A direct proof from Cittelly at al. [73] demonstrates that suppression of miR-29 potentiates dedifferentiation of breast cancer cells into tumorigenesis state (actually iBCSCs) via Krüppel-like factor 4 (Klf4), a transcription factor required for the reprogramming of differentiated cells into pluripotent stem cells. This evidence concerns the gene KLF4 and breast cancer.