The four genes up-regulated in BCBM in comparison to the primary BC were ARG2, SOX2, EGF and NCAM1 (FDR < 0.01 and log2 FC > 1.5, Supplementary Table S1, available at https://doi.org/10.1016/j.esmoop.2022.100636). This evidence concerns the gene SOX2 and breast cancer.