Since no in vitro experiments or nonmammalian model can replicate the complex processes of tumorigenesis in humans, the development of BHD-deficient animal models will shed light on the role of BHD in vivo and on the BHD-related biochemical pathways responsible for neoplasia, which eventually could lead to the development of therapeutic agents against BHD-related diseases. The gene discussed is FLCN; the disease is neoplasm.