Lack of EGFR-activating mutations in European patients with triple-negative breast cancer could emphasise geographic and ethnic variations in breast cancer mutation profiles

INTRODUCTION: Triple-negative breast cancers (TNBCs) are characterised by lack of expression of hormone receptors and epidermal growth factor receptor 2 (HER-2). As they frequently express epidermal growth factor receptors (EGFRs), anti-EGFR therapies are currently assessed for this breast cancer subtype as an alternative to treatments that target HER-2 or hormone receptors. Recently, EGFR-activating mutations have been reported in TNBC specimens in an East Asian population. Because variations in the frequency of EGFR-activating mutations in East Asians and other patients with lung cancer have been described, we evaluated the EGFR mutational profile in tumour samples from European patients with TNBC. METHODS: We selected from a DNA tumour bank 229 DNA samples isolated from frozen, histologically proven and macrodissected invasive TNBC specimens from European patients. PCR and high-resolution melting (HRM) analyses were used to detect mutations in exons 19 and 21 of EGFR. The results were then confirmed by bidirectional sequencing of all samples. RESULTS: HRM analysis allowed the detection of three EGFR exon 21 mutations, but no exon 19 mutations. There was 100% concordance between the HRM and sequencing results. The three patients with EGFR exon 21 abnormal HRM profiles harboured the rare R836R SNP, but no EGFR-activating mutation was identified. CONCLUSIONS: This study highlights variations in the prevalence of EGFR mutations in TNBC. These variations have crucial implications for the design of clinical trials involving anti-EGFR treatments in TNBC and for identifying the potential target population

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Multiple Mechanisms of Iron-Induced Amyloid Beta-Peptide Accumulation in SHSY5Y Cells: Protective Action of Negletein

The increased accumulation of iron in the brain in Alzheimer's disease (AD) is well documented, and excess iron is strongly implicated in the pathogenesis of the disease. The adverse effects of accumulated iron in AD brain may include the oxidative stress, altered amyloid beta-metabolism and the augmented toxicity of metal-bound amyloid beta 42. In this study, we have shown that exogenously added iron in the form of ferric ammonium citrate (FAC) leads to considerable accumulation of amyloid precursor protein (APP) without a corresponding change in the concerned gene expression in cultured SHSY5Y cells during exposure up to 48 h. This phenomenon is also associated with increased β-secretase activity and augmented release of amyloid beta 42 in the medium. Further, the increase in β-secretase activity, in SHSY5Y cells, upon exposure to iron apparently involves reactive oxygen species (ROS) and NF-κB activation. The synthetic flavone negletein (5,6-dihydroxy-7-methoxyflavone), which is a known chelator for iron, can significantly prevent the effects of FAC on APP metabolism in SHSY5Y cells. Further, this compound inhibits the iron-dependent formation of ROS and also blocks the iron-induced oligomerization of amyloid beta 42 in vitro. In concentrations used in this study, negletein alone appears to have only marginal toxic effects on cell viability, but, on the other hand, the drug is capable of ameliorating the iron-induced loss of cell viability considerably. Our results provide the initial evidence of potential therapeutic effects of negletein, which should be explored in suitable animal models of AD