Emilie Lalonde

Crowdsourced estimation of cognitive decline and resilience in Alzheimer's disease

Identifying accurate biomarkers of cognitive decline is essential for advancing early diagnosis and prevention therapies in Alzheimers disease. The Alzheimers disease DREAM Challenge was designed as a computational crowdsourced project to benchmark the current state‐of‐the‐art in predicting cognitive outcomes in Alzheimers disease based on high dimensional, publicly available genetic and structural imaging data. This meta‐analysis failed to identify a meaningful predictor developed from either data modality, suggesting that alternate approaches should be considered for prediction of cognitive performance.

TMPRSS2-ERG Status Is Not Prognostic Following Prostate Cancer Radiotherapy: Implications for Fusion Status and DSB Repair

Background: Preclinical data suggest that TMPRSS2-ERG gene fusions, present in about 50% of prostate cancers, may be a surrogate for DNA repair status and therefore a biomarker for DNA-damaging agents. To test this hypothesis, we examined whether TMPRSS2-ERG status was associated with biochemical failure after clinical induction of DNA damage following image-guided radiotherapy (IGRT). Methods: Pretreatment biopsies from two cohorts of patients with intermediate-risk prostate cancer [T1/T2, Gleason score (GS) < 8, prostate-specific antigen (PSA) < 20 ng/mL; >7 years follow-up] were analyzed: (i) 126 patients [comparative genomic hybridization (CGH) cohort] with DNA samples assayed by array CGH (aCGH) for the TMPRSS2-ERG fusion; and (ii) 118 patients [immunohistochemical (IHC) cohort] whose biopsy samples were scored within a defined tissue microarray (TMA) immunostained for ERG overexpression (known surrogate for TMPRSS2-ERG fusion). Patients were treated with IGRT with a median dose of 76 Gy. The potential role of TMPRSS2-ERG status as a prognostic factor for biochemical relapse-free rate (bRFR; nadir + 2 ng/mL) was evaluated in the context of clinical prognostic factors in multivariate analyses using a Cox proportional hazards model. Results: TMPRSS2-ERG fusion by aCGH was identified in 27 (21%) of the cases in the CGH cohort, and ERG overexpression was found in 59 (50%) patients in the IHC cohort. In both cohorts, TMPRSS2-ERG status was not associated with bRFR on univariate or multivariate analysis. Conclusions: In two similarly treated IGRT cohorts, TMPRSS2-ERG status was not prognostic for bRFR, in disagreement with the hypothesis that these prostate cancers have DNA repair defects that render them clinically more radiosensitive. TMPRSS2-ERG is therefore unlikely to be a predictive factor for IGRT response. Clin Cancer Res; 19(18); 5202–9. ©2013 AACR.

BPG: Seamless, Automated and Interactive Visualization of Scientific Data

We introduce BPG, an easy-to-use framework for generating publication-quality, highly-customizable plots in the R statistical environment. This open-source package includes novel methods of displaying high-dimensional datasets and facilitates generation of complex multi-panel figures, making it ideal for complex datasets. A web-based interactive tool allows online figure customization, from which R code can be downloaded for seamless integration with computational pipelines. BPG is available at http://labs.oicr.on.ca/boutros-lab/software/bpg

