Gallbladder carcinoma: a video image analysis of AgNOR distribution and its relation to tumour stage and grade

The amount and distribution of interphase argyrophilic nucleolar organizer regions (AgNORs) was studied in 51 gallbladder surgical specimens including 32 primary carcinomas, 10 adenomas and 9 cases of chronic cholecystitis with calculi. The mean nuclear AgNOR area (NORA) and the AgNOR distribution score (NORDS), i.e. the percentage of cells carrying nucleolar aggregates with more than 6 distinct silver dots, were evaluated in 200 epithelial nuclei per specimen by means of automated image analysis and direct counting respectively. Statistical analysis (variance analysis and Student-Neuman-Keuls' test) performed on the pooled mean AgNOR values showed a significant difference (p < 0.001) between carcinomas and non-carcinomatous lesions. Both NORA and NORDS highly discriminated carcinomas with histopathological grade 4 versus cases with grade 1, 2 or 3 (p < 0.001); a less statistically significative p value (< 0.05) was encountered when NORDS values of well differentiated grade 1 carcinomas and adenomas were compared. The NORA parameter permitted the discrimination of stage IV versus stage I carcinomas (p < 0.001), while carcinomas in stage IV and those in stage II were distinguished with a p < 0.05; the NORDS parameter allowed also to distinguish stage IV from both stage I or II tumours (p < 0.001). Our results indicate that the above-mentioned AgNOR parameters may be utilized as additional, more objective quantitative criteria in the clinical-pathological assessment of the outcome of gallbladder carcinomas.