The earlier studies on the prognostic significance of blood Hb levels in CRC have been controversial, with reports of the association of anemia with lower survival in advanced colorectal cancer9, lower OS in stage II-III CRC treated with FOLFOX chemotherapy10, lower OS in stage I-III CRC13, no independent prognostic value in stage I-III CRC14, adverse OS in metastasized CRC15,19, poor OS in stage I-III rectal cancer, and no prognostic value in unselected colon cancer material20. Here, GSTM1 is linked to anemia (phenotype).