Except for human CXCL9, in which mRNA levels in the lung tumours were not detectable, we observed significantly higher expressions of human CXCL10 (33-fold increase) and CXCL11 (28-fold increase) by the lung CRC metastases, which suggest a possible mechanism for the lung CRC metastases to promote their development. This evidence concerns the gene CXCL9 and medical procedure.