Immunohistochemical expression of STAT3 and CD163 tumor associated macrophages in glioma and their correlation with IDH-1

Abstract In the recent World Health Organization (WHO) classification, the isocitrate dehydrogenase (IDH) mutation determines the grade of gliomas. IDH mutation might be associated with cell signaling and the tumor microenvironment. The current study aimed to investigate the association between IDH1 protein immunohistochemical expression and the immunohistochemical expression of Signal transducer and activation of transcription 3 (STAT3) and CD163, the scavenger receptor of monocytes/macrophages. Forty four cases of gliomas are immunohistochemically stained for IDH1 R132H, STAT3, and CD163 antibodies. The results indicated a significant association between STAT3 and CD163 expression with IDH1 R132H expression and glioma grading. High expression of STAT3 and CD163 was found to be significantly associated with IDH1 R132H-negative and high-grade gliomas ( p = 0.001 and 0.01, respectively). Furthermore, a significant positive correlation was found between STAT3 and CD163 expression ( p = 0.000, r = 0.827). In conclusion, IDH1 R132H-negative gliomas might have a phenotype related to activation of the STAT3 signaling pathway and might have specific tumor microenvironment related to tumor immune evasion.