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Payal Sipahimalani

University of North Carolina at Chapel Hill

Publishes on Cancer Genomics and Diagnostics, Occupational and environmental lung diseases, Medical Imaging and Pathology Studies. 146 papers and 87.8k citations.

146Publications
87.8kTotal Citations

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Comprehensive molecular characterization of gastric adenocarcinoma
Cited by 6.5kOpen Access

Gastric cancer is a leading cause of cancer deaths, but analysis of its molecular and clinical characteristics has been complicated by histological and aetiological heterogeneity. Here we describe a comprehensive molecular evaluation of 295 primary gastric adenocarcinomas as part of The Cancer Genome Atlas (TCGA) project. We propose a molecular classification dividing gastric cancer into four subtypes: tumours positive for Epstein–Barr virus, which display recurrent PIK3CA mutations, extreme DNA hypermethylation, and amplification of JAK2, CD274 (also known as PD-L1) and PDCD1LG2 (also known as PD-L2); microsatellite unstable tumours, which show elevated mutation rates, including mutations of genes encoding targetable oncogenic signalling proteins; genomically stable tumours, which are enriched for the diffuse histological variant and mutations of RHOA or fusions involving RHO-family GTPase-activating proteins; and tumours with chromosomal instability, which show marked aneuploidy and focal amplification of receptor tyrosine kinases. Identification of these subtypes provides a roadmap for patient stratification and trials of targeted therapies. The Cancer Genome Atlas reports on molecular evaluation of 295 primary gastric adenocarcinomas and proposes a new classification of gastric cancers into 4 subtypes, which should help with clinical assessment and trials of targeted therapies. This contribution from The Cancer Genome Atlas (TCGA) project describes the molecular evaluation of 295 primary gastric adenocarcinomas. Based on the results, the authors propose a novel classification separating gastric cancers into four subtypes according to: Epstein–Barr virus positive status, microsatellite instability, chromosomal instability or genomic stability. Given the histologic and etiologic heterogeneity of gastric cancer identification of these subtypes, using a schema that can readily be applied to patient samples should help with patient stratification and trials of targeted therapies.

LY-CoV1404 (bebtelovimab) potently neutralizes SARS-CoV-2 variants
Cited by 460Open Access

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-neutralizing monoclonal antibodies (mAbs) can reduce the risk of hospitalization from coronavirus disease 2019 (COVID-19) when administered early. However, SARS-CoV-2 variants of concern (VOCs) have negatively affected therapeutic use of some authorized mAbs. Using a high-throughput B cell screening pipeline, we isolated LY-CoV1404 (bebtelovimab), a highly potent SARS-CoV-2 spike glycoprotein receptor binding domain (RBD)-specific antibody. LY-CoV1404 potently neutralizes authentic SARS-CoV-2, B.1.1.7, B.1.351, and B.1.617.2. In pseudovirus neutralization studies, LY-CoV1404 potently neutralizes variants, including B.1.1.7, B.1.351, B.1.617.2, B.1.427/B.1.429, P.1, B.1.526, B.1.1.529, and the BA.2 subvariant. Structural analysis reveals that the contact residues of the LY-CoV1404 epitope are highly conserved, except for N439 and N501. The binding and neutralizing activity of LY-CoV1404 is unaffected by the most common mutations at these positions (N439K and N501Y). The broad and potent neutralization activity and the relatively conserved epitope suggest that LY-CoV1404 has the potential to be an effective therapeutic agent to treat all known variants.

Integrated genomic characterization of endometrial carcinoma
Gad Getz, Stacey Gabriel, Kristian Cibulskis et al.|Carolina Digital Repository (University of North Carolina at Chapel Hill)|2013
Cited by 414Open Access

We performed an integrated genomic, transcriptomic and proteomic characterization of 373 endometrial carcinomas using array-and sequencing-based technologies. Uterine serous tumours and ∼25% of high-grade endometrioid tumours had extensive copy number alterations, few DNA methylation changes, low oestrogen receptor/progesterone receptor levels, and frequent TP53 mutations. Most endometrioid tumours had few copy number alterations or TP53 mutations, but frequent mutations in PTEN, CTNNB1, PIK3CA, ARID1A and KRAS and novel mutations in the SWI/SNF chromatin remodelling complex gene ARID5B. A subset of endometrioid tumours that we identified had a markedly increased transversion mutation frequency and newly identified hotspot mutations in POLE. Our results classified endometrial cancers into four categories: POLE ultramutated, microsatellite instability hypermutated, copy-number low, and copy-number high. Uterine serous carcinomas share genomic features with ovarian serous and basal-like breast carcinomas. We demonstrated that the genomic features of endometrial carcinomas permit a reclassification that may affect post-surgical adjuvant treatment for women with aggressive tumours. © 2013 Macmillan Publishers Limited. All rights reserved.

Characterization of HPV and host genome interactions in primary head and neck cancers
Michael Parfenov, Chandra Sekhar Pedamallu, Nils Gehlenborg et al.|Proceedings of the National Academy of Sciences|2014
Cited by 394Open Access

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.