MMP14 and cancer: Emerging evidences indicate that Snail confers tumor cells with cancer stem cell-like traits, and promotes tumor recurrence and metastasis.28 To confirm whether downregulation of MMP14 and Snail by miR-22 could result in inhibition of migration and invasion of GC cells, we knocked down the expression of endogenous MMP14 or Snail by their small interfering RNAs (siRNAs) to mimic the effects of miR-22 overexpression.