A total of 40 out of the 50 HER2-positive tumor samples was sequenced using Ion Ampliseq Cancer Panel to identify hotspot mutation in 50 oncogenes or tumor suppressor genes: TP53 (54%), CDKN2A (4%), KRAS (2%), KIT (2%), and PIK3CA (2%) (Figure 1C). This evidence concerns the gene CDKN2A and neoplasm.