CDH1 and melanoma: Previous studies showed PEDF is a useful marker for monkey RPE polarization and increased in polarized human RPE cells compared with non-polarized RPE cells while losing apical-basal polarity is the important step during EMT.18, 26, 27 Orgaz et al.28 showed that PEDF expression was correlated with E-cadherin and N-cadherin in some pairing melanoma cells but not SBcl2 cells.