PTEN and neoplasm: Tumor-derived exosomal miR-934 induced macrophage M2 polarization by regulating PTEN expression and activating the PI3K/AKT signaling pathway, and the polarized M2 macrophages could further induce premetastatic niche formation and CXCL13 secretion, leading to colorectal cancer liver metastasis (CRLM) and secondary hepatocellular carcinoma (96).