Metallothionein immunoreactivity in head and neck carcinomas; special reference to clinical behaviors and chemotherapy responses.

Metallothionein (MT), has selectively binding affinity for heavy metal ions and over expression of MT has a potential against resistance for CDDP anticancer agents and radiation treatment. The role of MT immunoreactivity of squamous cell carcinoma in oral and pharyngeal regions (n = 28) and in the maxillary sinus region (n = 3) was evaluated for distribution patterns of MT and clinicopathologic behaviors. All the sections were examined in 400x and counted for MT positive cells over 5 fields of tumor growing foci. MT immunoreactivity was expressed in both tumor cell cytoplasm and nuclei, and showed heterogeneous localization in tumor epithelial cells and in the stroma. Immunohistochemical localizations showed mosaic patterns as the highest MT staining tumor cells intermingled with negative or low staining cells in neoplastic foci, and in stromal cells. Histiocytic and fibrocytic cells in both peripheral and interstitial stromas were also not stained homogeneously. In oral and pharyngeal carcinomas (n = 28), MT positive cell index in treated cases (n = 11) was 17.85% and that in non treated tumors (n = 17) was 25.19%. In maxillary sinus carcinomas (n = 3), MT positive index was 4.56% and showed lowers levels as compacted to other SCC sites. Among histological grading in oral and pharyngeal SCCs, MT index of well differentiated SCC (n = 9) was 17.04%, of moderately differentiated SCC (n = 13) 21.92% and poorly differentiated SCC (n = 6) was 31.06%. There is no significant correlation of positive index of metallothionein between treated and untreated samples taken in oral and pharyngeal SCCs.