Specifically, total IGF-I concentrations are positively associated with the risk of prostate, colorectal and pre-menopausal breast cancers, but not lung cancer, while total IGFBP-3 concentrations are positively associated with the risk of pre-menopausal breast cancer, and, after excluding a recruitment-bias study, inversely associated with lung cancer risk. The gene discussed is IGF1; the disease is breast cancer.