MYC and neoplasm: The upregulation of serine and glycine biosynthesis were observed both in various tumor types [25], [26], [27], [28], [29] and mitogen-activated normal lymphocytes [36], and serum stimulation of Rat1A fibroblast proliferation resulted in an increased 13C-labeled glycine derived from 3-phosphoglycerate, in a myc dependent manner [37].