4-((6-(Cyclohexylmethoxy)-9H-purin-2-yl)amino)benzenesulfonamide (NU6102, Figure 1) (Davies et al., 2002) is a low-nanomolar inhibitor of CDK2 (Ki CDK2 = 6 nM), but has a modest GI50 (8 μM) against human MCF-7 breast carcinoma cells. This evidence concerns the gene CDK2 and breast carcinoma.