Advances in DNA and RNA sequencing revealed substantially greater genomic complexity in breast cancer than simple models of a few driver mutations would suggest. Only very few, recurrent mutations or ...copy‐number variations in cancer‐causing genes have been identified. The two most common alterations in breast cancer are TP53 (affecting the majority of triple‐negative breast cancers) and PIK3CA (affecting almost half of estrogen receptor‐positive cancers) mutations, followed by a long tail of individually rare mutations affecting <1%–20% of cases. Each cancer harbors from a few dozen to a few hundred potentially high‐functional impact somatic variants, along with a much larger number of potentially high‐functional impact germline variants. It is likely that it is the combined effect of all genomic variations that drives the clinical behavior of a given cancer. Furthermore, entirely new classes of oncogenic events are being discovered in the noncoding areas of the genome and in noncoding RNA species driven by errors in RNA editing. In light of this complexity, it is not unexpected that, with the exception of HER2 amplification, no robust molecular predictors of benefit from targeted therapies have been identified. In this review, we summarize the current genomic portrait of breast cancer, focusing on genetic aberrations that are actively being targeted with investigational drugs.
Implications for Practice:
Next‐generation sequencing is now widely available in the clinic, but interpretation of the results is challenging, and its impact on treatment selection is often limited. This work provides an overview of frequently encountered molecular abnormalities in breast cancer and discusses their potential therapeutic implications. This review emphasizes the importance of administering investigational targeted therapies, or off‐label use of approved targeted drugs, in the context of a formal clinical trial or registry programs to facilitate learning about the clinical utility of tumor target profiling.
This review summarizes the current genomic portrait of breast cancer, focusing on genetic aberrations that are actively being targeted with investigational drugs. The importance of administering investigational targeted therapies, or off‐label use of approved targeted drugs, in the context of a formal clinical trial or registry programs to facilitate learning about the clinical utility of tumor target profiling is emphasized.
Sequence variations in coding and non-coding regions of the genome can affect gene expression and signalling pathways, which in turn may influence disease outcome.
In this study, we integrated ...somatic mutations, gene expression and clinical data from 930 breast cancer patients included in the TCGA database. Genes associated with single mutations in molecular breast cancer subtypes were identified by the Mann-Whitney U-test and their prognostic value was evaluated by Kaplan-Meier and Cox regression analyses. Results were confirmed using gene expression profiles from the Metabric data set (n = 1988) and whole-genome sequencing data from the TCGA cohort (n = 117).
The overall mutation rate in coding and non-coding regions were significantly higher in ER-negative/HER2-negative tumours (P = 2.8E-03 and P = 2.4E-07, respectively). Recurrent sequence variations were identified in non-coding regulatory regions of several cancer-associated genes, including NBPF1, PIK3CA and TP53. After multivariate regression analysis, gene signatures associated with three coding mutations (CDH1, MAP3K1 and TP53) and two non-coding variants (CRTC3 and STAG2) in cancer-related genes predicted prognosis in ER-positive/HER2-negative tumours.
These findings demonstrate that sequence alterations influence gene expression and oncogenic pathways, possibly affecting the outcome of breast cancer patients. Our data provide potential opportunities to identify non-coding variations with functional and clinical relevance in breast cancer.
Uncovering the metabolomic fingerprint of breast cancer Oakman, Catherine; Tenori, Leonardo; Biganzoli, Laura ...
The international journal of biochemistry & cell biology,
07/2011, Letnik:
43, Številka:
7
Journal Article
Recenzirano
Metabolomics, the study of metabolites and small intermediate molecules, may play a key role in further elucidation of breast cancer. This dynamic, simultaneous assessment of thousands of metabolites ...allows identification of the presence, concentration and fluxes of specific metabolites, and recognition of the critical metabolic pathways recruited in carcinogenesis. Studies of tumour cell and tissue allow focused analysis on the tumour, whilst studies of biofluids have the appeal of concurrent assessment of tumour and host. Elucidation of these metabolites and pathways may provide essential insights into both the intercellular environment and host/tumour interaction, allowing recognition of new biomarkers for diagnosis and prediction of outcome, new therapy targets and novel approaches for monitoring response and toxicity. Certainly, the field of metabolomics may evolve as a valuable, complementary clinical tool. In this review, current metabolomic data in breast cancer will be presented. The dominant metabolic pathways and metabolite disturbances associated with malignant transformation of breast cells will be outlined, leading to an overview of potential clinical implications for individuals with breast cancer.
