When it comes to overall survival, 5-year OS rate of stage T1 with preoperative serum CEA elevation (48.3%) was even lower than stage T3 involved in CEA elevation (54.5%) and did not achieve statistical difference from stage T4 (45.3%), meaning elevated preoperative serum level of CEA could identify a subgroup of stage T1 rectal cancers with similar CSS compared with some stage T3 diseases and with similar OS compared with some stage T4 diseases. The gene discussed is CEACAM5; the disease is rectal cancer.