paraphrase the review in your own words? The tumor suppressor PTEN (phosphatase and tensin homolog deleted from chromosome 10), is a lipid phosphatase that converts phosphatidylinositol-3, 4, 5- triphosphate (PIP3) into phosphatidylinositol (4, 5)- diphosphate (PIP2). PTEN is well-known as the most highly mutated tumor suppressor gene in the p53-post era [66, 67]. Recently, three papers by Nadav Bar and Rivka Dikstein, Linhua Liu and colleagues, and Laura Poliseno and colleagues, have demonstrated that PTEN was a bona fide target of miR-22 in a small cohort of cancer cell lines that are driven from breast cancer, cervical cancer, prostate cancer, and bronchial epithelial cancer. These studies contradict a uniform role of miR-22, indicating that under certain circumstances, miR-22 may function as an oncogene because of its antagonistic effects on tumor suppressive PTEN signaling [26, 68, 69] (Fig. 3). Using various miRNA target prediction programs and/or RNAhybrid program for evaluating the minimum free energy hybridization, these three groups all found that miR-22-PTEN was a high scoring miRNA-target pair. Enforced or reduced expression of miR-22 in human HEK293T, cervical cancer HeLa and breast cancer MCF-7 cell lines (Nadav Bar and Rivka Dikstein), anti-benzo[a]pyrene-7, 8-diol-9, 10-epoxide (anti-BPDE)-induced transformed human bronchial epithelial cancer cell line 16HBE-T (Linhua Liu and colleagues) and prostate cancer cell line DU145 (Laura Poliseno and colleagues), revealed that miR-22 negatively regulated PTEN protein expression. Intriguingly, an inverse correlation between miR-22 and PTEN mRNA expression has been presented by Poliseno et al., while Liu et al. found that there was no change of PTEN mRNA expression regardless of miR- 22 levels. A similarly inverse association of miR-22 and J. Xiong PTEN protein levels was observed in 16HBE-T and its parental normal cell line16HBE (Linhua Liu and colleagues), and in several prostate cancer cell lines, prostate cell lines and a prostate tumor tissue microarray (Laura Poliseno and colleagues). Furthermore, the mature levels of miR-22 were significantly increased in these tumor cells versus their normal counterparts. In line with this result, a direct correlation between miR-22 expression and phosphorylated AKT or between the expression of miR- 22 and that of DICER was also identified by Laura Poliseno and colleagues. These three groups all showed that an intact binding site at the 3’UTR of PTEN mRNA was required for miR-22 targeting. Functional analyses showed that miR-22 could induce apoptosis, inhibited colony formation and suppressed motility of bronchial epithelial cancer cells (Linhua Liu and colleagues), and intrinsically promote prostate cancer cell growth and tumorigenesis in tumor- bearing nude mice (Laura Poliseno and colleagues). Subsequently, the influence of miR-22 on the downstream signaling of PTEN was tested. Bar et al. showed that miR-22 could stimulate AKT activity, and i.