For example, a large study of high-grade serous ovarian cancer reveals human CDK12, the counterpart of yeast Ctk1 [51], to be a tumor suppressor [52]; CDK12 is also significantly mutated in prostate cancer [53] and in several other cancers (http://www.cbioportal.org/public-portal/). This evidence concerns the gene CDK9 and prostate carcinoma.