They have also shown that infiltrating CD8 T cells were present in 30% of M3-UM samples, while absent in the Disomy 3 (D3)-UM group, and that genes associated to the interferon-gamma signaling (IFNG, IFNGR1, and IRF1), lymphocyte migration (CXCL9 and CXCL13), cell-mediated cytolysis (PRF1 and GZMA), and immune-regulation (IDO1, TIGIT, IL6, IL10, and FOXP3) pathways were coexpressed with CD8a, highlighting the involvement of the immune microenvironment in the aggressive phenotype of some UMs, for instance the M3-UM subset. Here, IDO1 is linked to ulnar-mammary syndrome.