RBM5 is a candidate tumor suppressor gene which encodes a nuclear RNA binding protein that is a component of the spliceosome A complex. RNA-binding protein 5 plays a role in the induction of cell cycle arrest and apoptosis through pre-mRNA splicing of multiple target genes including the tumor suppressor protein p53. RBM5 is located within the tumor suppressor region 3p21. , and may play a role in the inhibition of tumor transformation and progression of several malignancies including lung cancer.