Abstract A28: Mutational landscape of TP53 in localized prostate cancer

Background: We performed a comprehensive interrogation of the mutational landscape of TP53 in the context of localized prostate cancer using a large clinical/molecular-paired dataset from the Canadian Prostate Cancer Gene Network (CPC-GENE). We further test the associations of TP53 mutations with outcomes post-image-guided radiotherapy (IGRT) or radical prostatectomy (RadP). Methods: Copy number status (N = 284), single nucleotide variants (SNV) (N = 123), methylation status (N = 117), and mRNA abundance profiling (N = 115) were assessed using the Affymetrix Oncoscan FFPE express v3.0 assay, whole genome sequencing (up to 100-200x), Illumina 450K methylation array, and Affymetrix HuGene 2.0 array, respectively. Patient cohort comprised of NCCN-defined intermediate-risk prostate cancer who underwent either IGRT (N = 146) or RadP (N = 137). Biochemical-relapse free rate (bRFR) was assessed as the primary clinical end-point. Results: We identified 65 cases (22.9%) with mono-/bi-allelic copy number alteration (CNA) of TP53, and 7 cases (5.7%; 6 non-synonymous and 1 splice variant) with TP53 SNV in our cohort, which was comparable with the TCGA (30% CNA, 7% SNV) and MSKCC (17% CNA, 2.9% SNV) cohorts of low to high-risk localized prostate cancers. Epigenomic profiling revealed specific sites of DNA hypermethylation (β-value >0.7) within the body and 59 UTR gene-regions, while the TSS gene-region was unaffected. Genomic mutations (CNA and/or SNV) of TP53 were associated with global genomic instability (percent genome aberration of 9.5 vs 6.4, p = 0.001) and reduced mRNA levels (mRNA abundance Z-Score: -0.58 vs 0.22, p-value = 0.0011), but methylation status had no consequence on these indices. Neither TP53 genomic mutations (HR = 1.35, 95% CI 0.91-2.00, Wald9s p = 0.14) nor mRNA abundance (HR = 1.39, 95% CI 0.71-2.75, Wald9s p = 0.34) was associated with bRFR on multivariable analyses. However, stratification by combinatorial genomic and mRNA abundance indices identified an unfavorable subgroup that was associated with poorer bRFR on multivariable analysis (HR = 2.95, 95% CI 1.42-6.12, Wald9s p = 0.004). Conclusions: This is the first comprehensive interrogation of the mutational landscape of TP53 in localized prostate cancer. Our findings suggest that functional TP53 loss at both the copy number and transcription level accounts for a subset of non-indolent localized prostate cancer. Citation Format: Osman Mahamud, Melvin L.K Chua, Stephane Supiot, Emilie Lalonde, Alan Dal Pra, Alejandro Berlin, Michele Orain, Valerie Picard, Helene Hovington, Alain Bergeron, Yves Fradet, Bernard Tetu, Gaetano Zafarana, Alice Meng, Julie Livingstone, Melania Pintilie, Michael Fraser, Theodorus van der Kwast, Paul C. Boutros, Bristow G. Robert. Mutational landscape of TP53 in localized prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on DNA Repair: Tumor Development and Therapeutic Response; 2016 Nov 2-5; Montreal, QC, Canada. Philadelphia (PA): AACR; Mol Cancer Res 2017;15(4_Suppl):Abstract nr A28.

Abstract 4339: Prognostic significance of copy number alteration burden in unfavorable intermediate-risk prostate cancers harboring intraductal carcinoma and cribriform architecture

Proceedings: AACR 107th Annual Meeting 2016; April 16-20, 2016; New Orleans, LAnnAim: Men with intermediate-risk prostate cancer represent a heterogeneous group of patients with varying prognoses. Intraductal carcinoma (IDC), cribriform architecture (CA), and high copy number alteration burden are novel pathological and genomic indices that predict aggressive disease and inferior clinical outcomes in patients with localised prostate cancer. We aimed to test the independent prognostic effect of these indices in a cohort of intermediate-risk prostate cancers.nnExperimental methods: We defined a set of clinical and genomic indices to test for their prognostic significance in a cohort of individuals with NCCN-defined intermediate-risk prostate cancer, who were treated with radical prostatectomy (RadP) or radiotherapy (RT) (N = 173, RadP; N = 358, RT). Clinical indices include primary T-category, pre-treatment PSA level, Gleasons score and pattern, and presence of IDC and/or CA. Pathological features were reviewed centrally by two expert pathologists. Copy number alteration burden was assessed in 215 tumours of the cohort using SNP array profiling (Affymetrix Oncoscan), and reported as percent genome aberration (PGA). Our primary endpoint was to test if a model incorporating IDC/CA and PGA stratifies patients with intermediate-risk disease for risk of biochemical relapse after primary treatment.nnResults: Biochemical relapse was associated with PGA on univariable and multivariable analysis for the sub-cohort of 215 patients (HR of High vs Low PGA defined by median = 1.61, 95% CI = 1.04-2.49, Walds p = 0.033). Based on modelling of the clinical indices, presence of IDC/CA was associated with biochemical relapse-free rate (bRFR) on univariable and multivariable analyses (HR = 1.90, 95% CI = 1.34-2.69, p = 0.00034), along with PSA level. Risk stratification considering both IDC/CA and PGA indicated an additive prognostic effect of IDC/CA to PGA for early biochemical relapse, with 18-month bRFR of 83% in High PGA, present IDC/CA vs 94% in Low PGA, absent IDC/CA subgroups (HR = 2.55, 95% CI = 1.49-4.39, p = 0.00069). A comparison of risk stratification models revealed that inclusion of PGA to IDC/CA yielded the strongest model for predicting 18-month bRFR in patients with intermediate-risk prostate cancer following treatment (area under the curve, AUC = 0.580, 95% CI = 0.456-0.675 [T-category, PSA, and IDC/CA] vs 0.649, 95% CI = 0.476-0.776 [T-category, PSA, IDC/CA, and PGA]).nnConclusions: We herein demonstrate for the first time a novel risk stratification model integrating pathological (IDC/CA) and genomic (PGA) indices to identify patients with unfavourable intermediate-risk prostate cancer, who may benefit from intensification to conventional definitive treatment.nnCitation Format: Melvin Lee Kiang Chua, Jure Murgic, Melania Pintilie, Emilie Lalonde, Charlotte Kweldam, Winnie Lo, Alejandro Berlin, Alan Dal Pra, Michele Orain, Valerie Picard, Helene Hovington, Alain Begeron, Yves Fradet, Bernard Tetu, Julie Livingstone, Alice Meng, Jun Yan Zhang, Gaetano Zafarana, Neil Fleshner, Mike Fraser, Paul Boutros, Robert Bristow, Theodorus van der Kwast. Prognostic significance of copy number alteration burden in unfavorable intermediate-risk prostate cancers harboring intraductal carcinoma and cribriform architecture. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4339.

