a, differences in the central carbon metabolism of a cell in a quiescent state compared to a proliferating cell; b, diverse biosynthetic outputs of central carbon metabolism. RTK, receptor tyrosine kinase; GLUT1, glucose transporter 1; PKM2, pyruvate kinase M2; ACSS2, acetyl-CoA synthetase 2; LDH-A, lactate dehydrogenase A; PDH, pyruvate dehydrogenase; PDK1, pyruvate dehydrogenase kinase 1; ACLY, ATP-citrate lyase; MCT1, monocarboxylate transporter 1; ASCT2/SN2, glutamine transporter.