NOS2 and ocular melanoma: The pathogenesis of OM includes the direct damage to the mucosa induced by oxidative stress and the activation of transcription factors, such as nuclear factor-kappa B (NF-κB), which increases the expression of proinflammatory mediators, including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) (8–10).