ERBB2 and neoplasm: In a similar manner to the data for the primary tumours, mALN-to-contralateral ratios were higher in HER2-positive mALNs (34.3 ± 27.6) than in HER2-negative mALNs (9.2 ± 3.5) (p = 0.0005, Mann–Whitney test) (Figure 5, Supplementary Table S3).