Our results on growth propensity to serine import are in line with recent findings demonstrating that either increased PHGDH expression or increased serine supply provide a proliferative advantage in breast cancer and melanoma.28 Corroborating these results, gene suppression of PHGDH rendered G55 cells susceptible to serine starvation under normoxia (Fig. 4b). This evidence concerns the gene PHGDH and breast carcinoma.