In this study, by combining RNA-seq and clinicopathologic data from Oncomine and TCGA (Figures 2, 3), we found that expression of RRM1 and RRM2 genes were both significantly increased and correlated with higher TNM stages in most common types of cancers and demonstrated a tumor-promoting role for the RRM1-RRM2 holoenzyme. Here, RRM1 is linked to cancer.