BCAR1 expression improves prediction of biochemical reccurence after radical prostatectomy

Abstract

Because prostate cancer exhibits a great variability in clinical outcome, biomarkers that can be used in daily practice are needed to better stratify patients into prognostic groups. Since steroid hormones play a central role in the development and progression of prostate cancer, we aimed to analyze in a matched nested case-control study the value of molecules involved in steroid signaling, to predict recurrence after radical prostatectomy, independently from standard prognostic tools. Among 1,200 patients treated by radical prostatectomy with negative margins with at least 4 years follow-up, 121 prostate cancers with biochemical relapse were matched after pathological reassessment with 121 cancers with identical clinicopathological features but without relapse. Immunohistochemistry was performed on tissue microarrays, using antibodies directed against molecules involved in androgen and estrogen signaling, including hormone receptors, enzymes (such as the five alpha reductases 1,2 and 3, aromatase, alpha-keto reductase 1C3 and squalene epoxidase), the breast cancer antiestrogen resistance 1 (BCAR1), and the proliferation marker Ki67. The median follow-up for patients without recurrence was 7 years. Both cell proliferation and BCAR1 expression were significantly associated with biochemical relapse, in univariate and multivariate analysis. In subgroup analysis, the sole predictive marker in patients with well-differentiated prostate cancer was BCAR1 (P = 0.004), whereas only proliferation (P = 0.001) was significantly associated with relapse in less-differentiated prostate cancer patients. BCAR1 is an independent predictor of recurrence after radical prostatectomy for "low risk" prostate cancer. The use of this biomarker may enable more individualized treatment approaches.