CDK20 and hepatocellular carcinoma: The human CCRK gene, encoding for CDK20, is in general widely expressed throughout human tissues, with a prominent presence in the brain, lung, kidney, and gastrointestinal tract.232 In human hepatocellular carcinoma (HCC) cells where CCRK transcription and protein expression are increased by direct binding of the androgen receptor (AR) to the androgen-responsive element within the CCRK promoter.