KLF4 and male reproductive organ cancer: As studies reported that phosphorylation of p21 by Akt activation keeps it in the cytoplasm for anti-apoptosis while non-phosphorylated p21 shuttled into the nucleus for G1-S phase arrest [24], we wondered whether suppression of KLF4/PI3K/Akt pathway by miR-7 restoration inhibits prostate tumorigenesis through p21.