“…For example, the amplification expression of mir-17, mir-21 and mir-155 relatively cause tumour initiation and progression by inhibiting the expression of tumour suppressor genes, such as phosphatase and tensin homologue (PTEN), and programmed cell death 4 (PDCD4) (Meng et al, 2007;Petrocca et al, 2008;Frankel et al, 2008). In contrast, p53, also known as tumour protein 53, and is a tumour protein that in humans is encoded by the TP53 gene (McBride et al, 1986), is the most important and well-studied cancer gene that regulates the cell cycle involved in preventing cancer. Fundamentally, the action of p53 is to induce the expression of miRNAs, best described by the miR-34 family, which represses genes that can promote proliferation and apoptosis (He et al, 2007).…”