For instance, breast tumors generally tend to display high concentrations of taurine, choline, and glycine, the latter of which has been suggested as an erb-b2 receptor tyrosine kinase 2 (ERBB2)-associated marker of aggressiveness; also, serine auxotrophy, particularly in aggressive ER− or TNBC, has been observed [40, 44–46]. The gene discussed is ERBB2; the disease is breast neoplasm.