Immunohistochemical expression of stem cell markers OCT-4 and SOX-2 in giant cell tumor, central giant cell granuloma, and peripheral giant cell granuloma

Objectives This study aimed to evaluate and compare the immunohistochemical expression of OCT-4 and SOX-2 and to determine their use in differentiating giant cell tumor (GCT) from central giant cell granuloma (CGCG) and peripheral giant cell granuloma (PGCG). Study Design Formalin-fixed, paraffin-embedded tissue blocks of 10 histopathologically diagnosed cases of GCT, CGCG, or PGCG were examined for anti–OCT-4 and anti–SOX-2 antibodies. Nuclear staining of stromal mononuclear cells and multinucleated giant cells was considered positive for OCT-4 and SOX-2 expression. Results Nuclear immunoexpression of OCT-4 in stromal mononuclear cells was observed in 80% (8 of 10) of GCT cases, whereas none of the CGCG and PGCG cases showed OCT-4 immunoreactivity. SOX-2 immunoreactivity was negative in GCT, CGCG, and PGCG. Conclusions OCT-4 immunopositivity in GCT can be used as a cancer stem cell marker to differentiate GCT from CGCG and PGCG. The presence of OCT-4 in GCT versus its complete absence in CGCG and PGCG suggests that these three conditions are separate entities. The absence of stem cell marker OCT-4 and SOX-2 raises questions regarding their role in the pathogenesis of CGCG and PGCG.