Furthermore, the observation that CK2β modulates substrate specificity may be particularly important with respect to CK2-related disease pathology, as a high CK2α:CK2β ratio drives epithelial-to-mesenchymal transition in human breast cancer [10] and transgenic mice that over-express only CK2α in the mammary gland are more prone to adenocarcinomas than control litter mates [6]. This evidence concerns the gene CSNK2B and breast cancer.