Search Results - EGA European Genome-Phenome Archive

Direct Detection of Early-stage Cancers Using Circulating Tumor DNA

Early detection and intervention are likely to be the most effective means for reducing morbidity and mortality of human cancer. However, development of methods for noninvasive detection of early-stage tumors has remained a challenge. We have developed an approach called targeted error correction sequencing (TEC-Seq) that allows ultrasensitive direct evaluation of sequence changes in circulating cell-free DNA using massively parallel sequencing. We have used this approach to examine 58 cancer-related genes encompassing 81 kb. Analysis of plasma from 44 healthy individuals identified genomic changes related to clonal hematopoiesis in 16% of asymptomatic individuals but no alterations in driver genes related to solid cancers. Evaluation of 200 patients with colorectal, breast, lung, or ovarian cancer detected somatic mutations in the plasma of 71, 59, 59, and 68%, respectively, of patients with stage I or II disease. Analyses of mutations in the circulation revealed high concordance with alterations in the tumors of these patients. In patients with resectable colorectal cancers, higher amounts of preoperative circulating tumor DNA were associated with disease recurrence and decreased overall survival. These analyses provide a broadly applicable approach for noninvasive detection of early-stage tumors that may be useful for screening and management of patients with cancer.

Study EGAS00001002577

DEPArray-based sorting of pure carcinoma and stromal populations from formalin-fixed paraffin-embedded (FFPE) tissues followed by shallow whole genome sequencing

To overcome the challenges of low DNA yields, degraded DNA by formalin fixation and diluted signal of genomic aberrations by non-carcinoma components in the heterogeneous FFPE samples, we isolated pure carcinoma and stromal cells using the DEPArray™ NxT system, a microchip-based digital sorter that allows isolation of pure, homogeneous subpopulations of cells from FFPE samples. We isolated pure carcinoma and stromal cell populations from 12 FFPE tissues, including tissues from 9 primary and metastatic breast cancer and 3 primary ovarian high-grade serous carcinomas. This was followed by downstream shallow whole genome sequencing (WGS) for copy number landscape profiling for 10 samples. Seven out of 10 samples (even some with low tumour content or of old age) produced good quality genomic data, detecting sCNA in all carcinoma population samples but not in the stromal populations.

Study EGAS50000001328

Single-cell RNA-seq data from metastatic ovarian cancer for quality control study

Quality control is a crucial preliminary step in any single-cell RNAseq experiment, where hard thresholds are commonly used. In order to develop a methodology for a more precise cell filtering in the early steps of a scRNAseq data analysis, we collected tissue samples before chemotherapy from 4 patients.

Study EGAS00001005066

The Breast and Prostate Cancer Cohort Consortium (BPC3) GWAS of Aggressive Prostate Cancer and ER- Breast Cancer

The Breast and Prostate Cancer Cohort Consortium (BPC3) was established in 2003 to pool data and biospecimens from nine large prospective cohorts to conduct research on gene-environment interactions in cancer etiology. The BPC3 initially focused on the association of >70 candidate genes in the Steroid Hormone Metabolism and IGF pathways with risk of breast and prostate cancer. The Consortium's work expanded in 2007 to include genome-wide association studies of estrogen receptor negative (ER-) breast cancer and aggressive prostate cancer. ER- breast cancers have specific epidemiologic characteristics and greater lethality, suggesting ER- breast cancer has a different etiology than ER+ breast cancer. Similarly, aggressive forms of prostate cancer, characterized by extraprostatic extension (Stage C/D) or high histologic grade (Gleason score 8+), differ epidemiologically from the vastly more common indolent forms of prostate cancer and are of the greatest clinical importance. By restricting cases to these specific subtypes, the BPC3 GWAS increased power to detect loci associated with ER- and aggressive prostate cancer (Kraft P and Haiman CA, Nature Genetics 2010 Oct;42:819-20, PMID: 20877320 ). The BPC3 GWAS includes the following cohorts: the American Cancer Society Cancer Prevention Study-II (CPS-II); the European Prospective Investigation of Cancer (EPIC); the Physician's Health Study (PHS); the Nurses' Health Studies I and II (NHS and NHSII); the Health Professionals Follow-up Study (HPFS); the Multiethnic Cohort (MEC); the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial; and the Alpha-Tocopherol, Beta-Carotene (ATBC) Study. For the GWAS of ER- cancer, the BPC3 was expanded to include the Polish Breast Cancer Study (PBCS), a population-based case-control study.