Abstract 2966: The mutational landscape of localized gleason 6 and 7 prostate cancer

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PAnnProstate cancer (CaP) remains the most common male malignancy worldwide, leading to over 300,000 deaths per year. In Western countries, most prostate tumours are diagnosed while they are confined to the prostate and have relatively indolent histology, as assessed by the Gleason Score (GS). CaP is a C-class tumour, characterized by large number of driver copy-number aberrations and genomic rearrangements. Therefore, while previous sequencing studies have focused largely on the coding regions of late-stage disease, herein we comprehensively characterized the copy-number profiles of 250 localized prostate cancers and analyzed the whole genomes of 124 matched tumour/normal pairs derived from patients with GS6 and GS7 prostate cancer. Using this – the largest whole-genome sequencing dataset of prostate cancer to date – we confirm the C-class character of the disease and identify strong genomic subtypes that stretch across multiple types of somatic alteration, including SNVs, CNAs and genomic rearrangements. We provide the first assessments of localized hyper-mutation phenomena (chromothripsis and kataegis) in prostate cancer, and identify specific genes driving higher levels of these hyper-mutations. We identify unexpected biases in the location and role of both non-coding SNVs and genomic rearrangements, including clear association with epigenetic processes, and with genome-wide profiling of methylation in 92 samples. Finally, we demonstrate a stark paucity of clinically-actionable mutations in localized GS6 and GS7 disease, even lacking those common in high-risk localized disease, indicating that novel therapeutic development against the recurrent targets identified here will be key to allowing less-aggressive, targeted treatment of early-stage disease.nnCitation Format: Michael E. Fraser, Veronica Y. Sabelnykova, Takafumi N. Yamaguchi, Alice Meng, Lawrence E. Heisler, Junyan Zhang, Julie Livingstone, Vincent Huang, Andre P. Masella, Fouad Yousif, Michael Xie, Nicholas J. Harding, Xihui Lin, Haiying Kong, Stephenie D. Prokopec, Alejandro Berlin, Dominique Trudel, Xuemei Luo, Timothy E. Beck, Richard de Borja, Alister DCosta, Robert E. Denroche, Natalie S. Fox, Emilie Lalonde, Ada Wong, Taryne Chong, Michelle Sam, Jeremy Johns, Lee Timms, Nicholas Buchner, Michele Orain, Valerie Picard, Helene Hovington, Kenneth C. Chu, Christine Png, Bryan Lo, Francis Nguyen, Kathleen E. Houlahan, Christopher Cooper, Shaylan K. Govind, Clement Fung, Louis Lacombe, Colin C. Collins, Yves Fradet, Bernard Tetu, Theodorus van der Kwast, John McPherson, Thomas J. Hudson, Rob G. Bristow, Paul Boutros. The mutational landscape of localized gleason 6 and 7 prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2966. doi:10.1158/1538-7445.AM2015-2966

Abstract B129: Clinical implications of inter- and intra- prostatic heterogeneity.

