ERBB2 and neoplasm: Interestingly, in Kaplan–Meier survival analysis, at cut-off value ≥5% of tumour cells with staining, only the co-expression of HER2/HER4 was associated with statistically significant prolonged survival (1.08 ± 0.25 vs. 1.94 ± 0.29, p = 0.031).