However, examination of Klf4 expression in a panel of human breast cancer cells showed no correlation between Klf4 and E-cadherin (Pearson correlation coefficient r = −0.05879, dataset GSE12777, 51 human breast cancer cells), indicating that although Klf4 was able to restore E-cadherin in mesenchymal breast cancer cells [25], it is not the essential transcription factor that determines the epithelial phenotype of breast cancer cells. This evidence concerns the gene CDH1 and breast cancer.