Objective This study aims to investigate the post-transcriptional regulatory effects that control proliferation, apoptosis, and invasion in pediatriccholesteatoma keratinocytes.In particular, the potential role of miR-21was focused on in this study.Methods A total of 23 pediatric cholesteatoma tissues were processed for cell culture.Pediatriccholesteatoma keratinocytes were transfected with miR-21 inhibitors, or negative control miRNAs.RT-PCR was used to assess the expression levels of miR-21.EdU incorporation assay and TUNEL staining were used to assess the proliferation and apoptosis of pediatric cholesteatomakeratinocytes, respectively.Results MiRNA-21 was downregulated when pediatric cholesteatoma keratinocytes were transfected with miR-21 inhibitors.Furthermore, the number of proliferative EdU+cells decreased in cholesteatoma keratinocytes transfected with miR-21 inhibitors;and the number of TUNEL-positive cells also increased in cells transfected with miR-21 inhibitors, compared with cells transfected control miRNA.Conclusion MiRNA-21 promotes the proliferation and inhibits apoptosis of pediatric cholesteatoma keratinocytes.