A novel evaluation system of metastatic potential of oral squamous cell carcinoma according to the histopathological and histochemical grading

We established a new evaluation system for metastatic potential of oral squamous cell carcinoma (SCC), utilizing a combined examination of histopathological grades of the carcinomas based on cell differentiation and invasive mode according to Yamamoto’s criteria, and the cellular expressions of CD44, E-cadherin (E-cad), heparan sulfate glycosaminoglycan (HS-GAG) and Phaseolus vulgaris leukoagglutinin (L-PHA)-binding oligosaccharides on the carcinomas. Histochemical patterns of expression of these markers were classified into positive (++), weakly positive (+), and negative (−). The histopathological grades and the histochemical patterns of the SCC were estimated on a 0–2 point scale, i.e. point 2 for poorly differentiated, mode 4D, CD44⁺⁺, E-cad⁻, HS-GAG⁺⁺, or L-PHA⁺⁺; point 1 for moderately differentiated, mode 4C, CD44⁺, E-cad⁺, HS-GAG⁺, or L-PHA⁺; and point 0 for well differentiated, mode 1, mode 2, mode 3, CD44⁻, E-cad⁺⁺, HS-GAG⁻, or L-PHA⁻. As a result, incidence of metastasis in the cases with a total score of more than 6 (62.8%) was significantly higher than that with a total score of less than 5 (9.3%). This evaluation system will yield useful information concerning the prognosis of patients with oral SCC.