MODE OF TUMOR INVASION IN ORAL SQUAMOUS-CELL CARCINOMA - IMPROVED GRADING BASED ON IMMUNOHISTOCHEMICAL EXAMINATION OF EXTRACELLULAR MATRICES

Background. To predict the nodal involvement of oral squamous cell car cinoma (OSCC) many investigators have studied the histologic features of primary tumors. However, conventional histologic grading still is n ot sufficient to provide an objective and practical evaluation. In thi s study we tried to modify one standard type of histologic grading, na mely, mode of invasion (MI), on the basis of the extracellular matrix (ECM) staining pattern. Methods. One hundred seventeen initial biopsie s of primary OSCC were histologically examined, and the MI was graded. The expression of a series of ECMs-laminin, type IV collagen, heparin -sulphate proteoglycan, fibronectin, tenascin, decorin, and vitronecti n-was immunohistochemically examined. Results. The ECM staining patter n showed a close association with the MI, and was classified into type s I and II. The type I staining pattern was observed in the noninvasiv e cases (MI grades 1 and 2), while type II was in the highly invasive cases (MI grades 4c and 4d). Because the ECM staining pattern in the m oderately invasive cases (Ml grade 3) included both types I and II, th ese cases were subdivided and compared. As a result, the type II cases showed a significantly higher incidence of nodal involvement than did the type I cases. Conclusion. An examination of a series of the ECMs, in addition to the conventional histologic examination, is thus consi dered to provide more objective and practical data to evaluate the inv asive and metastatic potential of OSCC. (C) 1996 John Wiley & Sons, In c.