TYMS and neoplasm: Next, the correlation between uptake (FOLR1), activation (FPGS) and utilization (TYMS) was investigated by calculating a ratio between FOLR1 and TYMS as well as FPGS and TYMS. These ratios were calculated to determine the cellular throughput of the folic acid metabolism and associated significantly with tumor type (both p<0.0001, Figure 3B-3C).