Leukoplakia is a precancerous lesion in OSCC, and it was found that miR-21 secreted from OSCC cells was correlated with low expression of its target genes, TPM1 and PTEN, and was highly expressed in progressive leukoplakia and OSCC to promote disease progression (Liu et al., 2017). The gene discussed is PTEN; the disease is Oral leukoplakia.