CTNNB1 and breast cancer: In addition, in studies relating to human breast cancer cell lines, phosphoglucose isomerase (PGI), which is a functional analog of ManA/PMI, has been seen to down regulate E-cadherin/beta-catenin complex formation through inhibition of E-cadherin expression and enhancement of proteosomal degradation of beta-catenin (Wu et al., 2008; Funasaka et al., 2009; Jia et al., 2013).