IGFBP-5. In breast cancer models, IGFBP-5 overexpression was strongly tumour inhibitory in vitro and in vivo [171], whereas the opposite effects were observed in some other cancer models, in which IGFBP-5 can stimulate IGF-dependent and IGF-independent cell survival and proliferation [172–175]. This evidence concerns the gene IGFBP5 and cancer.