In this context, surface enhanced laser desorption/ionization is a proteomic high-throughput technique that uses chromatographic surfaces that are able to retain proteins depending on their Loganin physicochemical properties, followed by direct analysis via time-of-flight mass spectrometry. A multitude of studies using Protein Chip technology have been carried out to establish the protein profiles of biological fluids, especially serum samples. Because this technique demands only a small amount of sample, it can be used for small biopsies or micro dissected tissues, which produce the homogeneous tissue samples typically used in cancer research. The separation of functional tissue areas can be achieved by laser-based microdissection. When laser microdissection was first introduced as a novel preparation technique in 1998, the challenge was to prove that reliable results could be achieved by selecting defined small amounts of isolated cells from complex tissue sections. Since then numerous applications has been published in different fields and has proven its necessity. Micro dissected tissue Famotidine material free from contaminating and unwanted tissue components is extremely important for the production of clean data for biomarker identification in cancer diagnostics and in determining the clonal heterogeneity of tumors. We have shown in a previous study that the detection of differentially expressed proteins was only possible in pure micro dissected samples. Laser-based microdissection has previously been combined with Protein Chip technology to identify protein markers in several cancer types. The aim of this study was to analyse the protein patterns of liver metastases derived from CRC and detect biologically and diagnostically relevant signals. We wanted to analyze whether it is possible to draw conclusions from the proteome of the MTS on the origin/localization of the primary tumor. Negative controls were incubated with only the labelled secondary antibody. Sections cut in parallel to the immunohistochemically treated sections were stained with haematoxylin�Ceosin for better identification of the different tissue areas. Immunohistochemical staining was evaluated by a pathologist.