Up-regulation of intercellular adhesion molecule-1 (ICAM-1) and cytokines associated with Th 1 immune response, such as interferon (IFN)-gamma, tumour necrosis factor (TNF)- alpha, interleukin (IL)-1 alpha, IL-6 and IL-8, may also play a role in the pathogenesis of lichen planus (Chen et al., 2007). The gene discussed is ICAM1; the disease is lichen planus.