Somatostatin receptor 2a is a more sensitive diagnostic marker of meningioma than epithelial membrane antigen

Excerpt

Meningioma is the most common extraaxial primary central nervous system tumor. While most are diagnosed on routine hematoxylin- and eosin-stained sections, the morphologic spectrum is wide and immunohistochemistry (IHC) is occasionally necessary for diagnosis. Currently, the most reliable IHC markers for meningioma are epithelial membrane antigen (EMA) and progesterone receptor (PR), though both have suboptimal sensitivities and specificities [4, 7]. Previous studies suggest that meningiomas express somatostatin receptors, especially somatostatin receptor 2a (SSTR2a) [1, 5, 6, 8], and one prior study found that a polyclonal SSTR2a antibody stained 87 % of WHO grade I and grade II meningiomas, although EMA stained 97 % of the same cohort [2]. A commercially available monoclonal SSTR2a antibody was recently developed [3]. STAT3 is a potential downstream target of SSTR2a in mouse embryonic stem cells [9]. Therefore, we studied a large meningioma tissue microarray (TMA) with SSTR2a, EMA, PR and phosphorylated STAT3 (pSTAT3) immunohistochemistry. …