ERBB2 and neoplasm: Previous morpho-immunohistologic studies [15–19] have shown that a subgroup of HER2+ tumors consistently demonstrate several features classically ascribed to basal-like tumors, including poor differentiation, high-grade, geographic necrosis, pushing margins of invasion, syncytial arrangement of tumor cells, ribbon- or festoon-like, squamous metaplasia, stromal lymphocytic infiltrates, high mitotic index, and p53 positivity.