SMAD7 and cancer: MiR‐17‐5p serves as an oncogenic miRNA to contribute to cancer development.30, 31 Numerous studies have already shown that miR‐17‐5p could modulate cell cycle to promote cell proliferation.32 Up‐regulation of serum miR‐17‐5p indicates a poor prognosis in various human cancers.33, 34 Consistently, miR‐17‐5p plays a pro‐fibrotic role in liver fibrosis.35 Previously, our group demonstrated that up‐regulation of miR‐17‐5p led to HSC activation through Smad7.24 Smad7 is known as a negative regulator in TGF‐β/Smads pathway.