Comparison of nucleolar organizer regions (NORs) on chromosomes of cultured lymphocytes from cancer patients, high risk cancer family members and normal subjects

Using the technique of AG-NORs, the number of silver-stained NORs on chromosomes of the peripheral lymphocytes from 10 cancer patients, 10 high risk cancer family members and 10 normal individuals was compared. It was found that the total mean value of AG-NORs was 5.46 +/- 0.00/per cell in cancer patients, 5.62 +/- 0.01/per cell in high risk cancer family members and 7.03 +/- 0.07/per cell in normal subjects. The total mean value of AG-NORs was markedly lower in the first two groups than in the third group (P less than 0.001). It seems to be due to the decrease of the transcribed activity of rRNA gene on chromosomes of the cultured lymphocytes in the first two groups. A probable relation between the carcinogenesis and decrease of NORs is shown. The transcribed activity of rRNA gene gives the expression to AG-NORs numbers with which the relation to carcinogenesis is briefly discussed with a review of the literature.