Methods of treating Mcl-1 dependent cancers are described herein. The methods can include determining whether the cancer is Bfl-1 positive, and administering an inhibitor of CDK9 to a patient if the cancer is Bfl-1 positive.本文描述了治療Mcl-1依賴性癌症之方法。該等方法可以包括確定癌症是否為Bfl-1陽性,以及如果癌症為Bfl-1陽性,則向患者投與CDK9的抑制劑。