Immunohistochemical localization of glycosaminoglycans with the use of monoclonal antibodies in salivary pleomorphic adenomas.

Immunohistochemical identification of glycosaminoglycans (GG) in salivary pleomorphic adenomas (63 cases) was made to evaluate chondrogenesis in modified myoepithelial cell regions. Monoclonal antibodies (MoAbs) to GGs were used in conjunction with specific enzyme digestion, and chondroitin 4S proteoglycan (C4SPG), chondroitin 6S PG(C6SPG), dermatan sulfate PG(DSPG), heparan sulfate PG(HSPG) and keratan sulfate PG(KSPC) were identified. Modified myoepithelial cells showing fibrillar and plasmatoid shapes contained KSPG (68%), DSPG (32%) and CSPG(C6SPG:22%, C4SPG:33%). Foci of chondroidally changed cells stained intensely for KSPG (53%), and less so for CSPG(C6SPG:22%, C4SPG:33%), and DSPG (19%). Perinuclear matrix in chondroidal tissue reacted most strongly. Almost all types of modified myoepithelial cells, or outer layer tumor cells of tubulo-ductal structures, produced or synthesized CSPG, DSPG, and HSPG. Certain cells located in hyalinous and myxomatous tissues may undergo chondroidal metaplasia, and clusters of such cells may produce GGs and PGs in the perinuclear zone similar to those GGs in matrix synthesized in chondroidal tissue. GG-synthesizing cells might continuously produce KSPG until the cartilage matrix is completed.