To address these issues, we undertook an analysis of HER2 in bladder cancer in patients who developed metastatic disease, by evaluating immunohistochemical (IHC) staining for HER2, FISH for ERBB2 on two cohorts of patients, targeted ERBB2 mutation hotspot sequencing, mRNA expression by NanoString, and ERBB2 copy number by array-based comparative genomic hybridization (aCHG) in primary tumors from one of these cohorts. The gene discussed is ERBB2; the disease is urinary bladder cancer.