Evaluation of serum fatty acid binding protein-4 (FABP-4) as a novel biomarker to predict biopsy outcomes in prostate biopsy naïve patients.

OBJECTIVES: To investigate the role of serum fatty acid-binding protein-4 (FABP-4) as a surrogate of obesity and metabolic syndrome in the prediction of the outcome of prostate biopsy.

METHODS: A prospective pilot study was conducted for patients undergoing prostate needle biopsy (PNB) for clinically suspected prostate cancer (PCa) between June 2016 and August 2017. Fifty consecutive patients with biopsy-proven PCa were included as study group and 50 consecutive patients with negative biopsy were included as a control group. Receiver Operating Characteristic (ROC) curve was used to calculate the area under the curve (AUC) to compare the accuracy of the different parameters in the diagnosis as well as the presence of high-grade PCa (Gleason score 8-9) at PNB. Predictors of the outcome were analyzed using univariate and multivariate logistic regression analysis.

RESULTS: FABP-4 (AUC: 0.75; P < 0.001) and PSA-density (AUC: 0.84; P < 0.001) were the most accurate to detect PCa at PNB. On multivariate analysis, FABP-4 > 22.5 ng/ml (OR: 16.6; 95% CI 2.8-98; P = 0.002) and PSA-density > 0.38 ng/ml/ml OR: 17.7; 95% CI 5.3-59; P < 0.001) were independent predictors of PCa detection. Regarding high-grade PCa at PNB, FABP-4 (AUC: 0.79; P < 0.001) and %Free-PSA (AUC: 0.75; P < 0.001) were the most accurate. Independent predictors of high-grade PCa were FABP-4 > 32.3 ng/ml OR: 9.2; 95% CI 1.8-45; P = 0.006) and %Free-PSA ≤ 21.9 (OR: 5.5; 95% CI 1.1-27; P = 0.03).

CONCLUSIONS: FABP-4 is an independent predictor for both the diagnosis and high-grade Gleason score at PNB. This novel biomarker might have a promising role in optimizing PNB outcomes.