Breast cancer is a heterogeneous tumor type characterized by a complex spectrum of molecular aberrations, resulting in a diverse array of malignant features and clinical outcomes. Deciphering the ...molecular mechanisms that fuel breast cancer development and act as determinants of aggressiveness is a primary need to improve patient management. Among other alterations, aberrant expression of microRNAs has been found in breast cancer and other human tumors, where they act as either oncogenes or tumor suppressors by virtue of their ability to finely modulate gene expression at the post-transcriptional level. In this study, we describe a new role for miR-181a/b as negative regulators of the DNA damage response in breast cancer, impacting on the expression and activity of the stress-sensor kinase ataxia telangiectasia mutated (ATM). We report that miR-181a and miR-181b were overexpressed in more aggressive breast cancers, and their expression correlates inversely with ATM levels. Moreover we demonstrate that deregulated expression of miR-181a/b determines the sensitivity of triple-negative breast cancer cells to the poly-ADP-ribose-polymerase1 (PARP1) inhibition. These evidences suggest that monitoring the expression of miR-181a/b could be helpful in tailoring more effective treatments based on inhibition of PARP1 in breast and other tumor types.
Patients with primary HER2-positive breast cancer benefit from HER2-targeted therapies. Nevertheless, a significant proportion of these patients die of disease progression due to mechanisms of drug ...resistance. MicroRNAs (miRNAs) are emerging as critical core regulators of drug resistance that act by modulating the epithelial-to-mesenchymal transition (EMT) and cancer-related immune responses. In this study, we investigated the association between the expression of a specific subset of 14 miRNAs involved in EMT processes and immune functions and the response to neoadjuvant trastuzumab and chemotherapy in 52 patients with HER2-overexpressing breast tumors. The expression of only a single miRNA, miR-21, was significantly associated with residual disease (p = 0.030) and increased after trastuzumab-chemotherapy (p = 0.012). A target prediction analysis coupled with in vitro and in vivo validations revealed that miR-21 levels inversely correlated with the expression of PTEN (rs = -0.502; p = 0.005) and PDCD4 (rs = -0.426; p = 0.019), which differentially influenced the drug sensitivity of HER2-positive breast cancer cells. However, PTEN expression was only marginally associated with residual disease. We further demonstrated that miR-21 was able to affect the response to both trastuzumab and chemotherapy, triggering an IL-6/STAT3/NF-κB-mediated signaling loop and activating the PI3K pathway. Our findings support the ability of miR-21 signaling to sustain EMT and shape the tumor immune microenvironment in HER2-positive breast cancer. Collectively, these data provide a rationale for using miR-21 expression as a biomarker to select trastuzumab-chemotherapy-resistant HER2-positive breast cancer patients who may benefit from treatments containing PI3K inhibitors or immunomodulatory drugs.
The DNA-damage response (DDR) ensures genome stability and proper inheritance of genetic information, both of which are essential to survival. It is presently unclear to what extent other signaling ...pathways modulate DDR function. Here we show that Notch receptor binds and inactivates ATM kinase and that this mechanism is evolutionarily conserved in Caenorhabditis elegans, Xenopus laevis and humans. In C. elegans, the Notch pathway impairs DDR signaling in gonad germ cells. In mammalian cells, activation of human Notch1 leads to reduced ATM signaling in a manner independent of Notch1 transcriptional activity. Notch1 binds directly to the regulatory FATC domain of ATM and inhibits ATM kinase activity. Notch1 and ATM activation are inversely correlated in human breast cancers, and inactivation of ATM by Notch1 contributes to the survival of Notch1-driven leukemia cells upon DNA damage.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, UILJ, UKNU, UL, UM, UPUK
We hypothesized that distinct biological processes might be associated with prognosis and chemotherapy sensitivity in the different types of breast cancers.
We performed gene set analyses with ...BRB-ArrayTools statistical software including 2331 functionally annotated gene sets (ie, lists of genes that correspond to a particular biological pathway or biochemical function) assembled from Ingenuity Pathway Analysis and Gene Ontology databases corresponding to almost all known biological processes. Gene set analysis was performed on gene expression data from three cohorts of 234, 170, and 175 patients with HER2-normal lymph node-negative breast cancer who received no systemic adjuvant therapy to identify gene sets associated prognosis and three additional cohorts of 198, 85, and 62 patients with HER2-normal stage I-III breast cancer who received preoperative chemotherapy to identify gene sets associated with pathological complete response to therapy. These analyses were performed separately for estrogen receptor (ER)-positive and ER-negative breast cancers. Interaction between gene sets and survival and treatment response by breast cancer subtype was assessed in individual datasets and also in pooled datasets. Statistical significance was estimated with permutation test. All statistical tests were two-sided.
