The expression level of TGF-β is affected by FLCN mutations in BHD, and the aberrant expression of TGF-β is closely associated with the development of a variety of tumors, suggesting that deregulation of genes involved in TGF-β signaling by FLCN mutation was likely to be an important step in the development of renal tumors in BHD [27]. This evidence concerns the gene FLCN and kidney neoplasm.