A method of treating B-cell malignant cancers or T-cell malignant cancers by administering to a patient a pharmaceutically acceptable amount of a composition comprising (S)-2-[4-(4-chlorophenyl)-2,3,9-trimethyl-6H-thieno[3,2-fJ [l,2,4]triazolo-[4,3-a][l,4]diazepin-6-yl]-N-(4- hydroxyphenyl)acetamide. The B-cell malignant cancers include diffuse large B-cell lymphoma and splenic marginal zone lymphoma. The T-cell malignant cancers include anaplastic large T-cell lymphoma.