In melanoma patients, melanoma antigen recognised by T cells 1 (MART-1), paired box gene 3 (PAX3), and melanoma associated antigen 3 (MAGE-A3) mRNA expression in CTCs was evaluated for utility as ICI biomarkers [90] and recently β-catenin (CTNNB1) overexpression in CTCs was found to be associated with progressive disease of stage III/IV melanoma patients treated with ICI [91]. This evidence concerns the gene CTNNB1 and melanoma.