scholarly journals MEDALT: single-cell copy number lineage tracing enabling gene discovery

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Fang Wang ◽  
Qihan Wang ◽  
Vakul Mohanty ◽  
Shaoheng Liang ◽  
Jinzhuang Dou ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Single Cell ◽  
Copy Number ◽  
Speciation Analysis ◽  
Population Based ◽  
Lineage Tracing ◽  
Breast Cancer Patients ◽  
Lineage Tree ◽  
History Of ◽  
A Cell

AbstractWe present a Minimal Event Distance Aneuploidy Lineage Tree (MEDALT) algorithm that infers the evolution history of a cell population based on single-cell copy number (SCCN) profiles, and a statistical routine named lineage speciation analysis (LSA), whichty facilitates discovery of fitness-associated alterations and genes from SCCN lineage trees. MEDALT appears more accurate than phylogenetics approaches in reconstructing copy number lineage. From data from 20 triple-negative breast cancer patients, our approaches effectively prioritize genes that are essential for breast cancer cell fitness and predict patient survival, including those implicating convergent evolution.The source code of our study is available at https://github.com/KChen-lab/MEDALT.

scholarly journals Single-cell copy number lineage tracing enabling gene discovery

2020 ◽  
Author(s):  
Fang Wang ◽  
Qihan Wang ◽  
Vakul Mohanty ◽  
Shaoheng Liang ◽  
Jinzhuang Dou ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Single Cell ◽  
Cancer Patients ◽  
Copy Number ◽  
Speciation Analysis ◽  
Tissue Level ◽  
Lineage Tracing ◽  
Evolutionary Stage ◽  
Breast Cancer Patients ◽  
Sequencing Data

AbstractAneuploidy plays critical roles in genome evolution.Alleles, whose dosages affect the fitness of an ancestor, will have altered frequencies in the descendant populations upon perturbation.Single-cell sequencing enables comprehensive genome-wide copy number profiling of thousands of cells at various evolutionary stage and lineage. That makes it possible to discover dosage effects invisible at tissue level, provided that the cell lineages can be accurately reconstructed.Here, we present a Minimal Event Distance Aneuploidy Lineage Tree (MEDALT) algorithm that infers the evolution history of a cell population based on single-cell copy number (SCCN) profiles. We also present a statistical routine named lineage speciation analysis (LSA), which facilitates discovery of fitness-associated alterations and genes from SCCN lineage trees.We assessed our approaches using a variety of single-cell datasets. Overall, MEDALT appeared more accurate than phylogenetics approaches in reconstructing copy number lineage. From the single-cell DNA-sequencing data of 20 triple-negative breast cancer patients, our approaches effectively prioritized genes that are essential for breast cancer cell fitness and are predictive of patient survival, including those implicating convergent evolution. Similar benefits were observed when applying our approaches on single-cell RNA sequencing data obtained from cancer patients.The source code of our study is available at https://github.com/KChen-lab/MEDALT.

Risk of ovarian cancer in breast-cancer patients with a family history of breast or ovarian cancer: a population-based cohort study

The Lancet ◽  
2002 ◽  
Vol 360 (9337) ◽  
pp. 891-894 ◽  
Author(s):  
Kjell Bergfeldt ◽  
Bosse Rydh ◽  
Fredrik Granath ◽  
Henrik Grönberg ◽  
Lukman Thalib ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Ovarian Cancer ◽  
Cohort Study ◽  
Family History ◽  
Cancer Patients ◽  
Population Based ◽  
Breast Cancer Patients ◽  
History Of

scholarly journals SCuPhr: A Probabilistic Framework for Cell Lineage Tree Reconstruction

2018 ◽  
Author(s):  
Hazal Koptagel ◽  
Seong-Hwan Jun ◽  
Jens Lagergren
Keyword(s):  
Dna Sequencing ◽  
Single Cell ◽  
Copy Number ◽  
Cell Lineage ◽  
Lineage Tracing ◽  
The Other ◽  
Sequencing Data ◽  
Data Set ◽  
Detailed Model ◽  
Lineage Tree

