Colorectal cancer is the fourth most common cause of cancer deaths worldwide and the high mortality rate is mostly ascribed to liver metastasis.Unfortunately,with the exception of carcinoembryonic antigen (CEA),there are no other clinically useful serological biomarkers available for prognosis.The secretome,consisting of all the proteins secreted by cells into the extracellular environment,is a highly promising source for identifying serological biomarkers of cancer metastasis1.Here,we present two approaches in mining the colorectal cancer secretome for novel prognostic biomarkers.