An increased level of circulating omentin was reported also in colon and colorectal cancer, gastric cancer, malignant pleural mesothelioma, and pancreatic adenocarcinoma [21, 22, 24, 27, 51], while in renal cell carcinoma it has been significantly lower as compared to control [26]. This evidence concerns the gene ITLN1 and hereditary clear cell renal cell carcinoma.