ABSTRACT
BACKGROUND: The MACIS score uses metastasis, age, completeness of resection, local invasion, and tumor size to stratify patients with papillary thyroid carcinoma (PTC) into four groups with different survival. METHODS: Immunostaining for proliferating cell nuclear antigen (PCNA) was done in 43 cases of PTC. Relationships between proliferative index (percentage of cells that were PCNA positive) and the MACIS parameters were examined. Double staining for PCNA and for silver-stained nucleolar organizer regions (AgNORs, indicating proliferation) was performed in 10 cases. RESULTS: PCNA was detected only in tumor cells. The proliferative index was low (mean, 14.2%; median, 13.0%), did not differ between MACIS groups (p = 0.56), and showed no association with individual MACIS parameters. PCNA immunostaining correlated with AgNOR staining. The mean AgNOR count was 2.28 in PCNA-positive cells and 1.85 in PCNA-negative cells (p