Similar Datasets
Project description:Epigenetic mechanisms such as DNA methylation are important regulators of gene expression and are frequently dysregulated early in breast carcinogenesis. The relationship between DNA methylation aberrations in normal breast tissue and breast cancer risk remains unclear. Disease-free breast tissue cores donated by high-risk (Tyrer-Cuzick lifetime risk ≥20%) and 78 average-risk women were obtained from the Susan G. Komen Tissue Bank and processed for whole methylome and whole transcriptome profiling. We identified 1355 CpGs that were differentially methylated between high- and average-risk breast tissues (ΔZ>0.5, FDR<0.05). Hypomethylated CpGs were overrepresented in high-risk tissue and were found predominantly (68%) in non-coding regions. Hypermethylated CpG sites were found equally in the gene body and non-coding regions. Transcriptomic analysis identified 67 differentially expressed genes (fold change≥2, FDR<0.05, 17 down 50 up), involved in chemokines signaling, metabolism and estrogen biosynthesis. Methylation-expression correlations revealed 6 epigenetically regulated genes in high-risk breast. This is the first gene expression/DNA methylation analysis of normal breasts from women at either high or average risk of breast cancer. Our discovery of epigenetically regulated genes associated with breast cancer risk using a unique resource of normal breast samples opens the doors to a deeper understanding of the process of cancer initiation and provides an opportunity to mechanistically dissect breast cancer susceptibility and risk-associated molecular alterations.
2021-09-30 | GSE164641 | GEO
Project description:Epigenetic mechanisms such as DNA methylation are important regulators of gene expression and are frequently dysregulated early in breast carcinogenesis. The relationship between DNA methylation aberrations in normal breast tissue and breast cancer risk remains unclear. Disease-free breast tissue cores donated by high-risk (Tyrer-Cuzick lifetime risk ≥20%) and 78 average-risk women were obtained from the Susan G. Komen Tissue Bank and processed for whole methylome and whole transcriptome profiling. We identified 1355 CpGs that were differentially methylated between high- and average-risk breast tissues (ΔZ>0.5, FDR<0.05). Hypomethylated CpGs were overrepresented in high-risk tissue and were found predominantly (68%) in non-coding regions. Hypermethylated CpG sites were found equally in the gene body and non-coding regions. Transcriptomic analysis identified 67 differentially expressed genes (fold change≥2, FDR<0.05, 17 down 50 up), involved in chemokines signaling, metabolism and estrogen biosynthesis. Methylation-expression correlations revealed 6 epigenetically regulated genes in high-risk breast. This is the first gene expression/DNA methylation analysis of normal breasts from women at either high or average risk of breast cancer. Our discovery of epigenetically regulated genes associated with breast cancer risk using a unique resource of normal breast samples opens the doors to a deeper understanding of the process of cancer initiation and provides an opportunity to mechanistically dissect breast cancer susceptibility and risk-associated molecular alterations.
2021-09-30 | GSE164640 | GEO
Project description:Transcriptome profiling of the normal breast of women at either high- or average risk for breast cancer
| PRJNA691572 | ENA
Project description:Transcriptome profiling of the normal breast of women at either high- or average risk for breast cancer [methyl-capture]
| PRJNA691576 | ENA
Project description:Transcriptome profiling of the normal breast of women at either high- or average risk for breast cancer [RNA-Seq]
| PRJNA691577 | ENA
Project description:Sporadic breast cancer develops through the accumulation of molecular abnormalities in normal breast tissue, resulting from exposure to estrogens and other carcinogens beginning at adolescence and continuing throughout life. These molecular changes may take a variety of forms, including numerical and structural chromosomal abnormalities, epigenetic changes, and gene expression alterations. To characterize these abnormalities, a review of the literature has been conducted to define the molecular changes in each of the above major genomic categories in normal breast tissue considered to be either at normal risk or at high risk for sporadic breast cancer. This review indicates that normal risk breast tissues (such as reduction mammoplasty) contain evidence of early breast carcinogenesis including loss of heterozygosity, DNA methylation of tumor suppressor and other genes, and telomere shortening. In normal tissues at high risk for breast cancer (such as normal breast tissue adjacent to breast cancer or the contralateral breast), these changes persist, and are increased and accompanied by aneuploidy, increased genomic instability, a wide range of gene expression differences, development of large cancerized fields, and increased proliferation. These changes are consistent with early and long-standing exposure to carcinogens, especially estrogens. A model for the breast carcinogenic pathway in normal risk and high-risk breast tissues is proposed. These findings should clarify our understanding of breast carcinogenesis in normal breast tissue and promote development of improved methods for risk assessment and breast cancer prevention in women.
| S-EPMC4990153 | biostudies-literature
Project description:Breast cancer develops through the accumulation of genomic changes in the ductal epithelia cells of normal breast tissue. A determination of whether gene expression changes in ductal cells is associated with an increased risk for breast cancer is needed. We sought to determine if the global gene expression profiles of ductal cells of women at high risk for breast cancer or with cytologic ductal epithelial atypia differed from those of women at normal risk or without cytologic atypia. We used microarrays to detail the gene expression profile of breast ductal cells associated with normal risk or high risk for sporadic breast cancer and with or without cytologic epithelial atypia. We did not identify any separation of the sample groups (normal risk vs high-risk, or atypia vs nonatypia) according to expression of subgroups of genes.
