Context: Causes of kidney cancer are not fully understood. Incidence is highest in those ages 50 to 70, and almost twice as high in men as in women. Smokers are twice as likely as non-smokers to develop renal cell carcinoma and about four times as likely to develop cancer of the renal pelvis. Insulin-like growth factor-I (IGF-I) has been shown to increase kidney microvascular growth and glomerular filtration rate, and its administration increases renal function in animal models of chronic renal failure, and has been proposed as a possible therapeutic agent (Hirschberg et al, 1998). However, the possible roles of IGF in the development of kidney cancer have not been well-studied. Objective: To examine the relation of serum levels of IGF-I and insulin-like growth factor binding protein 3 (IGFBP-3) to kidney cancer risk. Methods: We conducted a case-cohort study nested within the prospective Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study of 29,133 Finnish male smokers who were 50-69 years of age and not diagnosed with cancer at study entry. Serum concentrations of IGF-I, IGFBP-3 were measured in blood samples collected in 1985 to 1988. One hundred men were identified who had a diagnosis of kidney cancer >5 years after blood collection through the end of 1997. Self-reported information on lifestyle and medical history was collected and weight and height were measured at baseline. Multivariable logistic regression models were used to estimate the relative risk of kidney cancer associated with IGF levels. Results: A history of hypertension (known to be increased in those who are older, overweight, or heavier smokers) was more common among cases than among noncases. Men with IGF-I levels >108 ng/mL were 63% less likely to develop kidney cancer than men with IGF-I levels ≤108 ng/mL (OR=0.37; 95% CI=0.20-0.69). IGFBP-3 levels did not alter the association between IGF-I and kidney cancer risk. Further, no association was observed between IGFBP-3 levels and the development of kidney cancer. Conclusions: Low serum IGF-I levels in this cohort of older middle-aged male smokers are associated with increased kidney cancer risk, independent of IGFBP-3, age, anthropometry, lifestyle and medical history. Further research is needed to confirm the findings and examine the association in women and non-smokers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4830.