KLF4 and breast cancer: Malignant MDA-MB-231 breast cancer cells contain a large abundance of miR-10b, which can be released to the extracellular environment via exosomes and transferred to nonmalignant HMLE breast cells to suppress expression of homeobox D10 (HOXD10) and Kruppel-like factor 4 (KLF4), thereby promoting HMLE cell invasion and migration (Singh et al., 2014).