The study is the first to attempt a categorization of gastric cancers into HER2 amplification-negative, -equivocal, and -positive cases by using a two-dimensional scatter plot or TC chart, based on measured values of HER2/CEP17 ratio obtained by digital PCR [r] and TCR [x] without conventional HER2-DISH or HER2-IHC information. The gene discussed is ERBB2; the disease is gastric cancer.