In the training cohort, statistically significant differences in age, sex, tumor location, CEA level, and CT-reported T stage were identified between pMMR and dMMR patients (P-value <0.05), while other clinical features (BMI, CA19-9 level, CA125 level, AFP level, and CT-reported N stage) showed no statistically significant differences (P-value >0.05). The gene discussed is CEACAM5; the disease is neoplasm.