NOD1 and cancer: To uncover changes in sphingolipid metabolism upon perturbation of cellular homeostasis, primary human dermal fibroblasts (HDFs) were employed for two reasons: (i) Sphingolipid metabolism in cancer cells is dysregulated (Ryland et al,2011; Ogretmen, 2018) and (ii) NOD1 and NOD2 are strongly expressed in different sources of human primary fibroblasts (Uehara & Takada, 2007; Hirao et al,2009; Jeon et al,2012).