RRM1 and lung carcinoma: Using Kaplan-Meier plotter, the present study showed that high expression levels of pyrimidine metabolic rate–limiting enzymes CAD, CTPS, DHODH, DTYMK, RRM1, RRM2, TK1, TYMS, and UCK2 were unfavorable prognostic markers in patients with lung cancer (Fig. 5a).