In order to avoid introducing bias into the results, considering that the sample size of signet ring cell carcinoma is relatively small (n = 11) and all the HER2 expressions are negative, we conducted a multivariate analysis only on the patient samples of the gastric adenocarcinoma type and carried out cross-validation to assess the predictive efficacy. The gene discussed is ERBB2; the disease is gastric adenocarcinoma.