For ER-positive cancers, from 370 to 434 gene sets were associated with prognosis (P ≤ .05) and from 209 to 267 gene sets were associated with chemotherapy response in analysis by individual dataset. For ER-positive cancers, 131 gene sets were associated with prognosis and 69 were associated with pathological complete response (P ≤.001) in pooled analysis. Increased expression of cell cycle-related gene sets was associated with poor prognosis, and B-cell immunity-related gene sets were associated with good prognosis. For ER-negative cancers, from 175 to 288 gene sets were associated with prognosis and from 212 to 285 gene sets were associated with chemotherapy response. In pooled analyses of ER-negative cancers, 14 gene sets were associated with prognosis and 23 were associated with response. Gene sets involved in sphingolipid and glycolipid metabolism were associated with better prognosis and those involved in base excision repair, cell aging, and spindle microtubule regulation were associated with chemotherapy response.
Different biological processes were associated with prognosis and chemotherapy response in ER-positive and ER-negative breast cancers.
Introduction: Maintenance of genome stability requires the integrity of the DNA repair machinery. DNA damage response (DDR) determines cell fate and regulates the expression of microRNAs (miRNAs), ...which in turn may also regulate important components of the DNA repair machinery.Areas covered: In this review, we describe the bidirectional connection between miRNAs and DDR and their link with important biological functions such as, DNA repair, cell cycle and apoptosis in cancer. Furthermore, we highlight the potential implications of recent findings on miRNA/DDR in determining chemotherapy response in cancer patients, and the use of these biomarkers for novel potential therapeutic approaches.Expert opinion: Defects in the DDR and deregulation of miRNAs are important hallmarks of human cancer. A full understanding of the mechanisms underlying the connection between miRNAs and DDR/DNA repair pathways will positively impact our knowledge on human tumor biology and on different responses to distinct drugs. Specific miRNAs interact with distinct DDR components and are promising targets for enhancing the effects of, and/or to overcome the resistance to, conventional chemotherapeutic agents. Finally, the development of innovative tools to deliver miRNA-targeting oligonucleotides may represents novel types of cancer interventions in clinic.
Primary growth hormone resistance or growth hormone insensitivity syndrome, also known as Laron syndrome, is a hereditary disease caused by deletions or different types of mutations in the growth ...hormone receptor gene or by post-receptor defects. This disorder is characterized by a clinical appearance of severe growth hormone deficiency with high levels of circulating growth hormone in contrast to low serum insulin-like growth factor 1 values.
We report the case of a 15-year-old Caucasian girl who was diagnosed with Silver-Russell syndrome at the age of four and a half years. Recombinant growth hormone was administered for 18 months without an appropriate increase in growth velocity. At the age of seven years, her serum growth hormone levels were high, and an insulin-like growth factor 1 generation test did not increase insulin-like growth factor 1 levels (baseline insulin-like growth factor 1 levels, 52 μg/L; reference range, 75 μg/L to 365 μg/L; and peak, 76 μg/L and 50 μg/L after 12 and 84 hours, respectively, from baseline). The genetic analysis showed that the patient was homozygous for the R217X mutation in the growth hormone receptor gene, which is characteristic of Laron syndrome. On the basis of these results, the diagnosis of primary growth hormone insensitivity syndrome was made, and recombinant insulin-like growth factor 1 therapy was initiated. The patient's treatment was well tolerated, but unexplained central hypothyroidism occurred at the age of 12.9 years. At the age of 15 years, when the patient's sexual development was almost completed and her menstrual cycle occurred irregularly, her height was 129.8 cm, which is 4.71 standard deviations below the median for normal girls her age.
The most important functional tests for the diagnosis of growth hormone insensitivity are the insulin-like growth factor 1 generation test and genetic analysis. Currently, the only effective treatment is daily administration of recombinant insulin-like growth factor 1 starting from early childhood. However, these patients show a dramatically impaired final height. In our case, unexplained central hypothyroidism occurred during treatment.
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