RRM2 and breast cancer: Numerous studies have demonstrated that elevated RRM2 expression correlates with poor survival outcomes and has been identified as a potential prognostic biomarker across various cancer types, including bladder cancer (Morikawa et al., 2010b; Zhou et al., 2022), colorectal cancer (Liu, X et al., 2013), cervical cancer (Wang et al., 2020), NSCLC (Souglakos et al., 2008; Hsu et al., 2011; Ma et al., 2020), breast cancer (Abdel-Rahman et al., 2022; Shi et al., 2022), and hepatocellular carcinoma (Qin et al., 2023).