LEP and nutritional deficiency disease: The mechanism by which cachexia promotes tumor invasion and metastasis is not yet clear, but it may be related to the inflammatory response, hypoxic state, decreased leptin levels and release of pro-angiogenic factors in cachexia patients.[8] Consequently, a vicious cycle occurs, with malnutrition from insufficient dietary intake resulting in increasing therapy toxicity and the unmanaged tumor causing even more severe malnutrition.