PTEN genomic deletion is an early event associated with ERG gene rearrangements in prostate cancer.
OBJECTIVE
To investigate the interaction between, and significance of, ERG gene rearrangements and PTEN genomic deletions in relation to the development and progression of prostate cancer (PCA).


METHODS
We interrogated an initial cohort of 220 men with localized PCA using fluorescence in situ hybridization for ERG rearrangements and PTEN genomic deletions.


RESULTS
The incidences of ERG rearrangements and PTEN deletions in PCA were significantly higher than in high-grade prostatic intra-epithelial neoplasia (HGPIN) and benign prostate tissue (P < 0.001). ERG rearrangements and PTEN deletions were detected in 41.9 and 42.6% of patients' tumours, respectively. ERG rearrangements were never detected in benign prostate tissue, while PTEN aberrations were present at a basal level of 4.6%. PTEN hemizygous deletions showed higher frequency than homozygous deletions within each diagnostic category from benign prostate tissue to HGPIN and PCA (P ≤ 0.001). Furthermore, in 29 patients where all three tissues were available, PTEN genomic aberrations in PCA were significantly different from those in benign tissue (P = 0.005) and HGPIN (P = 0.02), reflecting the accumulation of genomic aberrations in the early stages of disease progression. Within this cohort, 71.4% of homozygous and 44.2% of hemizygous PTEN deletions occurred simultaneously with ERG rearrangements (P ≈ 0). Stratified according to Gleason score (GS), hemizygous PTEN deletions across various GS groups were observed at a higher frequency than homozygous deletions. However, PTEN homozygous deletions showed positive trends with higher GS, increasing in poorly differentiated PCA (GS 8-10) in comparison to moderately and well differentiated tumours (GS 6 and 7).


CONCLUSIONS
We show significant association between ERG gene rearrangements and PTEN genomic aberrations in subset of PCA. Our analysis also provides further support for the observation that homozygous PTEN deletions can occur within the subset of HGPIN lesions, and shows accumulating genetic aberrations with disease progression, evidenced by higher detection in PCA than in HGPIN and more PTEN homozygous deletions in GS 8-10 than in 6-7.
Bismar
Tarek A
TA
Department of Pathology and Laboratory Medicine, University of Calgary and Calgary Laboratory Services, Calgary, Alberta Canada. tarek.bismar@cls.ab.ca
Yoshimoto
Maisa
M
Vollmer
Robin T
RT
Duan
Qiuli
Q
Firszt
Matthew
M
Corcos
Jacques
J
Squire
Jeremy A
JA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015321:Gene Rearrangement / Q000235:genetics; D016678:Genome; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D051059:PTEN Phosphohydrolase / Q000235:genetics*; D011467:Prostate / Q000473:pathology*; D019048:Prostatic Intraepithelial Neoplasia / Q000235:genetics* / Q000473:pathology; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology; D017384:Sequence Deletion; D015534:Trans-Activators / Q000235:genetics*; D000071230:Transcriptional Regulator ERG
C072312:ERG protein, human; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human