As a member of the ETS transcription factor family, FLI1 was known to regulate the expression of oncogenes, tumour suppressor genes, and some genes involved in maintaining vascular homoeostasis such as VE‐cadherin, platelet endothelial cell adhesion molecule 1.26, 28, 45 In GECs, we found that FLI1 was highly expressed and knockdown of FLI1 down‐regulated claudin‐5, occludin and ZO‐1 expression, which increased BTB permeability. The gene discussed is PECAM1; the disease is neoplasm.