ERBB2 and micropapillary urothelial carcinoma: This seems logical given that aggressive variants like the micropapillary subtype (which is often HER2-positive) have a poor prognosis; in one study of micropapillary urothelial carcinoma (MPUC), patients with ERBB2 amplification had nearly a 3-fold higher risk of death from the disease compared to those without amplification [9].