DISTRIBUTION OF TENASCIN IN ORAL PREMALIGNANT LESIONS AND SQUAMOUS-CELL CARCINOMA

The distribution of the extracellular matrix (ECM) protein tenascin (T n) was studied in oral premalignant lesions and squamous cell carcinom a by using the monoclonal antibody (Mab) 143DB7. In normal buccal and palatal mucosa, in ventral tongue, in floor of mouth and in gingiva, i mmunoreaction for Tn was seen to be distributed as a continuous thin, delicate line merely in the basement membrane region. Hyperkeratosis w ithout dysplasia showed a distinct zone of enhanced Tn immunoreactivit y immediately beneath the epithelium. In dysplasias of various degree, enhancement of the stromal Tn content could be observed, being most c onspicuous in carcinoma in situ lesions. In most invasive carcinoma ca ses the Tn immunoreactivity was intense, extending deeply into the und erlying stroma. In such lesions Tn-reaction often covered the total st roma, Notably, the strongest immunoreaction was seen at the advancing edges of the tumor. The triggering factor for stromal Tn enhancement s eems to be of epithelial origin. The enhanced expression of Tn suggest s that Tn plays a role in organizing and remodelling the stroma to sup port active epithelial proliferation and migration. However, it also s eems that inflammation is associated with Tn expressions.