FLI1 and neoplasm: In tissue sections from mice with breast cancer, lung cancer and melanoma, Nagai N et al. reported that the expression level of FLI-1 in ECs in the tumour microenvironment was significantly lower than that in ECs in non-tumour microenvironments; the downregulation of FLI-1 expression was caused in part by soluble factors in the tumour microenvironment [28], including TNF-α, IL-1β, and IFN-γ.