ABSTRACT
BACKGROUND: TACE/ADAM17 is a transmembranous protease that cleaves membrane-bound growth factors like EGFR ligands. TACE-dependent proteolysis is regulated by its inhibitor, tissue inhibitor of metalloproteinases 3 (TIMP3). This study analyses the role of TACE and TIMP3 mRNA expression in squamous cell carcinomas of the head and neck (HNSCCs). METHODS: We analysed TACE and TIMP3 mRNA expression in HNSCCs from 106 patients by RNA in situ hybridisation. RESULTS: TACE mRNA was upregulated in HNSCCs compared with dysplastic (P<0.05) and normal epithelia (P<0.001), with strong hybridisation signals in 21.9% of invasive tumour tissues and 4.5% of dysplasia. Elevated mRNA levels were accompanied by increased amounts of TACE protein in HNSCCs. TIMP3 mRNA expression in HNSCC-associated stroma was significantly higher than in the stroma adjacent to dysplastic or normal epithelia. Expression of TACE mRNA in HNSCCs was associated with tumour stage (P=0.019) and regional lymph node metastasis (P=0.009). Furthermore, levels of TACE mRNA in HNSCCs correlated with the expression of TIMP3 mRNA in HNSCC-associated stroma. Concomitantly, patients expressing high levels of TACE and TIMP3 mRNA showed significantly reduced overall survival compared with those with low mRNA levels. CONCLUSION: Our results indicate an important role of TACE and TIMP3 during development and progression of HNSCCs.
