Analysis of cancer-testis antigens as potential markers for dissemination of primary human skin melanoma

Purpose of the study: to analyze characteristics of cancer-testis antigens (CTAs) as potential biomarkers for dissemination of primary human skin melanoma (SM). Material and Methods. Recent publications from Pubmed, Scopus and eLibrary databases were analyzed for the available appropriate literature review. In total, 176 papers reported the description of CTAs and encoding genes and their potential for prognosis of primary SM dissemination. The authors included 52 of them in the given review. Results. Two sections of the paper comprise clinically significant characteristics of CTAs and their genes, including overexpression, which is selective for the heterogeneous tumor cell populations and mediated by humoral and/or cellular immune reactions; the association of tumor process and activation of CTA genes by demethylation of promotor sites, which is correlated with tumor progression; and the conditions required for effective immunotherapy involving CTAs and/or their genes. Conclusion. At present, there are no standards or clinical recommendations for the CTA-based prognosis of the early dissemination of primary skin melanoma. Therefore, it is important to study and analyze the CTA and encoding gene characteristics that reveal the connection between primary SM progression and tumor genesis including the role of circulating tumor cells (CTC), similar to stem cells, which have epithelial-mesenchymal transition (EMT) phenotype, for clinical diagnostics of early SM dissemination. As a result of the study, the following CTAs could be considered as significant biomarkers of the early SM dissemination: MAGE-A1, MAGE-A4 and NY-ESO-1, which expression correlates with the clinical pathological description of the disease progression, as well as with the relapse-free period and overall survival of the patients; MAGEA3, which expression correlates with SPAG5 activation and CD8+ T-cell abundance; SSX, a marker for stem cell migration including identification of the cells with EMT and/or CTCs; and PRAME, signaling marker for dissemination of the uveal melanoma.