Immunohistochemical Study on MAPK Expression in Seborrheic Keratosis and Squamous Cell Carcinoma by Sun Exposure / 대한피부과학회지

ABSTRACT

BACKGROUND: Mitogen-activated protein kinase (MAPK) is a key molecule in intracellular signal transducing pathways that transport extracellular stimuli from cell surface to nuclei. The MAPK family, comprised of extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 kinases, could be activated by a number of growth factors, cytokines, and other stimuli such as UV light, and has been implicated in the regulation of cell proliferation, tumorigenesis, differentiation, and apoptosis. OBJECTIVE: The purpose of this study was to immunohistochemically analyze the expression of ERK and JNK in epidermal tumors, including seborrheic keratosis (SK) and squamous cell carcinoma (SCC) on sun-exposed skin and unexposed skin. METHOD: SK on sun-exposed skin (5 cases) and unexposed skin (5 cases), and SCC on sun- exposed skin (5 cases) and unexposed skin (5 cases) were immunohistochemically stained with ERK and JNK monoclonal antibodies. RESULTS: ERK was more strongly expressed than JNK in all the cases. In the sun-exposed skin of SK and SCC, ERK was more definitely expressed than in the unexposed area. JNK was not expressed in all tumor cells of SK and SCC. CONCLUSION: This study strongly indicates that ERK expression may be related to sun exposure and responsible for proliferation of tumors. On the other hand, JNK may not be associated with tumor progression, caused by sun exposure.