RBM5 protein is a negative regulator of cell proliferation: overexpression of the full length LUCA-15/RBM5 in breast cancer CEM-C7 and NSCLC A549 cells suppressed cell proliferation through induction of apoptosis and arrest of tumor cells at the G1 phase of the cell cycle [16]. Here, RBM5 is linked to non-small cell lung carcinoma.