An European research network grouping surgeons, pathologists, biochemists and molecular biologists is presented. The aim of this network is to define new diagnostic, prognostic and therapeutic markers at protein and RNA levels in colorectal cancer. The methodology is based on specific sample preparation techniques, allowing the isolation of pure epithelial cells, and on differential-display techniques, such as two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and reverse arbitrarily-primed polymerase chain reaction (RAP-PCR).