BRD4 and cancer: While JQ1 by itself showed IC50s in the micromolar range (2.5 μM to >10 μM) in majority of the cell lines tested, inclusion of sublethal doses of JQ1 (0.5 μM) significantly improved the efficacy of CDK9 inhibitors on the cancer cells, supporting the contention that either targeting CDK9 alone, or together with BRD4 would potentially be efficacious in combating NSCLC.