抄録
Early invasive carcinomas (EIC) of the tongue (10 lesions), gingiva (7 lesions), floor of the mouth (5 lesions) and buccal mucosa (one lesion) were clinically and histopathologically investigated. Clinically, these EIC were subdivided into leukoplakic (13 lesions), erythroplakic (6 lesions), and erosive/ulcerative type (4 lesions). Coexistence of ulcer/erosion with leukoplakia and erythroplakia indicated a high risk of malignancy. In a few cases, tumor cell invasion into the underlying layer was observed in two or more parts of HE-stained specimens. Furthermore, special staining for silver coloid (Ag-NORs)-positive nucleolar protein granules and a ras-oncogene product (p53) revealed that the staining intensities of Ag-NORs and p53 protein in tumor cells of the EIC were intermediate between those of normal oral mucous membrane epithelial cells (negative control) and deeply invading carcinoma cells (positive control). Compared to leukoplakic type, tumor cells in the other two types expressed much more p53 protein. These results seem to indicate that some oral mucous membrane carcinomas are sequenced from precancerous lesions, that multicentric cancerization may occur, and that p53 expression is increased along with cancer development. Furthermore, erythroplakic and ulcerative early carcinomas seem to be more active than leukoplakic ones.
