MMP9 and laryngeal carcinoma: MMP‐2 and MMP‐9 gelatinases promote invasion and migration by degrading collagen and fibronectin matrices.39 Thus, the expression levels of matrix metalloproteinases (MMPs), including MMP‐9 and MMP‐2, are used as a hallmark for tumour migration and invasion.22 Through experimental analysis, it is concluded that low concentration of DHL can inhibit the migration of laryngeal carcinoma cells.