Alternative splicing variants of human Fbx4 disturb cyclin D1 proteolysis in human cancer.

•The expression of Fbx4 was significantly lower in HCC tissues.•Novel splicing variants of Fbx4 were identified.•These novel variants are much more abundant in human cancer tissues and cells.•The novel Fbx4 isoforms could promote cell proliferation and migration in vitro.•These isoforms showed less capability for cyclin D1 binding and degradation.