Epidermis-type 12-LO Background Information Epidermis-type 12-LO, also known as arachidonate 12-lipoxygenase or 12R-lipoxygenase, belongs to the lipoxygenase family. Lipoxygenases are enzymes which dioxygenate unsaturated fatty acids, thus initiating lipoperoxidation of membranes, the synthesis of signaling molecules as well as inducing structural and metabolic changes in the cell. The Lox enzymes in mammals, 12-LO and 15-LO, are classified with respect to their positional specificity of the deoxygenation of their most common substrate, arachidonic acid. The metabolism of arachidonic acid leads to the generation of biologically active metabolites that have been implicated in cell growth and proliferation, as well as survival and apoptosis. Epidermis-type 12-LO converts arachidonic acid to 12R-hydroxyeicosatetraenoic acid. This pathway is a regulator of cell survival and apoptosis and affects the expression and localization of the åv∫5 integrin and actin microfilaments in carcinoma cells.