IFNAR1 and neoplasm: Similar to the immediate tumor microenvironment, type I IFNs were shown to inhibit the pro-tumoral differentiation of neutrophils in the pre-metastatic organs, as shown in a previous study of Wu et al., where mice deficient in interferon-alpha/beta receptor (Ifnar1-/-) developed higher metastasis loads in a mammary and lung carcinoma mouse model (9).