APOBEC3A and neoplasm: To better understand if a specific cell type was responsible for APOBEC3A expression, we examined scRNAseq data from five previously unpublished UC tumors from our own institution (n = 4 pure UC, n = 1 UC with 5% squamous differentiation) as well as scRNAseq from a single tumor from Warrick et al. derived from a urothelial tumor with extensive squamous differentiation5.