Serum levels of leptin receptor in patients with malignant melanoma as a new tumor marker

Leptin is known to be abnormally expressed in a variety of cancers, and leptin receptors have been reported to be expressed on human melanoma cells. In this study, we evaluated the possibility that the serum levels of leptin receptor could be a tumor marker of malignant melanoma (MM). Serum samples were obtained from 71 patients with MM, and the serum levels of leptin receptor were measured by double‐determinant ELISA. Interestingly, serum levels of leptin receptor decreased gradually with the stages of MM, being highest at in situ and lowest at stage IV. There was also a trend of reverse correlation between tumor thickness and serum levels of leptin receptor. To our knowledge, this is the first report investigating the serum levels of leptin receptor in MM, and serum leptin receptor levels may be used as a useful tumor marker of MM.