DSG1 and paraneoplastic pemphigus: As envoplakin, periplakin, and desmoplakins (but not Dsg1 and Dsg3) are highly expressed in bladder tissue, and owing to the high specificity of this substrate (74% sensitivity, 99–100% specificity), positive IgG reactivity with the urothelium is considered a diagnostic indication of paraneoplastic pemphigus (38, 139) (Figure 2E).