As the squamous regions of mixed histology tumors had both upregulation of PD-L1 and downregulation of FOXA1 expression, we hypothesized that urothelial to squamous lineage plasticity and immune heterogeneity were coordinately dysregulated in mixed histology bladder cancers through changes in FOXA1 gene expression. The gene discussed is FOXA1; the disease is urinary bladder carcinoma.