Metalloproteinases from the gelatinase family, including matrix metalloproteinase-2 (MMP-2) (gelatinase A, collagenase-4) and matrix metalloproteinase-9 (MMP-9) (gelatinase B, belong to a very important group from the perspective of carcinogenic mechanisms of oropharyngeal and tonsillar squamous cell carcinomas. The gene discussed is MMP9; the disease is tonsillar squamous cell carcinoma.