A microarray study in the TSU‐Pr1 bladder cancer cell line indicated that KLF5 induced the expression of TNFAIP2. 19 Then, we demonstrated that KLF5 and TNFAIP2 are coexpressed in breast cell lines and tumours, and KLF5 directly binds to the 2 Sp1 sites at the TNFAIP2 gene promoter to regulate its transcription. The gene discussed is KLF5; the disease is neoplasm.