Figure 5.

Expression of amino acid metabolism genes in ER⁺ breast cancer. A. Total RNA from 16 ER⁺ patients at NCKUH was used to analyze the mRNA expression levels by RT-qPCR. B. Schematic summarizing how amino acid metabolism-related signaling pathways regulate breast cancer development. Estradiol activates the estrogen receptor and further upregulates PHGDH, PSAT1, PSPH, and GLDC transcriptional expression via the serine-glycine pathway and may facilitate purine and pyrimidine synthesis. Meanwhile, active estrogen receptor can promote the degradation of methionine by MAT1A and further elevate S-adenosylmethionine (SAM), leading to DNA methylation.