The OX1R activation in colon cancer cells by exogenous orexins (OxA or OxB) induced the mitochondrial caspase-dependent apoptosis (28) The OxA/OX1R system was responsible for the anti-tumoral impact in preclinical models in which colon cancer cells were xenografted and also in preclinical models where pancreatic or liver cancer cells were xenografted (15, 19, 29). This evidence concerns the gene HCRTR1 and liver cancer.