FGFR3 and carcinoma: Our results highlight significant heterogeneity of these tumors but point to the existence of three groups of FGFR3::TACC3-fused head and neck carcinomas: (1) unclassified carcinomas sharing distinctive morphological features in favor of a novel tumor type driven by the fusion, (2) HPV-associated (mostly sinonasal) carcinomas with concurrent FGFR3::TACC3 fusions, and (3) conventional SCC where the fusion probably represents a random event.