SMARCB1 is a member of the SWI/SNF chromatin remodeling complex and regulates transcription of several genes involved in cell proliferation. SMARCB1 mutations are rare in urothelial carcinomas and are found in about 2% of cases. SMARCB1 A203T is considered a variant of uncertain significance and has not been well classified in the literature. This variant has been reported a somatic mutation in a case of colon adenocarcinoma however this variant has also been reported a germline finding in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/25553173/). These results should be interpreted in the clinicopathologic context.