AGXT and breast cancer: Since elevated SPT-mediated 1-deoxysphingoid levels were detected in serum samples from BC patients who received paclitaxel treatment, and a major dose-limiting toxicity for treatment with this drug has been shown [84], it has been suggested that the induction of the metabolic switch from SPT-dependent generation of 1-deoxysphingoid bases to conventional Spn by the use of L-serine can be a potential therapeutic intervention to alleviate paclitaxel-induced neurotoxicity [20,84].