Showing papers by "Rehan Akbani published in 2014"

Comprehensive molecular characterization of gastric adenocarcinoma

Abstract: Gastric cancer was the world’s third leading cause of cancer mortality in 2012, responsible for 723,000 deaths1. The vast majority of gastric cancers are adenocarcinomas, which can be further subdivided into intestinal and diffuse types according to the Lauren classification2. An alternative system, proposed by the World Health Organization, divides gastric cancer into papillary, tubular, mucinous (colloid) and poorly cohesive carcinomas3. These classification systems have little clinical utility, making the development of robust classifiers that can guide patient therapy an urgent priority. The majority of gastric cancers are associated with infectious agents, including the bacterium Helicobacter pylori4 and Epstein–Barr virus (EBV). The distribution of histological subtypes of gastric cancer and the frequencies of H. pylori and EBV associated gastric cancer vary across the globe5. A small minority of gastric cancer cases are associated with germline mutation in E-cadherin (CDH1)6 or mismatch repair genes7 (Lynch syndrome), whereas sporadic mismatch repair-deficient gastric cancers have epigenetic silencing of MLH1 in the context of a CpG island methylator phenotype (CIMP)8. Molecular profiling of gastric cancer has been performed using gene expression or DNA sequencing9–12, but has not led to a clear biologic classification scheme. The goals of this study by The Cancer Genome Atlas (TCGA) were to develop a robust molecular classification of gastric cancer and to identify dysregulated pathways and candidate drivers of distinct classes of gastric cancer.

Comprehensive molecular profiling of lung adenocarcinoma: The cancer genome atlas research network

Abstract: Adenocarcinoma of the lung is the leading cause of cancer death worldwide. Here we report molecular profiling of 230 resected lung adenocarcinomas using messenger RNA, microRNA and DNA sequencing integrated with copy number, methylation and proteomic analyses. High rates of somatic mutation were seen (mean 8.9 mutations per megabase). Eighteen genes were statistically significantly mutated, including RIT1 activating mutations and newly described loss-of-function MGA mutations which are mutually exclusive with focal MYC amplification. EGFR mutations were more frequent in female patients, whereas mutations in RBM10 were more common in males. Aberrations in NF1, MET, ERBB2 and RIT1 occurred in 13% of cases and were enriched in samples otherwise lacking an activated oncogene, suggesting a driver role for these events in certain tumours. DNA and mRNA sequence from the same tumour highlighted splicing alterations driven by somatic genomic changes, including exon 14 skipping in MET mRNA in 4% of cases. MAPK and PI(3)K pathway activity, when measured at the protein level, was explained by known mutations in only a fraction of cases, suggesting additional, unexplained mechanisms of pathway activation. These data establish a foundation for classification and further investigations of lung adenocarcinoma molecular pathogenesis.

Comprehensive molecular characterization of urothelial bladder carcinoma

Abstract: Urothelial carcinoma of the bladder is a common malignancy that causes approximately 150,000 deaths per year worldwide. To date, no molecularly targeted agents have been approved for the disease. As part of The Cancer Genome Atlas project, we report here an integrated analysis of 131 urothelial carcinomas to provide a comprehensive landscape of molecular alterations. There were statistically significant recurrent mutations in 32 genes, including multiple genes involved in cell Users may view, print, copy, download and text and data- mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use: http://www.nature.com/authors/editorial_policies/license.html#termsThis paper is distributed under the terms of the Creative Commons. Attribution-Non-Commercial-Share Alike license, and the online version of the paper is freely available to all readers.

A pan-cancer proteomic perspective on The Cancer Genome Atlas

Abstract: Protein levels and function are poorly predicted by genomic and transcriptomic analysis of patient tumours. Therefore, direct study of the functional proteome has the potential to provide a wealth of information that complements and extends genomic, epigenomic and transcriptomic analysis in The Cancer Genome Atlas (TCGA) projects. Here we use reverse-phase protein arrays to analyse 3,467 patient samples from 11 TCGA 'Pan-Cancer' diseases, using 181 high-quality antibodies that target 128 total proteins and 53 post-translationally modified proteins. The resultant proteomic data are integrated with genomic and transcriptomic analyses of the same samples to identify commonalities, differences, emergent pathways and network biology within and across tumour lineages. In addition, tissue-specific signals are reduced computationally to enhance biomarker and target discovery spanning multiple tumour lineages. This integrative analysis, with an emphasis on pathways and potentially actionable proteins, provides a framework for determining the prognostic, predictive and therapeutic relevance of the functional proteome.

