A causal relationship between DR inactivation and tumor progression was, for example, demonstrated in the case of UNC5C, which is downregulated via LOH and epigenetic silencing in colorectal cancer, whereby in vivo UNC5C inactivation increased tumor progression and decreased apoptosis in an APC1638N spontaneous intestinal tumors mouse model. The gene discussed is UNC5C; the disease is colorectal cancer.