Evaluation of the biological malignancy in hepatocellular carcinoma by argyrophilic nucleolar organizer region (AgNOR) staining—Morphological study of AgNOR using image analyzer—

Abstract

Using the Colloid silver staining technique to reveal AgNOR and immunostaining for anti-PCNA monoclonal antibody, 23 resected specimens with hepatocellular carcinoma (HCC, ≤3.5cm in diameter) were examined. These cases were divided into two groups ; Group A [9 cases without vascular invasion and a satellite nodule] and Group B [14 cases with satellite nodules]. Comparison of AgNOR score, the morphological features of AgNOR (the area and roundness factor of AgNOR) and PCNA labeling index between Group A and Group B was made by a image analyzer (SP-500). The AgNOR scores and PCNA labeling indices of HCCs in Group B were significantly higher than those of HCCs in Group A. And a close correlation was shown between AgNOR score and PCNA labeling index. Further more, the area, form, and distribution of AgNORs within the nucleus were also different in the two study groups. In Group A, many AgNORs were regular and medium-sized brown dots (AgNOR-roundness factor ; ≥80%, AgNOR-area ; 1.5 ?? 4.5μm²). But in Group B, AgNORs showed marked variation in size and form. These results suggest that HCCs with multiple, smaller, irregular, and widely dispersed AgNOR in combination with high AgNOR scores have a more aggressive potential. The morphological features of AgNOR may be useful indicators for evaluating the proliferative activity of HCC.