Preliminary Results of Noninvasive Detection of TMPRSS2:ERG Gene Fusion in a Cohort of Patients With Localized Prostate Cancer

The positive immunostaining of TMPRSS2-ERG is not associated with unfavourable outcomes and biochemical recurrence after radical prostatectomy in Turkish patients

Introduction

Prostate cancer is the second most common cancer and a major significant health problem amongst men in the world. Radical prostatectomy with open, laparoscopic and robotic techniques is the gold standard treatment for localized and local advanced disease. There are some risk factors including gleason score, T stage and prostate-specific antigen (PSA) level to predict the biochemical recurrence. We investigated the association with biochemical recurrence and TMPRSS2:ERG fusion in patients who were treated with open radical prostatectomy.

Material and methods

The expression of TMPRSS2:ERG was defined as positive (Group 1) and negative (Group 2). The positive staining of the patients is classified into three groups; weak positive, moderate positive and strong positive. In the statistical analyses; chi squared test and Mann Whitney U were used and p <0.05 was defined as statistical significance.

Results

The present study includes 87 patients, 32 and 55 patients were in group 1 and 2 respectively. The mean age of the patients was 62.81 +5.55 and 64.45 +5.18 in the groups without significant difference. Extraprostatic extension was reported in 27 patients; 11 of these patients were in group 1 and 16 patients were in group 2 (p = 0.60). Biochemical recurrence was detected in 15 patients. Of these patients, 5 were in group 1 and 10 were in group 2 (p = 0.76).

Conclusions

The current study found no association between TMPRSS2:ERG fusion and biochemical recurrence and unfavourable pathological results in Turkish patients. Further research including a large number of patients from different regions of Turkey is needed to investigate the ERG status and biochemical recurrence for patients.

Association between TMPRSS2:ERG fusion gene and the prostate cancer: systematic review and meta-analysis

INTRODUCTION

To identify the association between the TMPRSS2:ERG fusion gene, their variants and the onset of localized prostate cancer.

MATERIAL AND METHODS

A systematic search strategy was carried out through MEDLINE, EMBASE, LILACS, CENTRAL and unpublished literature. We included randomized control trials, cohort, case-control and cross-sectional studies that involved patients >18 years-old assessing the association between TMPRSS2 fusion gene, its single nucleotide polymorphisms and prostate cancer. The primary outcome was prostate cancer defined by histology of the tumor coming from transrectal ultrasound guided biopsy, transurethral resection of the prostate or radical prostatectomy. We assessed the risk of bias with QUADAS2 and performed a meta-analysis with Stata 14.

RESULTS

We found 241 records with the search strategies. After duplicates were removed, 18 studies were included in qualitative analysis and 15 studies in meta-analysis. All included studies that had no applicability concerns and low risk of bias for flow and timing. Nine studies had an unclear risk of bias for index and reference tests, since they did not describe the blinding assessment appropriately. Regarding the association between TMPRSS2:ERG and prostate cancer, we found an odds ratio (OR) 2.24 and a 95% confidence interval (CI) (1.29 to 3.91). Regarding the kind of sample, urine showed an OR 2.79 and a 95% CI (1.12 to 6.98) and when using a DNA molecular template, the OR was 3.55 with a 95% CI (1.08 to 11.65).

CONCLUSIONS

There was an association between TMPRSS2:ERG fusion gene with the diagnosis of prostate cancer, mainly in urine samples and DNA-based molecular templates. TMPRSS2:ERG might be used as the gold standard biomarker for diagnosis and stratification of PCa.

Status of TMPRSS2-ERG fusion in prostate cancer patients from India: correlation with clinico-pathological details and TMPRSS2 Met160Val polymorphism

Background

Prostate cancer (PCa) shows considerable clinical heterogeneity that has been primarily attributed to variable molecular alterations. TMPRSS2-ERG fusion is one such molecular subtype that has been associated with predominantly poor prognosis. More recently, a single nucleotide polymorphism (SNP) in the TMPRSS2 gene rs12329760 C>T (Met160Val) has been shown to positively correlate with the fusion status and also to be associated with increased risk for PCa. The aim of the present study is to determine the frequency of TMPRSS2-ERG fusion and association of rs12329760 in Indian PCa patients with fusion status.

Methods

TMPRSS2-ERG fusion by fluorescence in situ hybridization was determined in 102 of 150 PCa biopsy-proven cases. Genotyping for rs12329760 was performed on the entire cohort of 150 cases by Sanger sequencing.

Results

TMPRSS2-ERG fusion was seen in 27 of 102 (26%) cases. Fusion-positive patterns in this study showed fusion by translocation in nine of 27 cases (33.5%), by deletion in six of 27 (22%) cases, and by insertion in 12 of 27 cases (44.5%). No association of the fusion status with Gleason Score, pattern, or perineural invasion was seen. The TMPRSS2 SNP rs12329760 'T' allele was prevalent with a frequency of 0.27 in the PCa patients. The SNP was significantly associated with fusion [odds ratio (OR) = 2.176, 95% confidence interval (CI) = 1.012-4.684, P = 0.04], more specifically fusion by deletion (P = 0.04).

Conclusion

The results provided here determine the frequency of TMPRSS2-ERG fusions (26%) in a fairly large cohort of Indian PCa cases and also the association of rs12329760 SNP with TMPRSS2-ERG fusion. No association with other clinico-pathological features was observed. Future studies with clinical outcomes are warranted in this population.