Alteration of Leptin and Adiponectin in Multistep Colorectal Tumorigenesis

There is an established link between obesity related metabolic derangement and colorectal cancer development. Recently, we developed a metabolic-colorectal cancer risk score. In this follow-up study, we studied its association with colorectal neoplasm by measuring two major metabolic syndrome biomarkers, leptin and adiponectin.

To evaluate the serum levels of leptin and adiponectin in patients with colorectal polyps and colorectal cancer and to determine any correlation with metabolic risk score.

In total, 130 individuals were studied: 30 controls without colonic pathology, 18 with colonic adenoma (CAP), and 82 with colorectal adenocarcinoma (CRC, 17 cases of T1-2 and 65 cases of T3-4). The metabolic risk scores in CAP and T1-2 CRC were higher than those in the controls and T3-4 CRC cases. There were no statistically significant differences in leptin levels among CAPs, CRCs, and controls. Both leptin and adiponectin levels reflected differences in body mass index and metabolic risk scores. Cases in the CAP group and early T-stage CRC groups had lower adiponectin levels (14.03 and 13.01 mg/ml, respectively) than the no polyps group (19.5mg/ml, p = 0.03). The average serum adiponectin level in the invasive cancer group (18.5 ng/ml) was comparable with that of the control group.

The level of serum adiponectin was positively correlated with the metabolic risk score. Decreased serum adiponectin was significantly associated with the development of colorectal adenoma and early stage colorectal carcinoma.