Detection of nucleoproteins in squamous cell carcinoma, and dysplastic and normal mucosa in the oral cavity by methyl green-pyronin staining.

Squamous cell carcinoma (SCC) is the most malignant neoplasm of the oral cavity. The mortality rate associated with head and neck cancers remains high, and thus detection techniques are important. In the present study, methyl green-pyronin staining was applied to 5 normal mucosa specimens, 10 cases of dysplastic mucosa, 12 cases of SCC (grade I), 10 cases of SCC (grade II) and 5 cases of SCC (grade III) in the oral cavity. This is the first study in which nuclear and nucleolar cytomorphometric parameters (diameter, area and number) in such oral lesions were evaluated using this method. As methyl green-pyronin selectively stains nucleic acids, it can differentiate between DNA (green) and RNA (red). The results reveal that the proposed method can be used to evaluate changes in the nucleus and nucleolus in premalignant lesions in the oral cavity.