MiR-1 was downregulated and acted as a tumor suppressor gene in hepatocellular carcinoma, colorectal cancer, prostate cancer, lung cancer, head and neck squamous cell carcinoma, rhabdomyosarcoma, bladder cancer and renal by targeting MET, FoxP1, HDAC4, Slug, PIK3CA, TAGLN2 et al [10-13, 28, 29]. The gene discussed is PIK3CA; the disease is prostate carcinoma.