Peng et al. also reported that EPI at a dose of 100 mg/m2 upregulated apoptosis while downregulating 5′-aminolevulinate synthase 2 (ALAS2) related to “glycine, serine, and threonine metabolism” in a subset of breast cancer patients, suggesting the role of these metabolic pathways in the development of symptomatic cardiomyopathy after EPI-based chemotherapy [62]. Here, ALAS2 is linked to breast cancer.