RRM2 and neoplasm: In addition, the technical issues related to IHC assay with a possible impact on RRM2 assessment include antibody clones, staining patterns, scoring systems, and cutoff points, as these varied substantially between our studies and those of Xie et al. and Fisher et al. Standardization of staining and scoring protocols for RRM2 IHC along with its further testing in large cohorts that are evenly distributed in terms of tumor pathological features seem crucial to establish the clinical significance of RRM2 protein in pancreatic adenocarcinoma and other tumors as well.