ERBB2 and neoplasm: The heterogeneity of HER2 gene status in neoplastic tissues obtained from different sites in the same patient is confirmed by our findings in synchronous LNMs, with a number of patients showing a difference in HER2 gene status between the primary tumor and its distant metastasis: in 4 cases (3.9%) the HER2 gene status was observed to be positive in the PGCs and negative in the LNMs, while in 6 cases (5.9%), HER2 gene status was positive in the LNMs and negative in the PGCs.