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Prostate Adenocarcinoma: Candidate Genomic Signatures Prognostic of Biochemical Failure

ABSTRACT: Prostate cancer is the most common form of non-skin cancer in American men. Although the 5-year survival rate is 100%, an important proportion of patients will recur after seven years following treatment. Despite attempts to delineate clinical and molecular prognostic signatures of recurrence, accurate prediction remains an elusive task. The purpose of this project was, therefore, to identify candidate genomic signatures of biochemical failure present at the moment of diagnosis. To do this, we carried out array comparative genomic hybridization on surgical specimens from a training cohort of patients with PRCA who were followed on average for ten years. Due to the unstable nature of malignant genomes, we selected non-random genomic aberrations through Significance Testing of Aberrant Copy Number (STAC), a statistical permutation algorithm. Further analysis of STAC regions between recurrent and non-recurrent groups showed that recurring cases had a greater proportion of gain in 4p14-12, 11p14.3-14.1 or 15q21.1-22.2 in comparison to non-recurrent cases. All three genomic signatures were independently, better predictors of recurrence than previously known clinical covariates. The importance of these regions in PRCA progression was further validated in publicly available expression data sets, where over-expression of ADAM10, BDNF and CYP19A1 (all coded in the aforementioned regions) was found to increase with progression of disease. We hypothesize that amplification of ADAM10, BDNF, and CYP19A1 may serve as candidate biomarkers of recurrence to be validated in larger datasets. Keywords: BAC Array CGH, Biomarker study

ORGANISM(S): Homo sapiens

PROVIDER: GSE7949 | GEO | 2007/08/01

SECONDARY ACCESSION(S): PRJNA100129

REPOSITORIES: GEO

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Project description:Background: Liver transplantation (LT) for Hepatocellular carcinoma (HCC) can be offered to patients beyond Milan criteria. However, there are currently no molecular markers that can be used on HCC explant histology to predict recurrence, which arises in up to 20% of LT recipients. The goal of our study was to identify proteins on HCC explant predictive of recurrence post-transplant, thereby guiding surveillance strategies and identifying patients beyond Milan criteria who would fare well following LT. Methods: LT recipients who had been transplanted at the University Health Network for HCC beyond Milan criteria in the context of Hepatitis B cirrhosis were identified. Snap-frozen samples from the dominant tumors of recurrent (N=7) and non-recurrent (N=4) patients were analyzed using LC-MS/MS on a Q-Exactive Plus mass spectrometer to delineate a distinctive proteomic signature. These tumors were also profiled by a Human Gene 2.0 ST microarray platform to identify a transcriptomic signature predictive of recurrence and analyzed with R packages. STRING database was used to characterize the implicated pathways. Kaplan-Meier estimator was used to generate a combined proteomic/transcriptomic signature predictive of HCC recurrence in patients with HCC beyond Milan criteria at time of LT. Significantly predictive proteins were verified and internally validated by immunoblotting or immunohistochemistry. Results: A total of 79 proteins and 636 genes were significantly differentially expressed in recurrent HCC, compared to non-recurrent (p<0.05). Among these, LGALS3, LGALS3BP, HAL, THBS1, and BLMH, were significantly increased in recurrent HCC at the protein and gene expression level. In turn, ALDH1A1 protein and gene expression were significantly decreased in recurrent HCC. Univariate survival analysis depicted ALDH1A1 (HR=0.084, 95%CI 0.01-0.68, p=0.02), LGALS3BP (HR=7.14, 95%CI 1.20-42.96, p=0.03), and LGALS3 (HR=2.89, 95%CI 1.01-8.3, p=0.049) as the key dysregulated proteins and genes in the patients with HCC recurrence versus those with non-recurrence by both proteomic and transcriptomic analysis. Decreased ALDH1A1 and significantly increased LGALS3 protein expression in recurrent HCC was verified by immunoblotting. Increased LGALS3BP protein expression in recurrent HCC was orthogonally verified and validated by immunohistochemistry in 30 independent HCC samples. Conclusion: Protein and gene expression of the cancer stem cell marker ALDH1A1 was protective against cancer recurrence in patients transplanted for HCC beyond Milan criteria. Conversely, increased expression of LGALS3 and LGALS3BP on explant was significantly predictive of post-transplant recurrence. These findings were internally validated, suggesting potential utility in identifying patients with HCC beyond Milan who would clearly benefit from transplant with limited recurrence risk and guiding post-transplant surveillance.

Project description:Background: Inter-patient prostate cancer (PrCa) heterogeneity results in highly variable patient outcomes. Multi-purpose biomarkers to dissect this heterogeneity are urgently required to improve treatment and accelerate drug development in PrCa. Circulating biomarkers are most practical for evaluating this disease. We pursued the analytical validation and clinical qualification of blood mRNA expression arrays. Methods: Whole blood samples were collected into PaxGeneTM tubes from PrCa patients: 31 good prognosis patients selected for active surveillance (AS) and 63 advanced castration resistant PrCa (CRPC) patients. RNA was extracted, amplified, biotinylated, and hybridised to Affymetrix U133plus2 microarrays and analysis of genome-wide expression profiles were analysed using Bayesian Latent Process Decomposition (LPD). Findings: LPD analysis of the mRNA expression data divided the evaluable patients (n=94) into 4 separate groups. LPD1 and LPD2 consisted almost entirely of CRPC patients (14/14; 17/18); LPD3 (15/31) and LDP4 (12/21) comprised both AS and CRPC. Ten patients were unclassifiable by LPD analysis. LPD1 CRPC patients had significantly poorer overall survival (median 10.7 months, CI-95% 4.2-17.2) than CRPC patients in LPD2 to 4 (median 26.5 months, CI-95% 18.1-34.9, p=0.00007). LPD 1 membership remained the strongest prognostic factor in a multivariate analysis (HR 5.0, CI-95% 2.1-11.9, p=0.0002). Gene signatures in the poor prognosis LPD group 1 were associated with increased CD71+ early erythroid cells and decreased B-cell and T-cell immune response. A 9-gene signature, that was validated by RT-PCR studies, classified patients as group LPD 1 with a very low misclassification rate (1.2%). Interpretation: Poor PrCa outcome can be predicted using gene expression signatures from whole blood and merits further evaluation in predictive and pharmacodynamic biomarker studies for novel anticancer drugs including immune therapies. 107 blood samples were collected in paxgene tubes from 94 prostate cancer patients (31 good prognosis & 63 advanced castration resistant PrCa). Replicates include 9 biological replicates and four technical replicates

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Prostate Adenocarcinoma: Candidate Genomic Signatures Prognostic of Biochemical Failure

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