Valle NRD, et al. - In view of the finding that several histone deacetylases inhibitors (HDACi) raise levels of intracellular oxidative stress, researchers here examine combinations of two structurally distinct HDACi with the redox active compound adaphostin in acute lymphocytic leukemia (ALL). Based on the findings, researchers conclude that a redox modulatory agent, adaphostin, improves the efficacy of two HDACi, vorinostat or entinostat, but through different mechanisms showing a point of divergence in the mechanisms of synergy between the two distinct HDACi and adaphostin.