They believed that after tumor cells colonized LNs, MHC-I expression was upregulated to avoid NK cell killing, and PD-L1 was upregulated to inhibit T cell function in response to IFN signals and to induce Treg differentiation, thus establishing a tolerant microenvironment and facilitating distant metastasis of this type of tumor cell [119]. Here, IFNA1 is linked to neoplasm.