However, β-catenin membranous immunoreactivity associated with E-cadherin decreased during transformation of normal endometrium through atypical endometrial hyperplasia to endometrial cancer in parallel with decreased E-cadherin expression in endometrial cancer [57]. CTNNB1 mutation is observed mainly in endometrioid endometrial cancer [57–59]. The gene discussed is CDH1; the disease is endometrial cancer.