Expression analysis of S100 proteins and RAGE in human tumors using tissue microarrays.

Microarray technology provides important information for diagnostic, prognostic, and even therapeutic applications. Several S100 proteins have been proposed to play important roles in tumor progression and are recognized as potential tumor markers. To substantiate these limited earlier findings, we screened hundreds of tumor specimens from patients of eight different tumor types using tissue microarrays. The results validated the expression of S100A4, S100A6, and S100B in specific tumor types. A significant S100A2 expression was observed in lymphoma biopsies, which implies a possible link between this S100 protein and lymphoma development. In contrast, S100A5 and S100A12 were not significantly expressed in any of the tumor tissues tested. Interestingly, expression of RAGE (receptor for advanced glycation end products) was found in breast and lung tumor tissues where abundant S100A4 and S100A6 expression was also observed. This suggests a possible role of RAGE-mediated signal transduction in the development of these particular cancers.