Characterization of HPV and host genome interactions in primary head and neck cancers.

Abstract: Previous studies have established that a subset of head and neck tumors contains human papillomavirus (HPV) sequences and that HPV-driven head and neck cancers display distinct biological and clinical features. HPV is known to drive cancer by the actions of the E6 and E7 oncoproteins, but the molecular architecture of HPV infection and its interaction with the host genome in head and neck cancers have not been comprehensively described. We profiled a cohort of 279 head and neck cancers with next generation RNA and DNA sequencing and show that 35 (12.5%) tumors displayed evidence of high-risk HPV types 16, 33, or 35. Twenty-five cases had integration of the viral genome into one or more locations in the human genome with statistical enrichment for genic regions. Integrations had a marked impact on the human genome and were associated with alterations in DNA copy number, mRNA transcript abundance and splicing, and both inter- and intrachromosomal rearrangements. Many of these events involved genes with documented roles in cancer. Cancers with integrated vs. nonintegrated HPV displayed different patterns of DNA methylation and both human and viral gene expressions. Together, these data provide insight into the mechanisms by which HPV interacts with the human genome beyond expression of viral oncoproteins and suggest that specific integration events are an integral component of viral oncogenesis.

Focal adhesion kinase: an alternative focus for anti-angiogenesis therapy in ovarian cancer.

Abstract: This investigation describes the clinical significance of phosphorylated focal adhesion kinase (FAK) at the major activating tyrosine site (Y397) in epithelial ovarian cancer (EOC) cells and tumor-associated endothelial cells. FAK gene amplification as a mechanism for FAK overexpression and the effects of FAK tyrosine kinase inhibitor VS-6062 on tumor growth, metastasis, and angiogenesis were examined. FAK and phospho-FAKY397 were quantified in tumor (FAK-T; pFAK-T) and tumor-associated endothelial (FAK-endo; pFAK-endo) cell compartments of EOCs using immunostaining and qRT-PCR. Associations between expression levels and clinical variables were evaluated. Data from The Cancer Genome Atlas were used to correlate FAK gene copy number and expression levels in EOC specimens. The in vitro and in vivo effects of VS-6062 were assayed in preclinical models. FAK-T and pFAK-T overexpression was significantly associated with advanced stage disease and increased microvessel density (MVD). High MVD was observed in tumors with elevated endothelial cell FAK (59%) and pFAK (44%). Survival was adversely affected by FAK-T overexpression (3.03 vs 2.06 y, P = 0.004), pFAK-T (2.83 vs 1.78 y, P < 0.001), and pFAK-endo (2.33 vs 2.17 y, P = 0.005). FAK gene copy number was increased in 34% of tumors and correlated with expression levels (P < 0.001). VS-6062 significantly blocked EOC and endothelial cell migration as well as endothelial cell tube formation in vitro. VS-6062 reduced mean tumor weight by 56% (P = 0.005), tumor MVD by 40% (P = 0.0001), and extraovarian metastasis (P < 0.01) in orthotopic EOC mouse models. FAK may be a unique therapeutic target in EOC given the dual anti-angiogenic and anti-metastatic potential of FAK inhibitors.

A Comprehensive Comparison of Normalization Methods for Loading Control and Variance Stabilization of Reverse-Phase Protein Array Data

Abstract: Loading control (LC) and variance stabilization of reverse-phase protein array (RPPA) data have been challenging mainly due to the small number of proteins in an experiment and the lack of reliable inherent control markers. In this study, we compare eight different normalization methods for LC and variance stabilization. The invariant marker set concept was first applied to the normalization of high-throughput gene expression data. A set of “invariant” markers are selected to create a virtual reference sample. Then all the samples are normalized to the virtual reference. We propose a variant of this method in the context of RPPA data normalization and compare it with seven other normalization methods previously reported in the literature. The invariant marker set method performs well with respect to LC, variance stabilization and association with the immunohistochemistry/florescence in situ hybridization data for three key markers in breast tumor samples, while the other methods have inferior performance. The proposed method is a promising approach for improving the quality of RPPA data.

