Characterization of Gleason Grade 3 Tumor in Localized and Advanced Prostatic Adenocarcinoma Using a Panel of Functional Gene Expression Markers
C Barrett, P Smyth, B Loftus, O Sheils, JJ O'Leary. Trinity College Dublin, Dublin, Ireland; Adelaide & Meath Hospital, Dublin, Ireland
Background: The natural history of prostate cancer is variable; with prediction for individual patients difficult. For example, many patients who present with low-stage, low-grade disease have tumors that behave in an indolent fashion. However, up to 30% of these patients will develop metastatic disease within 10 years. With this in mind, we examined the gene expression profiles of areas of Gleason grade 3 tumour in localized (Gleason score 6) [LC] and advanced (Gleason score 7) [AC] prostatic adenocarcinoma [PCa] to see if there are identifiable genetic differences that might contribute to a tumors propensity to clinically progress.
Design: Using formalin fixed paraffin embedded archival material total RNA was extracted from Gleason grade 3 areas of 20 cases of LC and 20 cases of AC (Gleason scores 6 & 7 respectively) and 9 control cases of benign prostatic hyperplasia (BPH). Extractions were carried out with Ambion RecoverAllTM Total Nucleic Acid Isolation Kit. TaqMan RT-PCR was used to interrogate the cohort of samples for gene expression of designated gene targets with the following molecular functions: [i] lipid metabolism (e.g. AMACR, ACSL3, CRAT ), [ii] stress response (e.g. BAX,BCL2, CDKN1A, GADD45B, HIF1A), [iii] detoxification (e.g. CAT, GPX6, GSTM2), [iv] cell cycle control (e.g. CCND1, CDK4, CDKN2A, ERB2, MDM2), and [v] PPAR regulated gene control (e.g. CITED2, MYC, CYP4A11, NFKB1, PIK3CA). Analysis of relative RNA expression data was performed using the 2- Ct method. CDKN1B was used as endogenous control. Statistical comparison between sample cohorts was performed using the Mann-Whitney two-tailed t-test.
Results: There was significant (p<0.05) upregulation of ACSL3, AMACR, CDKN2A, CRAT, ERB2, GADD45B, HIF1A, MYC in cases of LC compared with BPH. Upregulation of ACSL3, AMACR, CCND1, CDK4, CDKN2A, ERB2, CRAT, HIF1A and MYC and downregulation of GSTM2 was seen in cases of AC versus BPH. There was upregulation of BAX, CCND1, CDK4 and downregulation of CDKN1A, CITED 2 and GADD45B in cases of AC relative to LC.
Conclusions: LC and AC have distinctive lipid metabolism, stress response, cell cycle control, PPAR and detoxification gene pathway regulatory expression profiles relative to each other and BPH. These markers can be used to distinguish AC from LC or BPH and may have a role in the clinical progression of PCa from localized to advanced disease.
Category: Genitourinary (including renal tumors)
Wednesday, March 11, 2009 9:30 AM
Poster Session V # 119, Wednesday Morning