- Implications for prostate cancer of insulin-like growth factor-I (IGF-I) genetic variation and circulating IGF-I levels. Johansson, M., McKay, J.D., Wiklund, F., Rinaldi, S., Verheus, M., van Gils, C.H., Hallmans, G., Bälter, K., Adami, H.O., Grönberg, H., Stattin, P., Kaaks, R. J. Clin. Endocrinol. Metab. (2007)