MMP15 was down-regulated in all 14 HNSC tumors, including Buccal Mucosa Squamous Cell Carcinoma, Floor of Mouth Squamous Cell Carcinoma, Gingival Squamous Cell Carcinoma, Glottis Squamous Cell Carcinoma, Hard Palate Squamous Cell Carcinoma, Lip Squamous Cell Carcinoma, Maxillary Sinus Squamous Cell Carcinoma, Oral Cavity Squamous Cell Carcinoma, Oropharyngeal Squamous Cell Carcinoma, Postcricoid Squamous Cell Carcinoma, Soft Palate Squamous Cell Carcinoma, Supraglottic Squamous Cell Carcinoma, Tongue Squamous Cell Carcinoma, Tonsillar Squamous Cell Carcinoma. Here, MMP15 is linked to tonsillar squamous cell carcinoma.