This is the first report to demonstrate that the antitumor activity of the CDK7 inhibitor BS-181 is exerted by G1-cell cycle arrest and TRAIL/DR5 upregulation-mediated initiation of the extrinsic pathway, and subsequent activation of the intrinsic mitochondria-dependent pathway of apoptosis, which was preferentially provoked in G1 phase, in human T-ALL Jurkat T cells. The gene discussed is TNFRSF10B; the disease is acute lymphoblastic leukemia.