DEMONSTRATION OF NUCLEOLAR ORGANIZER REGIONS IN LUNG-CARCINOMA BY SILVER STAINING

Nucleolar organizer regions (NORs) were investigated in lung carcinoma s by silver staining. This method was applied to Ill lung carcinoma sp ecimens, including 40 with squamous cell carcinoma (SCC), 42 with aden ocarcinoma (ADENO), 8 with adenosquamous carcinoma (ADESQ), 8 with sma ll cell carcinoma (SMCC), 6 with large cell carcinoma (LGCC), and 7 wi th typical carcinoid tumors (CAOID). The mean AgNOR counts of ADENO, S CC, ADESQ, SMCC, and LGCC were significantly higher than those of the normal bronchial surface and those of the glandular or alveolar epithe lium. The mean AgNOR count of CAOID was significantly higher than thos e of the normal glandular and alveolar epithelium but not that of the surface epithelium. The mean AgNOR count of SCC was significantly high er than that of bronchial squamous metaplasia, and the count of SMCC w as significantly higher than that of CAOID. Within the same cancer cat egory, the mean number of AgNORs increased in parallel with the histol ogical tumor grades. These results indicate that the AgNOR method is u seful for differentiating lung carcinoma from its normal counterparts and for evaluating histological tumor grades in the same lineage of lu ng carcinoma.