KLF5 and neoplasm: Despite the phased breakthroughs achieved in the research and development of KLF5 inhibitors, many challenges remain: some compounds have problems such as insufficient in vivo activity and poor targeting; the physiological functions of KLF5 in normal tissues may also lead to off-target toxicity of inhibitors; and the lineage plasticity of tumor cells may trigger acquired resistance to KLF5 inhibitors.