RRM2 gene was higher expressed in male breast carcinoma, intraductal cribriform breast adenocarcinoma, invasive breast carcinoma, invasive lobular breast carcinoma, invasive ductal breast carcinoma, ductal breast carcinoma in situ, invasive ductal breast carcinoma epithelia, and ductal breast carcinoma patients, with respect to normal individuals. Here, RRM2 is linked to invasive breast carcinoma.