Studies on the effect of IGFBP5 on cell growth suggest that its function as a promoter of growth inhibition or stimulation is cell-type specific [46,47], although a study by Butt et al. [48] demonstrated that in human breast cancer cells over-expression of this gene results in inhibition of cell growth and induction of apoptosis. The gene discussed is IGFBP5; the disease is breast carcinoma.