['Apoptosis is an essential form of cell death, the failure of which can lead to cancer development. Cancer including leukemia is usually treated with chemotherapeutic drugs that can be effective, but frequently problems are encountered that impair the success of the treatment. Butyrate is a short-chain fatty acid that can have many effects on different cells, including apoptosis.', 'The effect of a combination treatment with butyrate and antineoplastic agents Ara-C, etoposide and vincristine is evaluate on the leukemic cell line THP-1.', 'We show that butyrate increased apoptosis induced by the three agents as seen by measurement of DNA content, annexin exposure and morphological characteristics. We also demonstrate that the process of apoptosis induced by butyrate and chemotherapeutic drugs involves the participation of caspases and induced activation of caspase-3, -8 and -9.'] Does butyrate increase apoptosis induced by different antineoplastic drugs in monocytic leukemia cells?