These studies confirmed prior findings that EEC exhibits high frequencies of somatic alterations resulting in activation of the PI3-kinase pathway, the RAS-RAF-MEK-ERK pathway, and the WNT/β-catenin pathway, frequent mutations in ARID1A (BAF250A) tumor suppressor, and mismatch repair defects resulting in MSI [2,16–18]. The gene discussed is ARID1A; the disease is exstrophy-epispadias complex.