PCA3 and urinary system disorder: LncRNA prostate cancer antigen 3 (PCA3) has been approved by the U.S. FDA as a marker for the diagnosis of PCa, and has also been included in “Guidelines for Diagnosis and Treatment of Urological Diseases in China”18, announcing tremendous potential of lncRNA as a biomarker for the diagnosis and treatment of PCa, which is worthy of in-depth study.