AbstractReconstruction of cell lineage trees from single-cell DNA sequencing data, has the potential to become a fundamental tool in study of development of disease, in particular cancer. For cells without copy number alterations that has not been exposed to specific marking techniques, that is normal cells, lineage tracing is naturally based on somatic point mutations. Current single cell sequencing techniques applicable to such cells require an amplification step, which introduces errors, and still often suffer from so-called allelic dropout. We present a detailed model of current technologies for the purpose of estimating the distance between cells without copy number changes, based on single-cell DNA sequencing data. The model is well suited for full Bayesian analysis by introducing prior probabilities for key parameters as well as maximum a posteriori estimation using expectation maximization algorithm. Our model outputs distance between two cells, simultaneously taking all the other cells into account. In particular, the model contains variables associated with pairs of loci, of which one is homozygous and the other heterozygous, and has the capacity to perform Bayesian probabilistic read phasing. By applying a fast distance based method, such as FNJ, to the estimated distance, a cell lineage tree can be obtained. In contrast to MCMC based methods, FNJ can easily handle data sets with tens of thousands of taxa. The high accuracy of the so obtained method, called SCuPhr, is shown in studies of several synthetic data set.

Neoadjuvant Chemotherapy Induces the Appearance of New Copy Number Aberrations in Breast Tumor and is Associated with Metastasis

2020 ◽  
Vol 20 (9) ◽  
pp. 681-688
Author(s):  
Nikolai V. Litviakov ◽  
Marina K. Ibragimova ◽  
Matvey M. Tsyganov ◽  
Artem V. Doroshenko ◽  
Eugeniy Y. Garbukov ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Neoadjuvant Chemotherapy ◽  
Copy Number ◽  
Breast Cancer Patients ◽  
Free Survival ◽  
Luminal B ◽  
Cell Clones ◽  
Genetic Landscape ◽  
Intelligent Approach

Background: In this study, we examined the CNA-genetic landscape (CNA – copy number aberration) of breast cancer prior to and following neoadjuvant chemotherapy (NAC) and correlated changes in the tumor landscape with chemotherapy efficiency as well as metastasis-free survival. Objective: Breast cancer patients (n = 30) with luminal B molecular subtypes were treated with anthracycline- based therapy. Methods: To study CNAs in breast tumors, microarray analysis was performed. Results: Three effects of NAC on tumor CNA landscape were identified: 1 – the number of CNA-bearing tumor clones decreased following NAC; 2 – there were no alterations in the number of CNA-containing clones after NAC; 3 – the treatment with NAC increased the number of CNA-bearing clones (new clones appeared). All NAC-treated patients who had new tumor clones with amplification (20%) had a 100% likelihood of metastasis formation. In these cases, NAC contributed to the emergence of potential metastatic clones. Our study identified the following loci – 5p, 6p, 7q, 8q, 9p, 10p, 10q22.1, 13q, 16p, 18Chr and 19p – that were amplified during the treatment with NAC and may be the markers of potential metastatic clones. In other patients who showed total or partial elimination of CNA-bearing cell clones, no new amplification clones were observed after NAC, and no evidence of metastases was found with follow-up for 5 years (р = 0.00000). Conclusion: Our data suggest that the main therapeutic result from NAC is the elimination of potential metastatic clones present in the tumor before treatment. The results showed the necessity of an intelligent approach to NAC to avoid metastasis stimulation.

Antiestrogen use in breast cancer patients reduces the risk of subsequent lung cancer: A population-based study

2017 ◽  
Vol 48 ◽  
pp. 22-28 ◽  
Author(s):  
Sung-Chao Chu ◽  
Chia-Jung Hsieh ◽  
Tso-Fu Wang ◽  
Mun-Kun Hong ◽  
Tang-Yuan Chu
Keyword(s):  
Breast Cancer ◽  
Lung Cancer ◽  
Cancer Patients ◽  
Population Based ◽  
Breast Cancer Patients ◽  
Population Based Study

scholarly journals Single Cell Genetic Profiling of Tumors of Breast Cancer Patients Aged 50 Years and Older Reveals Enormous Intratumor Heterogeneity Independent of Individual Prognosis