Men with localized prostate cancer vary widely in clinical outcome, with a 30-50% failure rate after primary treatment. There is thus significant interest in developing genomically refined prognostic groups. We sought to evaluate the extent of genetic heterogeneity, both between patients (inter-prostate) and within individual prostate glands (intra-prostate) to assess the impact of genetic heterogeneity on risk stratification within a tight clinical cohort. Copy number aberrations (CNAs) from 75 Gleason 7 patients were determined by OncoScan SNP microarrays. We measure the percentage of genome involved in a CNA, termed percent genome aberration (PGA), a proxy for genomic instability. Additionally, whole genome sequencing was applied to 10 intermediate-risk prostate tumours and matched blood, including multiple manually macro-dissected regions from 5 of the prostates (range 2 to 9). Somatic single nucleotide variants (SNVs) and genomic rearrangements (GR) were extracted from each patient. We find a high degree of inter-prostatic heterogeneity between the 75 Gleason 7 patients, with the number of CNAs per patient ranging from 0 to 929, corresponding to PGA 0 to 16.7%. Known prognostic markers can differentiate between patients at higher risk for biochemical recurrence, but only account for a fraction of the cohort. Notably, when these prognostic genes are examined within multiple regions of five independent tumours, they differ in copy number between cancerous regions of the same prostate. For example, TP53 is deleted in 1/2, 1/3, 4/9, 0/4, and 4/5 prostate regions. Indeed, phylogenetic analysis of geographically distinct regions revealed multi-clonal disease in two of the five patients; separate analyses based on SNVs, CNAs, and GRs all concluded that these patient have two genetically distinct cancers within their prostate. We demonstrate dramatic levels of inter- and intra- prostate genetic heterogeneity within pathologically identical or similar cancers. The observed intra-prostatic genomic heterogeneity, both in terms of multi-focal and multi-clonal disease, has critical implications for clinical management. Prognostic information obtained by biopsy may be inconsistent depending on the site of biopsy, and applying personalized medicine to prostate cancer will be challenging. This study highlights the need for further evaluation of how intra-prostatic heterogeneity is related to patient prognosis. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B129. Citation Format: Emilie Lalonde, Paul C. Boutros, Michael Fraser, Richard de Borja, Nicholas J. Harding, Dominique Trudel, Alice Meng, Pablo H. Hennings-Yeomans, Andrew McPherson, Amin Zia, Jianxin Wang, Timothy Beck, Natalie S. Fox, Taryne Chong, Michelle Sam, Jeremy Johns, Lee Timms, Nicholas Buchner, Sohrab Shah, Cenk Sahinalp, Thomas J. Hudson, John D. McPherson, Theodorus van der Kwast, Robert G. Bristow. Clinical implications of inter- and intra- prostatic heterogeneity. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B129.

Abstract 2003: A molecular portrait of potentially curable prostate cancer.

