The desaturation of dihydroceramides to ceramides is mediated by dihydroceramide desaturase (DES).26 Pharmacological inhibition of DES activity with fenretinide has been demonstrated to increase the accumulation of endogenous dihydroceramides.27 Fenretinide has shown strong antitumor effects in various cancer settings and is currently tested in clinical trials.28–30 We supposed that fenretinide treatment phenocopied Cer (d18:0/24:0) or Cer (d18:0/24:1). This evidence concerns the gene DES and cancer.