Expression of Concern

The Publisher and Editor are issuing an Expression of Concern on the article titled “Butyrate Increases Apoptosis Induced by Different Antineoplastic Drugs in Monocytic Leukemia Cells” [Chemotherapy. 2004; 50(5):221–228. https://doi.org/10.1159/000081942] by M.G. Ramos, F.L.A. Rabelo, G. Brumatti, A.E. Bueno-da-Silva, G.P. Amarante-Mendes, and J.I. Alvarez-Leite.After the publication of this article, concerns were raised about the unexplained duplication in Figure 5 between the Actin for the ETOP treatment and the Actin for the Vinc+But treatment and between the Actin for the Vinc treatment and the Actin for the BUT treatment.When asked to comment on this, the authors stated that due to the time that has passed since the publication of our article, they are unable to locate the original Western Blot files.As the matter cannot be conclusively resolved, this Expression of Concern is being issued to make readers aware of the image reuse within Figure 5. Appropriate editorial action will be taken should additional information become available.