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.
Keywords: Fluorescence in situ hybridization; Indians; Prostate cancer; Single nucleotide polymorphism; TMPRSS2–ERG; rs12329760.