After adjusting for grade, human epidermal growth factor receptor‐2 (HER2) and Ki‐67, multivariate Cox regression showed that compared to IDC, NEC had a worse DFS (HR = 2.94, 95% CI: 1.69–5.12, p < 0.001) (Figure 1A). Here, ERBB2 is linked to neuroendocrine carcinoma.