One of the genes on this list, creatine kinase-brain (CKB), was identified by us in a prior study using established CRC cell lines and shown to act extracellularly to generate phosphocreatine, which is subsequently transported into the cell as a metabolic energetic source for ATP generation in the hypoxic microenvironment of the liver (Loo et al., 2015). This evidence concerns the gene CKB and colorectal carcinoma.