Protein abundance alterations in matched sets of macroscopically normal colon mucosa and colorectal carcinoma

Our current results, aimed at the detection of protein abundance alteration s that could be associated with the process of colon tumorigenesis, are sum marized. The matched sets of macroscopically normal colon mucosa and colore ctal carcinoma were examined by a one- or two-dimensional electrophoretic a pproach and proteins were identified using immunoblotting or mass spectrome try. The following results were observed: The levels of liver fatty acid-bi nding protein, actin-binding protein/smooth muscle protein 22-alpha and cyc looxygenase 2 were downregulated in colorectal carcinoma compared to normal colon mucosa. Conversely, the expression of a novel variant of heat shock protein70 and several members of the S100 protein family of calcium-binding proteins (two isoforms of S100A9, S100A8, S100A11 and S100A6) were upregul ated in transformed colon mucosa. Despite the variations of the levels of e xpression of given protein among analyzed samples, all quantitative changes were found to be statistically significant (Mann-Whitney test assuming p l ess than or equal to 0.05). We conclude that the proteomic approach is usef ul for the study of complex biological events underlying the process of col orectal tumorigenesis.