Fibronectin expression in salivary gland pleomorphic adenoma

The distribution of fibronectin in the normal and pleomorphic adenoma of the salivary gland was investigated in forty cases of surgically resected tumor specimens. The immunoreactivity of fibronectin using polyclonal antibody (anti-fibronectin A2 45, Dakopatts, Denmark) was detected in the cytoplasm of intercalated duct cells and certain striated duct cells in normal salivary glands. Pleomorphic adenoma showed few fibronectin positive cells with a scattered or isolated distribution within the epithelial tumor elements of tubulo-ductal or solid foci of tumor cells. Modified myoepithelial cells and luminal cells of tubulo-ductal structures reacted strongly to fibronectin. In hyalinous, myxoid and chondroid areas, fibrillary myoepithelial cells expressed strongly positive reactivity but with diffuse staining in the myxoid and chondroid areas suggesting that fibronectin plays an important role in tumor cell-extracellular matrix interactions to produce the complex histopathological features of pleomorphic adenoma.