SMARCB1 and nasal cavity and paranasal sinus carcinoma: Studies on the molecular underpinnings of SMARCB1 protein loss, using a variety of testing tools such as fluorescence in situ hybridization (FISH) and next-generation sequencing, have demonstrated homozygous (biallelic) or heterozygous (monoallelic) deletions of the SMARCB1 gene in SMARCB1-deficient sinonasal carcinomas [12, 17, 20, 21].