Dinaciclib (SCH 727965, Merck) is a pyrazolo [1,5-α]pyrimidine that potently inhibits CDK1, CDK2, CDK5, and CDK9 (Parry et al., 2010; Paruch et al., 2010) with IC50 values ranging from 1 to 4 nM in a broad spectrum of human cancer cell lines including MCL, NHL, leukemia, colon, pancreatic, breast, prostate, SCLC, liver, and bladder (Parry et al., 2010). The gene discussed is CDK9; the disease is cancer.