Katabi N, et al. – The sensitivity and specificity of PLAG1 immunohistochemistry (IHC) in the differential diagnosis of PA and carcinoma ex pleomorphic adenoma (CA ex–PA), were appraised. Also, this study compared the PLAG1 immunohistochemical results to PLAG1 gene abnormalities as detected by fluorescence in situ hybridization (FISH). In excluding a PA diagnosis, a negative PLAG1 IHC appeared to be helpful. FISH was more sensitive than IHC in detecting PLAG1 abnormalities, in the context of CA ex–PA.