KLF4 and breast cancer: For example, the aberrant expression of KLF4 regulates tumor development by regulating the Notch1 pathway.8 Some studies have shown that KLF4 suppresses the proliferation of tumors, including breast, and liver cancer tumors.9, 10 In contrast, knockdown of KLF4 inhibits breast cancer metastasis mediated by the Notch pathway.11 These results indicated that KLF4 plays multiple roles in tumor development, including tumor initiation and metastasis.