CDK9 and cancer: Many elongation factors and kinases participate in controlling the RNAP2 transcription pause release, a mechanism that regulates the expression of many genes involved in cancer progression and metastasis, like cyclin dependent kinase 9 (CDK9), v-myc myelocytomatosis viral oncogene homolog (MYC), Jumonji domain containing 6 (JMJD6), arginine demethylase and lysine hydroxylase and BRD4 [112,113,114,115,116].