Molecular and clinico-histological data in aggressive prostate cancer patients from Bulgaria.

PURPOSE: Metastatic prostate cancer (PCa) is one of the leading causes of death in men worldwide. We report Bulgarian patients with strongly aggressive, castration-resistant PCa. METHODS: PCA3 overexpression, GSTP1 promoter hyper-methylation, TMPRSS2-ERG gene fusions, IVS1-27G>A in the KLF6 gene and mutations in androgen receptor (AR) gene, for diagnostic purposes were assessed. PCR, real-time PCR (RT-PCR), sequencing, and bisulfite conversion of DNA were applied. We correlated the molecular data to the histological and clinical findings. RESULTS: The obtained molecular profile in 11 PCa Bulgarian patients coincided with the clinico-histological data of strongly aggressive PCa. Association was detected between the tumor stage (assessed by TNM as T3 and T4) and the detected molecular profile of aggressive cancer behavior with one exception, assessed as T2. None of our patients had positive family history of prostate cancer and no somatic mutations were detected in the AR gene. All patients showed normal genotype with respect to the KLF6 IVS1- 27G>A polymorphism. The rest of the markers were positive in fresh prostatic tissues and biopsies from all patients, whereas only one blood sample showed triple positive result. CONCLUSIONS: The appearance of PCa-specific markers in blood was considered as a predictor for a PCa (micro) dissemination into the circulation. The GSTP1 promoter hypermethylation is the earliest epigenetic alteration, which indicates cancerous changes and the first and long-lasting marker that is detectable in blood circulation. The molecular profile needs to be strictly monitored during treatment, which is of great help in determining the patient's individual response to therapy.

Molecular and Clinicopathological Aspects of Prostate Cancer in Bulgarian Probands.

To correlate the molecular data to the clinicopathological parameters in Bulgarian prostate cancer patients. PCA3 overexpression, TMPRSS2-ERG gene fusion, GSTP1 promoter hypermethylation, somatic mutations in the AR gene and the IVS1-27G > A polymorphism in the KLF6 gene were studied. A total of 148 patients were analyzed: 16 aggressive PCa, 83 non-aggressive PCa, 25 BPH and 24 chronic inflammatory diseases. Real-time RT-PCR, DNA sequencing, and bisulfite conversion of DNA, were applied. All cases with aggressive PCa before treatment were tested positive for PCA3 overexpression, expression of a T2-ERG gene fusion product and GSTP1 promoter hypermethylation. No somatic mutations were detected in the AR gene and all patients showed normal KLF6-IVS1-27G > A genotype. The TMPRSS2-ERG positive status correlates with moderate to poorly differentiated prostate tumors and it is considered as unfavorable disease predictor. Positive GSTP1 promoter hypermethylation seems to be highly specific and the earliest epigenetic change in the prostate gland, which indicates the beginning of the pathological process. The appearance of positive molecular markers in blood was considered as a predictor of PCa dissemination. GSTP1 promoter hypermethylation was found as the earliest and a long-lasting epigenetic marker in blood samples of PCa patients, which makes it suitable as a marker for treatment follow-up. The molecular profile of prostate cancer needs to be strictly monitored during the course of disease treatment, which is of a great help in determining the patient's individual therapy response.