Serum leptin: a marker of prostate cancer irrespective of obesity

High expression of leptin receptors have been observed in the prostate cancer in various clinical studies; however the association of serum leptin with carcinoma prostate remains unresolved. We studied association, between serum leptin and carcinoma prostate in Asian (Indian) population and its association with obesity.

30 prospective cases of cancer prostate and 30 age matched controls were included in this study. Body mass index (BMI) was estimated and categorized in 4 groups by WHO criteria. Waist hip ratio (WHR) was calculated and divided into three groups. Serum leptin was estimated by sandwich ELISA technique (DRG leptin ELISA kit, Marburg, Germany).

Both the groups were comparable for age, WHR and BMI. Serum leptin was significantly higher in patients with cancer prostate as compared to controls (median 14.18 ng/ml vs. 1.63 ng/ml; p< 0.001). The level of leptin was found to have positive correlation with BMI and WHR in controls (r=0.485, p=0.007; r=0.314, p=0.091, respectively) however, no correlation was observed in patients with cancer prostate (r=0.071, p=0.711; r=0.067, p=0.725, respectively). There was no correlation between leptin and PSA. The serum leptin level was not related to the Gleason's score and stage of the carcinoma.

This study shows that Prostate cancer is associated with raised serum leptin which is independent of obesity and serum PSA. It hints the role of leptin in pathogenesis of this tumor. It may not be a surrogate marker of aggressiveness. For validation, further studies including a large patient population is required.