Although the identified splicing factors were not differentially expressed between tumor and normal tissue or different breast cancer subtypes, we identified that RNA levels of downstream target sororin are highly correlated to proliferation markers in patient breast cancer tumors, suggesting that decreasing sororin levels after pladienolide B treatment or other pharmacological modulators of critical splicing factors could be a promising therapeutic avenue in the future treatment of breast cancer patients. This evidence concerns the gene CDCA5 and breast cancer.