Study phs000812

The phase II Neo-Pembro trial: neoadjuvant pembrolizumab in stage IV high-grade serous ovarian cancer

While immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment, their efficacy in high-grade serous ovarian cancer (HGSOC) remains limited. Nevertheless, some patients achieve lasting responses, emphasizing the need to understand how the tumor microenvironment and molecular characteristics influence ICI response. We hypothesized higher efficacy of ICI when used in the neoadjuvant setting and preceded by induction chemotherapy. The phase 2 Neo-Pembro study (NCT03126812) included 33 untreated patients with stage IV HGSOC who were planned for 6 cycles of carboplatin-paclitaxel and interval cytoreductive surgery. Pembrolizumab (pembro) was added from cycle two and continued for one year. The primary objective was to assess intratumoral immune activation, through multiplexed immunofluorescence and immune-related gene expression. Our data provide evidence of immune activation, characterized by an increase in CD3+, CD8+, CD8+/FOXP3+ ratio, and TNF-α and interferon-γ signaling, and was most evident in major pathologic responders, which were 9/33 patients (27%, 95%CI 14-46) at time of surgery. Pathologic response was strongly associated with overall survival. At a median follow-up of 52.8 months, 8/9 major responders were alive, including 6 patients without recurrence, and 4 of 24 minor responders were alive, including one patient without recurrence. PD-L1 expression and homologous recombination deficiency were predictive of major response and may serve as potential biomarkers, warranting further exploration. In a post-hoc comparison, major responders treated with pembro had significantly better overall survival than major responders in a historic cohort treated without pembro. Our data indicate that immune activation was stronger in the subset of major pathologic responders and these patients may derive long-term survival benefits from the addition of neoadjuvant pembro.

Study EGAS50000000781

Molecular stratification of endometrioid ovarian carcinoma predicts clinical outcome

Endometrioid ovarian carcinoma (EnOC) is an under-investigated type of ovarian carcinoma. Here, we report the largest genomic study of EnOCs to date, performing whole exome sequencing of 112 cases following rigorous pathological assessment. High frequencies of mutation were detected in CTNNB1(43%), PIK3CA(43%), ARID1A(36%), PTEN(29%), TP53(26%) and SOX8(19%), a novel target of recurrent mutation in EnOC. POLE and mismatch repair protein-encoding genes were mutated at lower frequency (6%, 18%) with significant co-occurrence. A molecular taxonomy was constructed using a novel algorithm (PRISTINE), identifying clinically distinct EnOC subtypes: TP53m cases demonstrated greater genomic complexity, were frequently FIGO stage III/IV at diagnosis (48%) and incompletely debulked (44%), and demonstrated inferior survival; conversely, CTNNB1m cases demonstrated low complexity and excellent clinical outcome, were predominantly stage I/II at diagnosis (89%) and completely resected (87%). Tumour complexity provides further resolution within the TP53wt/CTNNB1wt group. Moreover, we identify the WNT, MAPK/RAS and PI3K pathways as good candidate targets for molecular therapeutics in EnOC.

Study EGAS00001004366

Single nucleus RNA sequencing of squamous cell carcinoma arising from mature teratoma of the ovary

Squamous cell carcinoma arising from mature teratoma is one of the rare ovarian cancers. Therefore, the detailed molecular background of this disease has not been elucidated. The purpose of this study is to investigate the single-cell transcriptional landscape of this disease.

Study JGAS000521

Beyond BRCA deficiency: Clinical and molecular predictors of survival in patients with BRCA-deficient tubo-ovarian high-grade serous carcinoma

