The role of oxidative stress in the biology of melanoma: A systematic review.

Melanoma is the most aggressive skin tumour, which incidence is rising fast over the year. The metastatic stage of disease is extremely difficult to treat and the mortality rate is still high. Emerging evidence suggested that oxidative stress (OS) is involved in the pathophysiological pathways of several chronic diseases and in the transformation and progression of many common cancers, including melanoma. In particular, it has emerged that OS interacts with inflammatory and immune response, all taking part in the melanomagenic process. In light of the interest shown by the scientific community for this topic, it was analysed the association between melanoma and oxidative stress. A systematic review was performed according to PRISMA guideline employing PubMed database. It identified n = 29 articles which investigated this aspect. Melanoma cells resulted to have adaptive mechanisms to overcome effects of high reactive oxygen species (ROS) levels. Furthermore, OS influences the metastatic ability of melanoma cells and their resistance to therapy. Nonetheless, the included studies were conducted on heterogeneous patient population and with differences in the design of the studies and in the protocols. Therefore, it is mandatory performing further studies which analyze all the aspect of OS pathways: ROS imbalance, its effect to proliferation and metastasis, role of microenvironment, ROS effect to drug resistance. All this in order to understand the role of oxidative stress in the complex biology of melanoma and to provide possibilities of defining new strategy of therapy.