title: Serum sarcosine increases the accuracy of prostate cancer detection in patients with total serum PSA less than 4.0 ng/ml.
abstract: BACKGROUND
  Sarcosine is reported to be a differential metabolite that is greatly increased during prostate cancer (PCa) progression. In this study, we assessed the role of serum sarcosine as a biomarker for PCa, as well as any association between sarcosine levels and clinical-pathological parameters.
  
  
  METHODS
  Sarcosine was measured by fluorometric assay in serum samples from 290 PCa patients and 312 patients with no evidence of malignancy (NEM), confirmed by 8-12 core prostate biopsies. Nonparametric statistical tests and receiver operating characteristics (ROC) analyses were performed to assess the diagnostic performance of sarcosine in different (prostate-specific antigen) PSA ranges.
  
  
  RESULTS
  ROC analyses in subjects with PSA < 4 ng/ml showed a higher predictive value of sarcosine (AUC = 0.668) versus total PSA (AUC = 0.535) (P = 0.03), whereas for the other two PSA ranges (4-10 ng/ml and >10 ng/ml), percent ratio of free to total PSA (%fPSA) showed a predictive superiority over sarcosine. Moreover, in patients with a PSA < 4 ng/ml, the percentage of low/intermediate-grade cancers was positively associated with sarcosine levels (P = 0.005). The specificities for serum sarcosine, %fPSA, PSA, and the logistic regression model at 95% sensitivity were 24.4, 3.41, 2.22, and 28.4%, respectively.
  
  
  CONCLUSIONS
  We provide evidence that serum sarcosine has a higher predictive value than tPSA and %fPSA in patients with PSA < 4 ng/ml. Moreover, sarcosine levels were significantly different in low grade versus high grade cancers in this subset of patients, suggesting that this marker may be a further tool not only for diagnosing PCa in normal PSA and abnormal DRE/TRUS patients but also for selecting candidates for non-aggressive therapies and active surveillance.
authors.affiliation: Unit of Urology, Andrology and Kidney Transplantation, Department of Emergency and Organ Transplantation, University of Bari, Bari, Italy. giuseppe.lucarelli@inwind.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lucarelli
authors.forename: Margherita
authors.initials: M
authors.lastname: Fanelli
authors.forename: Angela Maria Vittoria
authors.initials: AM
authors.lastname: Larocca
authors.forename: Cinzia Annatea
authors.initials: CA
authors.lastname: Germinario
authors.forename: Monica
authors.initials: M
authors.lastname: Rutigliano
authors.forename: Antonio
authors.initials: A
authors.lastname: Vavallo
authors.forename: Francesco Paolo
authors.initials: FP
authors.lastname: Selvaggi
authors.forename: Carlo
authors.initials: C
authors.lastname: Bettocchi
authors.forename: Michele
authors.initials: M
authors.lastname: Battaglia
authors.forename: Pasquale
authors.initials: P
authors.lastname: Ditonno
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood*; D001706:Biopsy; D016022:Case-Control Studies; D018450:Disease Progression; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis*; D012372:ROC Curve; D015203:Reproducibility of Results; D012521:Sarcosine / Q000097:blood*
chemical_list: D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen; D012521:Sarcosine