Upregulations of specific pathway enzymes (i.e., PPAT, PAICS, and ATIC) in numerous cancers indicate an importance of purine metabolism and purinosomes in tumorigenesis (41, 90), while mutations of these enzymes affect purinosome assembly in cultured skin fibroblasts from patients with AICA-ribosiduria and ADSL deficiency (27). This evidence concerns the gene PPAT and cancer.