RRM2 and renal cell carcinoma: Lu et al. (2012) established that RRM2 expression was relevant to depth of invasion, poor differentiation, and tumor metastasis in colorectal cancer. Studies have shown that RRM2 could regulate anti-tumor immune response, and RRM2 knockout could improve the anti-tumor efficiency of PD-1 blocker in renal cancer, implying that RRM2 may be a promising therapeutic target for renal cell carcinoma (Xiong et al., 2021).