Immunohistochemical Evaluation of D2-40, Galectin-3, Maspin and MCM7 Expression in Palate Squamous Cell Carcinomas

Squamous cell carcinoma (SCC) is the most frequent cancer in oral cavity and its prognosis has exhibited little improvement in the last decades. Although much less common palate SCCs manifests a higher local aggression invading very quickly the adjacent muscles and jawbones, thus being able frequently to lead to dysfunctions in chewing, swallowing, and speech. To elucidate what underlies such local aggression, we investigated the immunohistochemical expression in palate SCCs of Podoplanin (D2-40), Galectin-3 (Gal-3), mammary serine protease inhibitor (Maspin) and minichromosome maintenance complex component 7 (MCM7), markers that are known to be involved in tumor invasiveness. We found a progressive increase in reactivity for D2-40 and MCM7 from the normal epithelium toward dysplastic epithelium and respectively to SCC, which suggests the intervention of these markers in the early stages of squamous cell carcinogenesis in the palate. The highest D2-40, Gal-3 and MCM7 reactivity was observed in basaloid and in poorly differentiated (G3) palate SCCs, while for Maspin the well-differentiated (G1) palate SCCs were the most reactive. The first three markers mentioned above were most intensely expressed at the invasion front, while the Maspin reactivity was low or absent at this level. Statistically, we found significant stratification on localization, grading, muscle invasion, and survival for all investigated markers, but with very high direct correlations between D2-40, Gal-3, and MCM7 immunoreactive score (IRS) values, while between the Maspin and each of the previous markers there were very high inverse correlations. Overall, all these investigate markers proved to be responsible for the local invasiveness and regional lymph node metastasis, thus allowing a prognostic and therapeutic stratification of patients with palate SCCs.