GSTM1 and anemia: The main findings of this study are: (i) the minimum postoperative Hb levels and Hb drop were similar between laparoscopic and open group; (ii) no differences were observed in terms of rate and number of postoperative RBC transfusions between the laparoscopic and the open group; (iii) the need for postoperative RBCs were mainly related to the presence of preoperative anaemia and occurrence of postoperative complications; (iv) up to 15% of patients undergoing elective, curative resection, for non-metastatic colorectal tumour were transfused postoperatively with at least one unit of RBCs.