Abstract
The authors wish to retract their research article entitled 'Serum‑free‑medium‑type mesenchymal stem cell culture supernatant exerts a protective effect on A549 lung epithelial cells in acute lung injury induced by H2O2', published in Oncology Reports 40, 3033‑3039, 2018. After the publication of this article, the authors have become concerned that there were flaws in their study design that have called into question the reported results. On repeating certain of the experiments, the authors found that the Nrf2‑Keap1‑ARE signaling pathway only has a role in the lung epithelial cell injury model, whereas it does not serve a role in the A549 model. Further studies are required to validate the role of the Nrf2‑Keap1‑ARE signaling pathway and the apoptosis‑associated proteins. In particular, the results presented in Fig. 5, showing the difference between Bax and Bcl‑2, appear to be incorrect. For these reasons, the authors have decided to retract the article from the publication. All the named authors on the paper agree to this retraction. The authors sincerely apologize for any inconvenience that might result from the retraction of this article. [the original article was published in the Oncology Reports 40: 3033‑3039, 2018; DOI: 10.3892/or.2018.6656].