Unknown,Transcriptomics,Genomics,Proteomics

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Identification of novel biomarkers associated with poor patient outcome in invasive breast carcinoma

ABSTRACT: Breast carcinoma (BC) is the leading cause of death in women worldwide, making up 23% of all cancers in women, with 1.38 million new cases worldwide annually and responsible for 460,000 deaths. Despite the significant advances in the identification of molecular markers and different modalities of treatment in primary BC, the ability to predict the metastatic behavior in breast cancer is still limited. The purpose of this study was to help identify novel molecular markers associated with clinical outcome in a cohort of Brazilian BC patients. We generated global gene expression profiles from 24 patients with invasive ductal BC followed for â¥ 5-years, including 15 samples from patients classified as presenting good prognosis based on traditional markers and clinical criteria and 9 patients that developed metastasis. We identified a set of 58 differentially expressed genes (p â¤0.01) between groups of patients with good and poor prognosis. Up-regulation of B3GNT7, PPM1D, TNKS2, PHB and GTSE1 in patients with poor prognosis was confirmed by quantitative RT-PCR in an independent sample set from patients with BC (47 with good prognosis and 8 that presented metastasis). Expression of BAD protein was investigated by immunohistochemistry in 1276 BC samples and confirmed the reduced expression levels in metastatic cases observed in the oligoarray data. These findings point to novel prognostic markers that can distinguish breast carcinoma samples according to clinical course and progression of the disease. Global expression profiles from 38 ductal breast tumor patient samples were used to search for molecular signatures correlated with current prognostic markers. A subset of 24 cases comprising 15 patients that remained free of disease after surgery and 9 patients that developed metastasis was used to identify candidate biomarkers associated with metastatic progression. Candidates were subsequently validated in additional independent samples by RT-qPCR or immunohistochemistry.

ORGANISM(S): Homo sapiens

SUBMITTER: Eduardo Reis

PROVIDER: E-GEOD-73383 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Introduction: MicroRNAs (miRNAs) are small, non-coding RNA molecules involved in post-transcriptional gene regulation and have recently been shown to play a role in cancer metastasis. In solid tumors, especially breast cancer, alterations in miRNA expression contribute to cancer pathogenesis, including metastasis. Considering the emerging role of miRNAs in metastasis, the identification of predictive markers is necessary to further understanding of stage-specific breast cancer development. This is a retrospective analysis that aimed to identify molecular biomarkers related to distant breast cancer metastasis development. Methods: A retrospective case cohort study was performed in 64 breast cancer patients treated during the period from 1998-2001. The case group (n=29) consisted of patients with a poor prognosis who presented with breast cancer recurrence or metastasis during follow up. The control group (n=35) consisted of a random sample of patients with a good prognosis who did not develop breast cancer recurrence or metastasis. These patient groups were stratified according to TNM clinical stage (CS) I, II and III, and the main clinical features of the patients were homogeneous. miRNA profiling was performed using formalin-fixed, paraffin-embedded tumors. Biomarkers related to metastatic potential were identified independent of clinical stage, and a cutoff point was selected based on the optimal sensitivity and specificity (ROC curve). Finally, a hazard risk analysis of these biomarkers was performed to evaluate their relation to metastatic potential. Results: miRNA expression profiling identified several miRNAs that were either specific and shared across all clinical stages (p?0.05). Among these, we identified miRNAs previously associated with cell motility (let-7 family), cell proliferation and invasion (hsa-miR-16 and has-miR-205) and distant metastasis (hsa-miR-21). In addition, hsa-miR-494 and hsa-miR-21 were up-regulated in metastatic cases of CSI and II. Furthermore, the combination of the 3 miRNAs identified for CSII (hsa-miR-494, hsa-miR-183 and hsa-miR-21) was significant and were a more effective risk marker compared to the single miRNAs. Conclusions: Women with metastatic breast cancer, especially CSII, presented up-regulated levels of miR-183, miR-494 and miR-21, which were associated with a poor prognosis. These miRNAs therefore represent new risk biomarkers of breast cancer metastasis and may be useful for future targeted therapies.

Project description:Breast cancer is a heterogeneous disease classified into 3 major subtypes based on the presence or absence of molecular markers for oestrogen receptors (ER), progesterone receptors (PR) and human epidermal growth factor-2 (Her2) . Hormone receptor-positive BC (ER+, PR+ and Her-2-), accounts for approximately 70% of patients. Patients with ER- BC account for approximately 30 % of all cases and commonly have a worse prognosis than ER+ patients (9). However, a significant proportion of ER- cases have good outcomes and could potentially benefit from a less aggressive therapy. Triple negative breast cancer (TNBC, ER-, PR- and Her-2-) accounts for approximately 15% of breast cancers and has the poorest outcomes. An hypoxic microenvironment is an important intrinsic component of solid tumours that can result in rapid proliferation of cancer cells and is associated with the lack of oxgyen and abnormal tumour blood vessels. Hypoxia stimulates the hypoxia inducible factor-1α (HIF-1α) that transactivates genes associated with angiogenesis, tumour growth, metastasis, metabolic reprogramming, and treatment resistance. HIF-1α is recognised to induce the expression of carbonic anhydrase IX (CAIX), an enzyme that has been attributed a central role in pH regulation and cancer progression and is particularly pronounced in peri necrotic tumour areas, high-grade BCs. The adaption to hypoxia is governed by multiple transcriptional and post-transcriptional changes in gene expression. Up to 1.5 % of the human genome is estimated to be transcriptionally responsive to hypoxia. Genes and pathways which have been identified as being responsive to hypoxia may have the potential to be used as prognostic or predictive markers, and furthermore, can help identify novel therapeutic targets. The aim of the present study was to gain a better understanding of the transcriptomic and protein pathways associated with CAIX in ER- BC to identify potential therapeutic targets against this aggressive phenotype.

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Identification of novel biomarkers associated with poor patient outcome in invasive breast carcinoma

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