GSTM1 and sigmoid colon cancer: We did not observe any significant differences in age, gender, BMI, history of abdominal surgery, concomitant diseases, preoperative chemotherapy, Hb level, serum Alb level, CA199 level, CEA level, ASA physical status, the distances from rectal or sigmoid colon cancer lesions to the anal verge, tumor differentiation status, tumor size, pT stage, pN stage, and TNM stage between the two groups.