Plasma sarcosine does not distinguish early and advanced stages of prostate cancer

The identification of prostate cancer remains problematic; no single, simple procedure exists for a reliable diagnosis. Prostate specific antigen (PSA), while non-invasive and easily measurable in serum, is not specific owing to false-positives from benign prostatic hyperplasia (BPH), inflammatory conditions and prostatic trauma. Additional diagnostic information must therefore be obtained by transrectal ultrasonography (TRUS) and digital rectal examination (DRE) to assess prostate size and morphology. Final confirmation of a malignancy requires histopathological analysis of several biopsies. A remaining hurdle in the identification process is the existence of indolent organ-confined disease and aggressive metastatic prostate cancer that can only be distinguished by additional imaging or nuclear medicine procedures. In a new approach to this diagnostic dilemma, it has been argued that screening for changes in metabolite expression resulting from gene silencing and gene activation could be used to identify a specific biological marker that increases in the transformation process. Therefore, a paper elaborating on metabolite expression in clinical samples of benign, localised and metastatic prostate cancer 1 was enthusiastically received and debated in editorials. 2-5