In all, 9 of the 10 cases showed a cluster amplification in both primary and metastasis; the tumour with heterogeneous HER2 amplification in the primary showed an increase in both HER2 gene copy number (4.5 vs 12.0) and the percentage of amplified cells (33 vs 90%) in the matched metastasis. Here, ERBB2 is linked to neoplasm.