Abstract 4262: A pan-cancer proteomic analysis of The Cancer Genome Atlas (TCGA) project

Abstract: Protein levels and function are predicted poorly by genomic and transcriptomic analysis of patient tumors. Direct proteomic study can provide a wealth of information that complements those analysis in The Cancer Genome Atlas (TCGA) projects. We used reverse-phase protein arrays to analyze 3,467 patient samples from 11 TCGA “Pan-Cancer” diseases, using 181 high-quality antibodies that target 128 total proteins and 53 phospho-proteins. The resultant proteomic data were used for identifying commonalities, differences, emergent pathway properties, and novel network biology within and across tumor lineages. In general, tumor type and subtype were the dominant determinants of protein levels. However, we were able to identify several potentially targetable markers. E.g. luminal breast cancers demonstrated selective elevation of AR, BCL2, FASN, and pACC. SRC was activated in all but the hormone-responsive and bladder cancers, offering another potential therapeutic opportunity. Similarly, HER3 suggested itself as a potential target in renal cancer. EGFR activity, in general, paralleled SRC activity, but in GBM it was associated with NOTCH1 and HER3 activation, suggesting an opportunity for combination therapy. pSRC was highly expressed in a subset of head and neck tumors, suggesting that those may be more sensitive to EGFR targeting strategies. HER2 levels were elevated in a subset of endometrial, bladder, breast, and colorectal cancers. MYC was selectively amplified and expressed in high-grade serous ovarian cancers. We implemented a computational approach, MC, to decrease the effect of tissue-specific protein expression. MC allowed us to identify processes that drive cell behavior across tumor type and made it possible to find new therapeutic opportunities. We found 7 cross-tumor clusters, each driven by different markers and pathways. We found pan-cancer clusters with elevated HER2 and EGFR, elevated hormone signaling pathways, enriched MAPK and PI3K pathway activity, elevated EMT signatures, and cell cycle signatures. We also saw strong links between MYH11 and Rictor and between ETS1 and pPEA15 across tumor types. Those findings can provide useful clues for developing targeted, cross-tumor therapies. Pathway analysis of the data revealed several expected cross-tumor type associations, including pMEK with pERK, beta-catenin with E-cadherin and pPKCdelta with pPKCalpha and pPKCbeta. The findings support the ability of RPPA analysis to yield high-quality information from TCGA samples. A number of other links such as MYH11 with Rictor, cyclinB1 with FOXM1, and pACC with FASN were not expected and warrant further exploration, as does a negative link between p85 and claudin7 in lung squamous. Analysis of key nodes (e.g., CDK1) revealed other unexpected links to a wide range of protein pathways. Overall, those findings demonstrate the power of pan-cancer proteomic analysis, identifying several novel single-tumor and cross-tumor targets and pathways. Citation Format: Rehan Akbani, Kwok-Shing Ng, Henrica M. Werner, Fan Zhang, Zhenlin Ju, Wenbin Liu, Ji-Yeon Yang, Yiling Lu, John N. Weinstein, Gordon B. Mills. A pan-cancer proteomic analysis of The Cancer Genome Atlas (TCGA) project. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4262. doi:10.1158/1538-7445.AM2014-4262

Comprehensive molecular profiling of urothelial bladder cancer at the DNA, RNA, and protein levels: A TCGA project.

Abstract: 4509 Background: Urothelial carcinoma (UC) is a major cause of mortality with no approved molecularly targeted agents or good treatment options beyond cisplatin-based chemotherapy. Methods: For The Cancer Genome Atlas (TCGA), we profiled muscle-invasive UCs for mutations, DNA copy number variants (CNVs), mRNA and microRNA expression, protein expression and phosphorylation, DNA methylation, transcript splicing, gene fusion, viral integration, pathway perturbation, clinical correlates, and histopathology. The finding here are based on the first 131 tumors, but >250 more are being processed as of 1/2014. Results: Whole-exome sequencing revealed 29 recurrently mutated genes. Potential therapeutic targets included altered PIK3CA, ERBB2, FGFR3, TSC1, and ERBB3, plus mutated chromatin-regulating genes MLL, MLL2, MLL3, CREBBP, CHD7, SRCAP, ARID1A, KDM6A (UTX), and EP300. There were 27 focal CNVs, including CDKN2A deletion in 47%. Low-pass whole-genome sequencing identified 3 tumors with FGFR3-TACC3 fusions. Viral...