GUCY2C and ganglioneuroma: Because the follicle-associated epithelium also shows strong expression of genes encoding specific ion channels, i.e., Cftr, Clca2, Kcnj15, and Kcna1 (Kobayashi et al. 2012), and we also found weak expression of Gucy2c in this region, it is conceivable that GN and UGN regulate ion transport across the follicle-associated epithelium through autocrine signaling.