In conclusion, our findings that miR-7 negatively regulates the expression of the tumor suppressor KLF4 and that miR-7 overexpression promotes proliferation and migration of epithelial cells resulting in tumor formation in vivo, provide a mechanistic explanation for the aggressiveness of skin and lung tumors in which protein levels of KLF4 and Cyclin D have been shown to be down- and up-regulated, respectively [24], [25], [75]. Here, KLF4 is linked to neoplasm.