Nucleolar organizer regions as a prognostic factor in surgically treated lung cancer patients

The prognostic value of the number of nucleolar organizer regions (NORs) (DNA loops in the nucleus) in tumor cells from various kinds of malignancies has been widely studied in recent years. During the period 1989 to 1992, a total of 73 primary lung tumors was examined for the number of NORs by silver staining AgNOR proteins on the stump smear of resected specimens in this hospital. The relations of the mean number of AgNOR per cell with other factors such as sex, age, habit of smoking, performance status, tumor location, tumor size, pathological stage, histological type, degree of differentiation, and whether histologically vascular or lymphatic invasion were analysed. It was found that the mean number of AgNOR was significantly different between positives and negatives of histologically vascular or lymphatic invasion (6.4 +/- 0.4 vs 5.5 +/- 0.2) (p < 0.05). Both single and multiple-variate analysis of patient survival revealed that the mean number of AgNOR was a significant prognostic factor, as were pathological stage, histological type, and performance status of the patient. Patients with a higher mean number of AgNOR (> 7) had a significantly worse prognosis compared with those with less AgNOR (< or = 7) (median survival 28 versus 43 months) (p < 0.05). It was concluded that the mean number of AgNOR of tumor cells is a significant prognostic factor in surgically treated lung cancer patients.