RETRACTION: Z. Chen, Y. Chai, T. Zhao, P. Li, L. Zhao, F. He, Y. Lang, J. Qin, H. Ju, "Effect of PLK1 Inhibition on Cisplatin-resistant Gastric Cancer Cells," Journal of Cellular Physiology 234, no. 5 (2019): 5904-5914, . The above article, published online on 29 November 2018 in Wiley Online Library (), has been retracted by agreement between the authors; the journal Editor-in-Chief, Alexander Hutchison; and Wiley Periodicals LLC. The retraction has been agreed upon the authors' request. After the publication of their article, the authors discovered that the cell lines BGC-823 and SGC-7901 used in their study have been reported as contaminated [1, 2]. The authors have contacted the journal requesting the retraction of their article as these issues compromise the reliability of the research presented. The retraction is warranted, as the editors concur with the authors that the data is unreliable and the conclusions are invalid. REFERENCES [1] F. Ye, C. Chen, J. Qin, J. Liu, C. Zheng, "Genetic Profiling Reveals an Alarming Rate of Cross-contamination among Human Cell Lines Used in China," The FASEB Journal 29, no. 10 (2015): 4268-4272, [2] X. Bian, Z. Yang, H. Feng, H. Sun, Y. Liu, "A Combination of Species Identification and STR Profiling Identifies Cross-contaminated Cells from 482 Human Tumor Cell Lines," Scientific Reports 7, no. 1 (2017): 9774,
