CENTRAL GIANT-CELL GRANULOMAS OF THE JAWS - PHENOTYPE AND PROLIFERATION-ASSOCIATED MARKERS

Central giant cell granulomas (CGCGs) are jaw tumors of unknown origin that often exhibit an aggressive, though unpredictable, clinical cour se. The purpose of this study was to determine the immunoprofile of th e mononuclear cells that seem to be responsible for the biologic behav ior of these tumors. Numbers of cells in cell cycle were also determin ed and compared in clinically aggressive and nonaggressive CGCGs. Sixt een aggressive and 12 non-aggressive CGCGs were immunohistochemically stained with antibodies to CD34, CD68, factor XIIIa, alpha-smooth musc le actin, prolyl 4-hydroxylase, Ki-67, and p53 protein. Cell populatio ns and numbers of cells in cell cycle were determined through microsco pic quantitative assessment. CD34-positive cells were limited to suppo rt vessels. CD68-positive mononuclear cells constituted a small popula tion of cells in all tumors. With two exceptions, factor XIIIa-positiv e cells were rarely seen. Alpha-smooth muscle actin staining was prese nt in approximately half the tumors, and occasionally large numbers of positive cells were seen. Most mononuclear cells were positive for fi broblast-associated antigen. No phenotypic differences were detected b etween aggressive and non-aggressive tumors. P53 protein did not appea r to be overexpressed in CGCGs. Ki-67 staining showed that only mononu clear cells were in cell cycle, and that there were no differences bet ween aggressive and non-aggressive tumors. We conclude that CGCGs are primarily fibroblastic (and myofibroblastic) tumors in which macrophag es appear to play a secondary role. Tumor cells show no differentiatio n toward endothelial cells or macrophage-related dendrocytes (factor X IIIa). Cellular phenotypes and numbers of cells in cell cycle are simi lar in both aggressive and non-aggressive tumors.