Expression of concern for 'Long non-coding RNA CRNDE promote the progression of tongue squamous cell carcinoma through regulating the PI3K/AKT/mTOR signaling pathway' by Zhongheng Yang <i>et al.</i>, <i>RSC Adv.</i>, 2019, <b>9</b>, 21381-21390. This evidence concerns the gene MTOR and tongue squamous cell carcinoma.