Our study suggests that positive IDH2 11C8B1 immunohistochemistry in sinonasal carcinomas would be highly predictive of the presence of IDH2R172S/T mutations and could serve as a reliable adjunct diagnostic marker of sinonasal undifferentiated carcinomas in >70% cases.
We demonstrate that the majority of histologically defined sinonasal undifferentiated carcinomas are characterized by IDH2R172X mutations and overexpression of mutant protein.