Expression of Collagen IV a1 to a6 Chains in Basement Membranes of Odontogenic Tumors

Type IV collagen, the major component of basement membrane (BM), demonstrates a stage- and position-specific distribution of its isoforms during tooth development. To determine its localization in BM of odontogenic neoplasms, immunohistochemistry using six anti- a (IV) chain-specific monoclonal antibodies was performed. Expression of a 1(IV)/ a 2(IV) and a 5(IV)/ a 6(IV) chains was stronger in the desmoplastic than in ordinary ameloblastomas. The adenomatoid odontogenic tumor distinctly expressed these chains in BM of cribriform areas and hyaline materials (which was also a 4(IV)-positive. These five chains also stained BM and tumor cells of ameloblastic fibroma. Present results suggest that collagen IV composition and distribution in the basement membranes of odontogenic neoplasms plays a key role in tumor growth and progression.