This cordon around the metastases might be caused by the presence of immunosuppressive factors such as PD-L1, IDO, IL-6 and Prostaglandin-E2 (PGE2) [2, 25], or extracellular matrix components (e.g. versican) [26] shown to be expressed by primary cervical tumor cells, leading to immunosuppressive cell subset accrual and preventing antitumor cell subsets to enter the tumor area. This evidence concerns the gene IDO1 and neoplasm.