2020-07-05 | GSE153796 | GEO
Project description:IMPORTANCE:Breast cancer is a leading cause of premature mortality among US women. Early detection has been shown to be associated with reduced breast cancer morbidity and mortality. OBJECTIVE:To update the American Cancer Society (ACS) 2003 breast cancer screening guideline for women at average risk for breast cancer. PROCESS:The ACS commissioned a systematic evidence review of the breast cancer screening literature to inform the update and a supplemental analysis of mammography registry data to address questions related to the screening interval. Formulation of recommendations was based on the quality of the evidence and judgment (incorporating values and preferences) about the balance of benefits and harms. EVIDENCE SYNTHESIS:Screening mammography in women aged 40 to 69 years is associated with a reduction in breast cancer deaths across a range of study designs, and inferential evidence supports breast cancer screening for women 70 years and older who are in good health. Estimates of the cumulative lifetime risk of false-positive examination results are greater if screening begins at younger ages because of the greater number of mammograms, as well as the higher recall rate in younger women. The quality of the evidence for overdiagnosis is not sufficient to estimate a lifetime risk with confidence. Analysis examining the screening interval demonstrates more favorable tumor characteristics when premenopausal women are screened annually vs biennially. Evidence does not support routine clinical breast examination as a screening method for women at average risk. RECOMMENDATIONS:The ACS recommends that women with an average risk of breast cancer should undergo regular screening mammography starting at age 45 years (strong recommendation). Women aged 45 to 54 years should be screened annually (qualified recommendation). Women 55 years and older should transition to biennial screening or have the opportunity to continue screening annually (qualified recommendation). Women should have the opportunity to begin annual screening between the ages of 40 and 44 years (qualified recommendation). Women should continue screening mammography as long as their overall health is good and they have a life expectancy of 10 years or longer (qualified recommendation). The ACS does not recommend clinical breast examination for breast cancer screening among average-risk women at any age (qualified recommendation). CONCLUSIONS AND RELEVANCE:These updated ACS guidelines provide evidence-based recommendations for breast cancer screening for women at average risk of breast cancer. These recommendations should be considered by physicians and women in discussions about breast cancer screening.
| S-EPMC4831582 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below. Gene expression profiling of continuous or intermittent energy restriction in women at increased risk of breast cancer
2016-07-13 | GSE66162 | GEO
Project description:Circulating tumor cells (CTCs) have been shown to predict reduced survival outcomes in metastatic breast cancer. CTCs were analyzed in 2026 patients with early breast cancer before adjuvant chemotherapy and in 1492 patients after chemotherapy using the CellSearch System. After immuno-magnetic enrichment for cells expressing the epithelial-cell adhesion molecule, CTCs were defined as nucleated cells expressing cytokeratin and lacking CD45. The patients were followed for a median of 35 months (range = 0-54). Kaplan-Meier analyses and the log-rank test were used for survival analyses. All statistical tests were two-sided. Before chemotherapy, CTCs were detected in 21.5% of patients (n = 435 of 2026), with 19.6% (n = 136 of 692) of node-negative and 22.4% (n = 299 of 1334) of node-positive patients showing CTCs (P < .001). No association was found with tumor size, grading, or hormone receptor status. After chemotherapy, 22.1% of patients (n = 330 of 1493) were CTC positive. The presence of CTCs was associated with poor disease-free survival (DFS; P < .0001), distant DFS (P < .001), breast cancer-specific survival (P = .008), and overall survival (OS; P = .0002). CTCs were confirmed as independent prognostic markers in multivariable analysis for DFS (hazard ratio [HR] = 2.11; 95% confidence interval [CI] = 1.49 to 2.99; P < .0001) and OS (HR = 2.18; 95% CI = 1.32 to 3.59; P = .002). The prognosis was worst in patients with at least five CTCs per 30 mL blood (DFS: HR = 4.51, 95% CI = 2.59 to 7.86; OS: HR = 3.60, 95% CI = 1.56 to 8.45). The presence of persisting CTCs after chemotherapy showed a negative influence on DFS (HR = 1.12; 95% CI = 1.02 to 1.25; P = .02) and on OS (HR = 1.16; 95% CI = 0.99 to 1.37; P = .06) CONCLUSIONS: These results suggest the independent prognostic relevance of CTCs both before and after adjuvant chemotherapy in a large prospective trial of patients with primary breast cancer.
| S-EPMC4112925 | biostudies-literature