We also found that HCC tissues expressing the 3-PGA binding-defective PHGDH mutants (via AAV) in the background of wild-type PHGDH expression that maintains serine synthesis showed a strong elevation of apoptosis even in peripheral areas with relatively high glucose, while the PHGDH mutants constitutively bound to 3-PGA prevented apoptosis in central areas, even under CR. Here, PHGDH is linked to hepatocellular carcinoma.