These experiments resulted in two important findings: (1) tumor development in this model of colorectal cancer, which is genetically relevant to the most common human colon cancer subtype, was driven by Lgr5+ cancer stem cells, and (2) tumors could be maintained by proliferative Lgr5− cells that were able to replenish the eliminated Lgr5+ cells. The gene discussed is LGR5; the disease is colonic neoplasm.