Cancer Immunomics to Identify Autoantibody Signatures
Cancer immunomics has been used to identify autoantibody signatures produced in response to the presence of either breast or colorectal cancer. SERological proteome analysis (SERPA) is performed by 2D GE, immunoblotting, image analysis, and MS (Hardouin et al. 2007). Alternatively, to identify the antigens recognized by the autoantibodies of cancer patients, an approach has been developed that combines 2D immunoaffinity chromatography, enzymatic digestion of the isolated antigens, nano flow separation of the resulting peptides, and identification: MAPPing (multiple affinity protein profiling). By these approaches both proteins recognized by autoantibodies independently of a cancer status are identified as well as a limited number of proteins reacting preferentially with cancer sera.
Desorption Electrospray Ionization for Detection of Cancer Biomarkers
A modified mass spectrometry (MS) technique, desorption electrospray ionization (DESI), involves aiming a fine water mist at a surface with a pencil-sized tube that also sucks up the fluid after the droplets have mixed with the material in the sample. Whereas ordinary MS is both time- and labor-intensive, DESI not only is portable, but they can also determine the chemical composition of an unprepared sample within five seconds. Thus DESI can detect chemical signature of cancer in liver tissue. The technique can tell the difference between diseased and non-diseased regions of tissue samples within a few seconds. Another advantage of DESI is that it can detect lipid biomarkers whereas conventionl MS is good at detection protein biomarkers. Cancerous regions possess higher levels of certain lipid molecules, which could indicate a significant relationship between lipids and tumor proliferation. The devices might one day prove useful in helping surgeons ensure that all of the tumor is destroyed before a patient leaves surgery and also to identify other potential tumor sites in the tissue that are indistinguishable to the naked eye. It would help physicians determine how well a drug is working in different organs of the body. Analysis of different regions in a tissue sample would facilitate evaluation of the mechanism of its drug action and its effectiveness.