ERBB2 and sarcomatoid carcinoma: Behzatoglu et al. reported the presence of HER2 overexpression in 56% of micropapillary carcinomas (MPCs) and only 36% of conventional BCs; on the other hand, HER2 positivity rates declined to 20% in the group of BCs with squamous differentiation (SD-BC), and no expression was seen in the cases of sarcomatoid carcinoma (SCs) and BC with glandular differentiation (GD-BC) [67], in keeping with the findings by Wang et al. on a cohort of upper urinary tract UCs [68].