The expression of RPN2 is positively correlated with the progression of breast cancers (Ono et al., 2015), non-small cell lung (Fujita et al., 2015), gastric (Fujimoto et al., 2018), esophageal (Li et al., 2019), and colorectal cancers (Bi and Jiang, 2018), whereas TUSC3 was reported as a candidate tumor suppressor (Vašíčková et al., 2018). This evidence concerns the gene RPN2 and breast cancer.