along with a decreased activation of sphingolipid catabolic pathways upon TNF treatment, with the maximum effect observed at 24 hours and then a progressive decline at 48 and 72 hours (Supplementary Figure 4A).