To better understand the role of the tumor microenvironment on the development and proliferation of cNF, future studies should identify what extrinsic signals regulate cNF formation, which includes understanding the cell source of these signals, the timing of these signals, if biallelic inactivation in the cells is important, and elucidating the role of soluble signaling molecules, ECM, and cell contact. This evidence concerns the gene NPHS1 and neoplasm.