Intermediate risk prostate cancer (CaP) with Gleason score (GS) of 7 show up to 100x variability in genetic instability. As CaP is multifocal and likely multiclonal, there is a need to characterize heterogeneity for patient stratification, which would increase the ability to act on genomic information by adding adjuvant therapies to offset systemic occult metastases that currently limit cure in ∼30% of patients. Individual genetic portraits could be used to improve cure on combined clinical-molecular staging criteria. We undertook a pilot study to assess the genetic heterogeneity of potentially curable GS=7 CaP. We selected 10 men with GS=7 CaP; 5 treated with external beam radiotherapy (frozen pre-treatment biopsies) and 5 treated with radical prostatectomy (RadP, frozen tumour). Additionally, DNA from 18 distinct formalin-fixed, paraffin-embedded (FFPE) foci from the 5 RadP were analysed. Each of these 28 foci were subjected to whole-genome sequencing (WGS) and OncoScan SNP arrays to yield comprehensive genetic profiles. mRNA expression was evaluated on frozen RadP by microarray. Germline DNA from whole-blood was also analysed. Following independent pathology reviews and manual macro-dissection of tumour areas of ≥70% cellularity, WGS (≥50x tumour, ≥30x germline) was performed on as little as 50 ng genomic DNA, and OncoScan arrays were performed using as little as 30ng DNA using either amplified or innate genomic DNA. Regions of CaP in FFPE RadP were recorded using a tissue map to identify independent malignant foci, and ERG immunostaining was performed to assist in the identification. In cases where ERG-positive and -negative foci were adjacent, ERG staining was repeated on an un-stained slide to confirm separate foci based on 3D multi-section analyses. ERG fusion status was also assessed in frozen samples by aCGH or IHC. Validation of SNVs via SNP array and deep-resequencing showed ∼99% accuracy. Tumour cellularity was estimated using Qpure and was >60% for all samples. Phylogenetic techniques were used to demonstrate clear multi-clonality in two tumours. Across all tumours, ∼50% of SNVs were specific to an individual tumour-region. Phylogenies were confirmed with both SNVs and CNAs, but CNAs generally exhibited greater concordance amongst different regions of the same tumour. Some previously observed recurrent mutations were previously identified as recurrent in CaP (e.g. SPOP), and the overall mutation rate for intermediate-risk CaP was only somewhat below that reported for castrate-resistant disease (11,230 somatic SNVs per tumour). Our studies support the concept that a complete characterization of inter- and intra-CaP heterogeneity is possible in fresh and archival tissues; the latter is important for correlations to clinical outcome. These approaches can then be streamlined for high-throughput analyses within personalized medicine laboratories leading to “point of care” molecular tests and individualization of therapy. Citation Format: Michael E. Fraser, Richard de Borja, Dominique Trudel, Nicholas J. Harding, Pablo H. Hennings-Yeomans, Alice Meng, Emilie R. Lalonde, Andrew Brown, Natalie S. Fox, Taryne Chong, Amin Zia, Michelle Sam, Jianxin Wang, Michelle A. Chan-Seng-Yue, Jeremy Johns, Lee Timms, Nicholas Buchner, Ada Wong, Fouad Yousif, Rob Denroche, Gaetano Zafarana, Maud HW Starmans, Hanbert Chen, Shaylan Govind, Francis Nguyen, Melania Pintilie, Neil Fleshner, Stanislav Volik, Lakshmi Muthuswamy, Colin C. Collins, Thomas J. Hudson, Lincoln D. Stein, Timothy Beck, John D. McPherson, Theodorus van der Kwast, Paul C. Boutros, Rob G. Bristow. A molecular portrait of potentially curable prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2003. doi:10.1158/1538-7445.AM2013-2003

Abstract 3184: Whole genome sequencing of low-input fresh frozen prostate cancer biopsies

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, ILnnProstate cancer is the most commonly diagnosed malignancy among men in the United States. Due to an aging population, prostate cancer incidence has been increasing, with an estimated 200,000 men being diagnosed in 2010 and more than 32,000 deaths resulting from this disease. Better predictors of patient prognosis and treatment outcome are required to individualize prostate cancer treatment. High-throughput genomic sequence-based approaches offer a unique opportunity to identify biomarkers of disease-progression, thereby enabling more individualized therapy. The Canadian Prostate Cancer Genome Network (CPC-GENE) is an outcomes-based initiative that will sequence 500 specimens from 350 prostate cancer patients over a 5-year time span. Previously, whole genome sequencing efforts from biopsy specimens have been hindered by insufficient quantities of extracted DNA required as input for sequencing library construction. As a proof of concept to demonstrate the ability to sequence low input amounts of DNA from prostate biopsies, whole genome sequencing has been initiated for 50 prostate tumor biopsy samples along with their matched blood-derived reference sample. An on-bead sample preparation protocol was optimized using decreasing quantities of input DNA and used to construct sequencing libraries from as low as 100ng of DNA derived from macrodissected fresh frozen prostate biopsies (>70% cellularity). Sequencing is performed on the Illumina HiSeq 2000 platform to generate coverage depths of 50x for tumor samples and 30x for reference samples. Following alignment using NovoAlign and variant-calling using GATK, we compared our results to genotyping-array results generated using the Affymetrix OncoScan platform. Single-nucleotide variants detected using arrays were validated >99% of the time by sequence data, confirming that the use of a low-input library did not hinder mutation detection. Sequencing does not exhibit significant genome-wide coverage biases, and CNV calls were compared between the genotyping arrays and the next-generation sequencing data. Outcomes from the sequencing and analysis of the initial 50 sample sets will similarly be applied over a 5-year period to characterize an additional 450 prostate specimens. The ability to whole genome sequence specimens where minimal amounts of extracted DNA exist presents new opportunities to sequence many samples previously deemed unusable, while also providing encouraging prospects for whole genome sequencing applications for future studies using biopsy specimens.nnCitation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3184. doi:1538-7445.AM2012-3184