Relationship between in vitro chemosensitivity assessed with MTT assay and clinical outcomes in 103 patients with acute leukemia.

Abstract

BACKGROUND: Cellular drug resistance is supposed to play a major role in chemotherapy failure or relapse. The purpose of this study was to analyze the relationship between in vitro chemosensitivity test results using a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and clinical response on chemotherapy, and to find the possibility of optimizing the treatment protocol for individual patients according to their actual drug resistance. METHODS: For MTT assay, we obtained bone marrow aspirates from 103 patients with acute leukemia at the time of initial diagnosis or relapse. The following drugs were tested: cytarabine, vincristine, methotrexate, daunorubicin, dexamethasone, L-asparaginase, and mitoxantrone. To evaluate clinical responses after induction chemotherapy, we followed up on their bone marrow study. RESULTS: In our study, in vitro chemosensitivity test with the MTT assay significantly predicted whether patients with AML remained continuous complete remission or went into relapse. It also predicted whether or not child patients with ALL would acquire complete remission after induction chemotherapy. CONCLUSIONS: Although it does not provide the insight into the mechanisms that cause drug resistance, the MTT assay may be a useful tool in individually optimizing the chemotherapy of patients with acute leukemia.