Abstract: The invention provides therapy for treating cancers, such as Bcl-2+ cancers, and Bcl-XL? cancers, and other neoplasms, using romidepsin. The invention provides, inter alia, methods of treating lymphomas, e.g., lymphomas characterized by one or more of Bcl-2 expression, lack of overexpression of Bcl-XL, lack of overexpression of P-glycoprotein, with romidepsin. In some embodiments, the lymphoma is a cutaneous T cell lymphoma. In some embodiments, the lymphoma is a peripheral T cell lymphoma. Romidepsin can be administered a dosages ranging from 0.5 mg/m2 to approximately 28 mg/m2 (e.g., from 1 mg/m2 to 15 mg/m2, from 4 mg/m2 to 15 mg/m2, from 8 mg/m2 to 14 mg/m2, or from 4 mg/m2 to approximately 10 mg/m2). Romidepsin can be administered with a second agent, such as a cytotoxic agent, a steroidal agent, a proteasome inhibitor, or a kinase inhibitor.