Analysis of heterogeneity after PSM between the sub-cohorts stratified by the HB-CEA score cutoffs showed almost balanced distribution of the patient characteristics, including sex, age, tumor location, differentiation, diameter of lesion, cancer embolism, nerve invasion, pathological TNM stage (pTNM), depth of invasion, and lymph node metastasis, among the 64, 128, and 64 patients (HB-CEA=0, 1, and 2, respectively; p>0.05). The gene discussed is CEACAM5; the disease is cancer.