Project description:Full-term pregnancy (FTP) at an early age confers long-term protection against breast cancer, in this study, we evaluated gene expression changes induced by parity in the breast of premenopausal women. Gene expression profiling of normal breast tissue from 30 nulliparous (NP) and 79 parous (P) premenopausal volunteers were performed using Affymetrix microarrays. In addition to a discovery/validation analysis, we conducted analysis of gene expression differences in P vs. NP women as a function of time since last FTP.
Project description:BACKGROUND:Full-term pregnancy (FTP) at an early age confers long-term protection against breast cancer. Previously, we reported that a FTP imprints a specific gene expression profile in the breast of postmenopausal women. Herein, we evaluated gene expression changes induced by parity in the breast of premenopausal women. METHODS:Gene expression profiling of normal breast tissue from 30 nulliparous (NP) and 79 parous (P) premenopausal volunteers was performed using Affymetrix microarrays. In addition to a discovery/validation analysis, we conducted an analysis of gene expression differences in P vs. NP women as a function of time since last FTP. Finally, a laser capture microdissection substudy was performed to compare the gene expression profile in the whole breast biopsy with that in the epithelial and stromal tissues. RESULTS:Discovery/validation analysis identified 43 differentially expressed genes in P vs. NP breast. Analysis of expression as a function of time since FTP revealed 286 differentially expressed genes (238 up- and 48 downregulated) comparing all P vs. all NP, and/or P women whose last FTP was less than 5 years before biopsy vs. all NP women. The upregulated genes showed three expression patterns: (1) transient: genes upregulated after FTP but whose expression levels returned to NP levels. These genes were mainly related to immune response, specifically activation of T cells. (2) Long-term changing: genes upregulated following FTP, whose expression levels decreased with increasing time since FTP but did not return to NP levels. These were related to immune response and development. (3) Long-term constant: genes that remained upregulated in parous compared to nulliparous breast, independently of time since FTP. These were mainly involved in development/cell differentiation processes, and also chromatin remodeling. Lastly, we found that the gene expression in whole tissue was a weighted average of the expression in epithelial and stromal tissues. CONCLUSIONS:Genes transiently activated by FTP may have a role in protecting the mammary gland against neoplastically transformed cells through activation of T cells. Furthermore, chromatin remodeling and cell differentiation, represented by the genes that are maintained upregulated long after the FTP, may be responsible for the lasting preventive effect against breast cancer.
Project description:The aim of the experiment was to identify the change of gene expression in human ovaries between premenopausal women and postmenopausal women based on DNA microarrays analysis. 8 human ovary samples were assembled from premenopausal women (n=4) and from postmenopausal women (n=4), respectively. The active transcription profiles of human ovaries were identified through DNA microarrays. Differentially expressed genes (DEGs) were identified as at least two-fold change with statistical significance. Enrichment of functions and signaling pathways analysis were performed based on Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes database.
Project description:Case-control study for the analysis of the gene expression profile of epithelial cells microdissected from normal breast tissues obtained from 17 parous and 7 nulliparous women free of breast pathology (controls), and 39 parous and 8 nulliparous women with history of breast cancer (cases). Keywords: genetic modifications
Project description:Progesterone receptor antagonism is gaining attention due to progesterone's recognized role as a major mitogen in breast tissue. Limited but promising data suggest the potential efficacy of antiprogestins in breast cancer prevention. The present study presents secondary outcomes from a randomized controlled trial examining changes in breast mRNA expression following mifepristone treatment in healthy women. We analyzed 32 paired breast biopsies from 16 healthy premenopausal women at baseline and after two months of mifepristone treatment. In total, twenty-seven differentially expressed genes were identified, with enriched biological functions related to extracellular matrix remodeling. Notably, the altered gene signature induced by mifepristone in vivo was rather similar to the in vitro signature. Furthermore, this expression gene signature was associated with breast carcinogenesis and significantly correlated with progesterone receptor expression status in breast cancer, as validated in The Cancer Genome Atlas dataset using the R2 platform. The present study is the first to explore the breast transciptome following mifepristone treatment in healthy breast tissue in vivo, enhancing the understanding of progesterone receptor modulator and its potential protective effects against breast cancer by investigating its action in healthy breast tissue.
Project description:We assessed the effect of dietary glycemic load on miRNA expression in a sample of healthy, premenopausal women participating in a 12 month intervention designed to lower dietary glycemic load.
Project description:RNA-sequencing was performed on patient mammary epithelial cell subsets from premenopausal and postmenopausal women undergoing breast reduction surgeries to interrogate transcriptional changes in postmenopausal cells.
Project description:Case-control study for the analysis of the gene expression profile of epithelial cells microdissected from normal breast tissues obtained from 17 parous and 7 nulliparous women free of breast pathology (controls), and 39 parous and 8 nulliparous women with history of breast cancer (cases). Keywords: genetic modifications Four-condition experiment: nulliparous case, nulliparous control, parous case and parous control labeled with Cy5 and Universal human reference used as a common reference labeled with Cy3. Moderated t statistic was used as the basic statistic for significance analysis; it was computed for each probe and for each contrast. False discovery rate was controlled using the Benjamini and Hochberg. All genes with P value below a threshold of 0.05 were selected as differentially expressed, maintaining the proportion of false discoveries in the selected group below the threshold value, in this case 5%. Breast 11 parous control HuII, Breast 28 parous case HuII, and Breast 62 nulliparous control HuIII excluded: raw data is missing
Project description:We assessed the effect of dietary glycemic load on miRNA expression in a sample of healthy, premenopausal women participating in a 12 month intervention designed to lower dietary glycemic load. Comparing post-intervention to baseline miRNA expression data of 14 participants receiving the active intervention.
Project description:For premenopausal women with primary ER+ breast cancer, oophorectomy (OvX) is an evidence-based cost-effective option and is standard treatment in many countries. However, there is virtually no data describing the effects of OvX on breast tumour biology. We therefore characterized the endocrine and genome-wide transcriptional impact of OvX in 56 premenopausal women with ER+ breast cancer for two weeks prior to mastectomy. Plasma estradiol concentrations decreased from 421±305 to 24.1±24.5 pmol/l (mean±sd) 24 hours after OvX and to 8.8±7.3pmol/l two weeks later at mastectomy. Ki67 decreased in 33/36 (91.7%) tumours. The expression of 655 genes changed significantly (FDR<1%) with an absolute mean fold-change (FC) ≥1.25 (257 up, 398 down). Archetypal oestrogen-regulated genes, proliferation-associated genes and putative progesterone-regulated genes were strongly down-regulated. The gene expression changes did not differ according to HER2 status and correlated strongly with those after aromatase inhibitor (AI) treatment in 81 postmenopausal women. However, after OvX the mean FC was significantly higher compared to AI. In conclusion, changes in tumoural gene expression after OvX were largely similar but of a greater magnitude to those observed after AI in postmenopausal patients but OvX appeared to have a greater effect on progesterone-regulated genes than AI.