RBP4 and breast carcinoma: Interestingly, MRAS highlighted Esrp2 as the master regulator under kidney cell development (Figure 5D; Figure S5F and Table S5, Supporting Information), aligning with the recent finding that Esrp2 regulates isoform switching of epithelial‐associated proteins in kidney development.[58] The second application is to investigate the splicing changes in breast cancer cell transformation by single‐cell RNA‐seq data from breast cancer patients.[59] Here, we observed numerous abnormal splicing events and significant changes in RBP expression at the single‐cell level of breast tumors.