Indeed, the high and continuous expression of Pax6 in ectodermal tissues, such as the cornea, corneal epithelium, ciliary epithelium iris, and lens, is indispensable for the expression of structural genes (crystallins and cell adhesion molecules), signaling molecules affecting ocular NC migration (reviewed in Cvekl and Callaerts, 2017) and auxiliary transcription factors, including Six3, cellular musculoaponeurotic fibrosarcoma (c-Maf) and prospero homeobox 1 (Prox1) (Cvekl et al., 2004). The gene discussed is PROX1; the disease is fibrosarcoma.