Two of these tumors (cases 2 and 12) showed remarkable heterogeneity in HER2 expression/amplification by IHC/SISH with clearly amplified tumor areas, but not reaching cut-off levels in ddPCR investigating the whole tumor (case 2 in Fig. 3m, n and case 12 in Fig. 3a, b). This evidence concerns the gene ERBB2 and neoplasm.