The applicability of lncRNAs as biomarkers is well illustrated by PCA3 (prostate cancer gene 3), routinely used in clinical applications as a prostate cancer marker [152], for instance, for patients who obtain a negative result from a prostate biopsy together with a raised level of prostate-specific antigen (PSA) which may indicate undiagnosed cancer [153]. This evidence concerns the gene KLK3 and prostate cancer.