ERBB2 and neoplasm: Two of the three HER2-amplified cytological samples (one retroperitoneal lymph node and one liver metastasis) showed a HER2 cluster pattern in the whole-tumour cell population, whereas the third sample, a sovraclavear lymph node metastasis, had an average gene copy number of 12 and a HER2/CEP17 FISH ratio of 4.0 in 90% of tumour cells.