Homologous recombination DNA repair deficient (HRD) tumors account for about 50% of tubo-ovarian high-grade serous carcinomas (HGSC) and are associated with a high response to platinum-based chemotherapy. However, a subset of patients with HRD tumors have unexpected resistance to chemotherapy and experience short survival. Our study compared BRCA-deficient and proficient HGSC among patients with short (<3 years, the lowest quartile of overall survival (OS)) versus longer-term (>3 year OS) to identify prognostic markers and potential therapeutic opportunities. Primary tumors from a cohort of patients with advanced-stage HGSC (n=154) enriched for those with HRD tumors and short survival (n=42) were analyzed using whole-genome sequencing, bulk RNA-sequencing, and DNA methylation profiling. A subset of HRD tumors (n=143) were characterized for immune cell densities by multiplex immunofluorescence. Clinicopathological features were assessed in 1,389 patients with HGSC, including 282 with pathogenic germline BRCA variants (gBRCApv). Findings were validated in two international HGSC cohorts: the Ovarian Tumor Tissue Analysis consortium (n=5,875) and Multisciplinary Ovarian Cancer Outcome Group (n=895). In gBRCApv-carriers, residual disease following surgical cytoreduction was not associated with shorter OS unlike in non-carriers where it was strongly associated. While most patients with gBRCApv had a more favorable OS compared to non-carriers, a survival advantage was not apparent in those with variants located outside of BRCA1 exon 10/23 and BRCA2 exon 11/27. Patient survival correlated with HRD score, such that those with a score ≥63 had significantly longer OS compared to those with HRD scores of 42-63 and <42. While higher HRD scores were associated with better survival outcomes, most gBRCApv carriers with a short survival had tumor HRD scores that exceeded the threshold typically considered predictive of a good response to carboplatin or PARP inhibitors. BRCA2-deficient HGSC with loss of the tumor suppressor NF1 was associated with exceptionally favorable outcome (median OS 17 years), whereas amplification of both PIK3CA and RAD21, was associated with poor outcome in BRCA2-deficient HGSC (median OS 2.9 years). The density of tumor-infiltrating CD8+ PD-1+ T cells was prognostic for OS in gBRCApv-carriers. In summary, rather than simply the presence or absence of a germline BRCA pathological variant influencing patient survival, the co-occurrence of specific somatic gene alterations, the extent of immune cell infiltration, the level of homologous recombination deficiency, and BRCA-variant location may modify clinical outcomes in patients with BRCA-deficient HGSC. Analysis of exceptional outcome patients, in this case gBRCApv-carriers with an atypically short survival, may identify determinants of outcome applicable to the wider HGSC patient population.

Study EGAS00001008059

Somatic mutations in endometriosis and normal uterine endometrium

To characterize the genomic features of endometriosis, we performed whole-exome sequencing for ovarian endometriotic epithelium samples obtained from subjects without concurrent gynecological cancers. Additionally, we analyzed histologically normal uterine endometrial epithelium samples obtained from subjects with benign gynecologic diseases. All the epithelium samples were isolated by laser microdissection from frozen sections.

Study EGAS00001003095

Epigenetic Control of Topoisomerase 1 by MacroH2A1.1

DNA transactions introduce torsional constraints that pose an inherent risk to genome integrity. While topoisomerase 1 (TOP1) activity is essential for removing DNA supercoiling, aberrant stabilization of TOP1:DNA cleavage complexes (TOP1ccs) can result in cytotoxic single-stranded DNA lesions (SSLs). What protects the genome from aberrant TOP1 activity remains unknown. Using a combination of CUT&RUN and TOP1 Covalent Adduct Detection (CAD) Seq in MDA-MB-231 breast cancer cells (American Type Culture Collection, ATCC), we identified chromatin context as an essential means to ensure TOP1cc resolution at TOP1 hot spots. Through its ability to bind poly(ADP-ribose) (PAR), a protein modification required for TOP1cc repair, the histone variant macroH2A1.1 establishes a TOP1-permissive chromatin environment, while the alternatively spliced macroH2A1.2 isoform is unable to bind PAR or protect from TOP1ccs. MacroH2A1 isoform-specific analyses were based on reconstitution of macroH2A1.1 knockout cells with wild-type or PAR binding-deficient FLAG-tagged macroH2A1.1 in human breast cancer cells. Mechanistically, we find that macroH2A1.1 facilitates the recruitment of the TOP1cc repair factor XRCC1 in response to both endogenous and drug-induced topological stress. Impaired macroH2A1.1 splicing, a frequent cancer feature, was predictive of increased sensitivity to TOP1 poisons in a pharmaco-genomic screen in breast cancer cells, and macroH2A1.1 inactivation mirrored this effect in breast and ovarian cancer cells. Consistent with this, low macroH2A1.1 expression correlated with improved survival in cancer patients treated with TOP1 inhibitors (TOP1i). We propose that macroH2A1 alternative splicing serves as an epigenetic modulator of TOP1-associated genome maintenance and a potential cancer vulnerability.

Study phs003729

3423 results for "ovarian cancer"

in 6.23 milliseconds.