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3366
Author(s):  
Anna-Sophie Liegmann ◽  
Kerstin Heselmeyer-Haddad ◽  
Annette Lischka ◽  
Daniela Hirsch ◽  
Wei-Dong Chen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Copy Number ◽  
Genome Instability ◽  
Single Cells ◽  
Gene Mutations ◽  
Intratumor Heterogeneity ◽  
Breast Cancer Patients ◽  
Luminal A ◽  
Pik3ca Mutations

Purpose: Older breast cancer patients are underrepresented in cancer research even though the majority (81.4%) of women dying of breast cancer are 55 years and older. Here we study a common phenomenon observed in breast cancer which is a large inter- and intratumor heterogeneity; this poses a tremendous clinical challenge, for example with respect to treatment stratification. To further elucidate genomic instability and tumor heterogeneity in older patients, we analyzed the genetic aberration profiles of 39 breast cancer patients aged 50 years and older (median 67 years) with either short (median 2.4 years) or long survival (median 19 years). The analysis was based on copy number enumeration of eight breast cancer-associated genes using multiplex interphase fluorescence in situ hybridization (miFISH) of single cells, and by targeted next-generation sequencing of 563 cancer-related genes. Results: We detected enormous inter- and intratumor heterogeneity, yet maintenance of common cancer gene mutations and breast cancer specific chromosomal gains and losses. The gain of COX2 was most common (72%), followed by MYC (69%); losses were most prevalent for CDH1 (74%) and TP53 (69%). The degree of intratumor heterogeneity did not correlate with disease outcome. Comparing the miFISH results of diploid with aneuploid tumor samples significant differences were found: aneuploid tumors showed significantly higher average signal numbers, copy number alterations (CNAs) and instability indices. Mutations in PIKC3A were mostly restricted to luminal A tumors. Furthermore, a significant co-occurrence of CNAs of DBC2/MYC, HER2/DBC2 and HER2/TP53 and mutual exclusivity of CNAs of HER2 and PIK3CA mutations and CNAs of CCND1 and PIK3CA mutations were revealed. Conclusion: Our results provide a comprehensive picture of genome instability profiles with a large variety of inter- and intratumor heterogeneity in breast cancer patients aged 50 years and older. In most cases, the distribution of chromosomal aneuploidies was consistent with previous results; however, striking exceptions, such as tumors driven by exclusive loss of chromosomes, were identified.

scholarly journals Characterisation of protein-truncating and missense variants in PALB2 in 15 768 women from Malaysia and Singapore

2021 ◽  
pp. jmedgenet-2020-107471
Author(s):  
Pei Sze Ng ◽  
Rick ACM Boonen ◽  
Eldarina Wijaya ◽  
Chan Eng Chong ◽  
Milan Sharma ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Rare Variants ◽  
Embryonic Stem ◽  
Mouse Embryonic Stem Cell ◽  
Population Based ◽  
Breast Cancer Patients ◽  
Dna Double Strand Breaks ◽  
Functional Impact ◽  
Missense Variants ◽  
Increased Risk

BackgroundRare protein-truncating variants (PTVs) in partner and localiser of BRCA2 (PALB2) confer increased risk to breast cancer, but relatively few studies have reported the prevalence in South-East Asian populations. Here, we describe the prevalence of rare variants in PALB2 in a population-based study of 7840 breast cancer cases and 7928 healthy Chinese, Malay and Indian women from Malaysia and Singapore, and describe the functional impact of germline missense variants identified in this population.MethodsMutation testing was performed on germline DNA (n=15 768) using targeted sequencing panels. The functional impact of missense variants was tested in mouse embryonic stem cell based functional assays.ResultsPTVs in PALB2 were found in 0.73% of breast cancer patients and 0.14% of healthy individuals (OR=5.44; 95% CI 2.85 to 10.39, p<0.0001). In contrast, rare missense variants in PALB2 were not associated with increased risk of breast cancer. Whereas PTVs were associated with later stage of presentation and higher-grade tumours, no significant association was observed with missense variants in PALB2. However, two novel rare missense variants (p.L1027R and p.G1043V) produced unstable proteins and resulted in a decrease in homologous recombination-mediated repair of DNA double-strand breaks.ConclusionDespite genetic and lifestyle differences between Asian and other populations, the population prevalence of PALB2 PTVs and associated relative risk of breast cancer, are similar to those reported in European populations.

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