Silver-binding argyrophilic nucleolar organizer regions (AgNOR) in gall-bladder cancer: correlations with malignant grading and prognosis.

Silver-binding nucleolar organizer regions (AgNOR) were investigated and compared in 43 cases of gall-bladder cancers and 10 normal gall-bladder samples using an image analyzer. The mean numbers of AgNOR per nucleus (AgNOR number) were 3.28 +/- 1.38 in the gall-bladder cancers and 1.86 +/- 0.20 in the normal gall-bladder cases. The respective mean areas of AgNOR per nucleus (AgNOR area) were 6.96 +/- 3.78 microns2 and 1.89 +/- 0.21 microns2. The differences were statistically significant (P < 0.0001) for both parameters. In addition, increased frequency and enlargement were both apparently correlated with poor prognosis (P < 0.011 and P < 0.046, respectively), with AgNOR number and AgNOR area showing tendencies for increase in cases of histologically high grade malignancy, advanced cancer and regional lymph node involvement. In conclusion, AgNOR number and AgNOR area appear to be useful indicators for the grading of malignancies and for the prediction of gall-bladder cancer prognosis.