Among these, activating HER2 mutations are identified in 1–3% and 1.4–6.7% of NSCLC patients of European/American and Asian descent, respectively; in-frame insertion mutations occurring in exon 20 represent the most common subtype, seen in approximately 48% of the cases [4,5,6,7]. This evidence concerns the gene ERBB2 and non-small cell lung carcinoma.