In particular, through the manipulation of cellular Cer levels by overexpression, CerS 2, 4 or 6 in MCF-7 cells Hartmann’s group [92] highlighted that very long chain-Cer produced by CerS2 must be in equilibrium with long chain-Cer generated by CerS4 and CerS6 for normal cell growth, whereas the increase of CerS2, CerS4 and CerS6 detected in BC tissues and cells might be the physiological reaction of the tumor aimed at counteracting an imbalance between Cer species that promote and inhibit tumor cell growth. Here, CERS4 is linked to breast cancer.