Leptin and soluble leptin receptor in risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition cohort.
Aleksandrova K., Boeing H., Jenab M., Bueno-de-Mesquita HB., Jansen E., van Duijnhoven FJB., Rinaldi S., Fedirko V., Romieu I., Riboli E., Gunter MJ., Westphal S., Overvad K., Tjønneland A., Halkjær J., Racine A., Boutron-Ruault M-C., Clavel-Chapelon F., Kaaks R., Lukanova A., Trichopoulou A., Lagiou P., Trichopoulos D., Mattiello A., Pala V., Palli D., Tumino R., Vineis P., Buckland G., Sánchez M-J., Amiano P., Huerta JM., Barricarte A., Menéndez V., Peeters PH., Söderberg S., Palmqvist R., Allen NE., Crowe FL., Khaw K-T., Wareham N., Pischon T.
Leptin, a peptide hormone produced primarily by the adipocytes, is hypothesized to play a role in the pathogenesis of colorectal cancer (CRC). Soluble leptin receptor (sOB-R) may regulate leptin's physiologic functions; however its relation to CRC risk is unknown. This study explored the association of leptin and sOB-R with risk of CRC in a prospective nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. A total of 1,129 incident CRC cases (713 colon, 416 rectal) were matched within risk sets to 1,129 controls. Conditional logistic regression was used to calculate relative risks (RR) and 95% confidence intervals (CI). After multivariable adjustment including body mass index (BMI), waist circumference, and baseline leptin concentrations, sOB-R was strongly inversely associated with CRC (RR comparing the highest quintile vs. the lowest, 0.55; 95% CI, 0.40-0.76; P(trend) = 0.0004) and colon cancer (RR, 0.42; 95% CI, 0.28-0.63, P(trend) = 0.0001); whereas no association was seen for rectal cancer (RR adjusted for BMI and waist circumference, 0.83; 95% CI, 0.48-1.44, P(trend) = 0.38). In contrast, leptin was not associated with risk of CRC (RR adjusted for BMI and waist circumference, 0.85; 95% CI, 0.56-1.29, P(trend) = 0.23). Additional adjustments for circulating metabolic biomarkers did not attenuate these results. These novel findings suggest a strong inverse association between circulating sOB-R and CRC risk, independent of obesity measures, leptin concentrations, and other metabolic biomarkers. Further research is needed to confirm the potentially important role of sOB-R in CRC pathogenesis.