Circulating leptin and inflammatory response in esophageal cancer, esophageal cancer-related cachexia-anorexia syndrome (CAS) and non-malignant CAS of the alimentary tract.

We investigated the association between esophageal cancer and cachexia-anorexia syndrome (CAS) of the alimentary tract and leptin, an adipocytokine crucial for body weight regulation, a modulator of inflammatory/immune response, implication of which in cancer and CAS development remains debatable. Circulating leptin was measured in 135 esophageal cancer patients (51 non-cachectic and 84 cachectic) and 83 controls (63 non-cachectic and 20 cachectic) and referred to cancer stage, CAS, and inflammatory and nutritional indices. Leptin was down-regulated in cancer patients and cachectic controls as compared to non-cachectic controls, with more pronounced hypoleptinemia in advanced cancers. Leptin correlated directly with BMI, TNF-alpha, albumin, and hemoglobin and indirectly with IL-6, IL-8, and hsCRP. The correlations, except for hsCRP, were more pronounced in females. BMI alone (females) and BMI and hsCRP (males) were independent predictors of leptin explaining over 60% of its variability. Following adjustment for BMI and gender, cancer-related CAS but not cancer itself negatively affected leptin. Leptin and BMI were independently associated with cancer-related and non-malignant CAS with diagnostic accuracy of 93% in identifying subjects with CAS. Pro-inflammatory, angiogenic and mitogenic properties of leptin do not seem to be important for esophageal cancer development but hypoleptinemia, independently from co-occurring reduction of adiposity, appears to be strongly associated with esophageal cancer-related CAS and non-malignant CAS of the alimentary tract.