Interestingly, treatment with THZ531, an inhibitor of both CDK12 and CDK13, has been shown to elicit a synthetic lethal response in Ewing Sarcoma cells expressing the EWS/FLI oncogene36, lending credence to the potential for certain genetic aberrations to dictate CDK12 essentiality. The gene discussed is CDK12; the disease is Ewing sarcoma.