TNK2 and cancer: An enantiomer of piperazine-substituted chloropyrimidine, (R)-9b, has been identified as a potent inhibitor of Ack1 in vitro (IC50 = 56 nM, 33P HotSpot assay) and in vivo (IC50 < 2 μM, human cancer cell lines) and is stable in human plasma (half-life > 6h) [79].