ERBB2 and neoplasm: Univariable analysis (Table 3) showed that characteristics associated with PE were age (P = 0.001), T stage (P < 0.001), N stage (P = 0.01), histologic grade (P < 0.001), HR status (P = 0.03), HER2 status (P = 0.03), Ki-67 index (P < 0.001), subtype (P < 0.001), lymphovascular invasion (P < 0.001), vessel ectasia (P < 0.001), stromal fibrosis (P = 0.004), growth pattern (P = 0.001), and tumor necrosis (P < 0.001).