Purpose Cisplatin is a chemotherapeutic agent not used routinely for breast cancer treatment. As a DNA cross-linking agent, cisplatin may be effective treatment for hereditary BRCA1-mutated breast cancers. Because sporadic triple-negative breast cancer (TNBC) and BRCA1-associated breast cancer share features suggesting common pathogenesis, we conducted a neoadjuvant trial of cisplatin in TNBC and explored specific biomarkers to identify predictors of response. Patients and Methods Twenty-eight women with stage II or III breast cancers lacking estrogen and progesterone receptors and HER2/Neu (TNBC) were enrolled and treated with four cycles of cisplatin at 75 mg/m2 every 21 days. After definitive surgery, patients received standard adjuvant chemotherapy and radiation therapy per their treating physicians. Clinical and pathologic treatment response were assessed, and pretreatment tumor samples were evaluated for selected biomarkers. Results Six (22%) of 28 patients achieved pathologic complete responses, including both patients with BRCA1 germline mutations;18 (64%) patients had a clinical complete or partial response. Fourteen (50%) patients showed good pathologic responses (Miller-Payne score of 3, 4, or 5), 10 had minor responses (Miller-Payne score of 1 or 2), and four (14%) progressed. All TNBCs clustered with reference basal-like tumors by hierarchical clustering. Factors associated with good cisplatin response include young age (P = .001), low BRCA1 mRNA expression (P = .03), BRCA1 promoter methylation (P = .04), p53 nonsense or frameshift mutations (P = .01), and a gene expression signature of E2F3 activation (P = .03). Conclusion Single-agent cisplatin induced response in a subset of patients with TNBC. Decreased BRCA1 expression may identify subsets of TNBCs that are cisplatin sensitive. Other biomarkers show promise in predicting cisplatin response.

UK Medical Research Council; Cancer Research UK; the National Institute for Health Research (UK); the Danish Council for Independent Research-Medical Sciences (FSS); Breast Cancer Research Foundation (New York); Fondation Luxembourgeoise contre le Cancer; the Fonds National de la Recherche Scientifique; Brussels Region (IRSIB-IP, Life Sciences 2007) and Walloon Region (Biowin-Keymarker); Sally Pearson Breast Cancer Fund; and the European Commission.

Chromosomal instability (CIN) is a common cause of tumour heterogeneity and poor prognosis in solid tumours and describes cell-cell variation in chromosome structure or number across a tumour population. In this article we consider evidence suggesting that CIN may be targeted and may influence response to distinct chemotherapy regimens, using HER2-positive breast cancer as an example. Pre-clinical models have indicated a role for HER2 signalling in initiating CIN and defective cell-cycle control, and evidence suggests that HER2-targeting may attenuate this process. Anthracyclines and platinum agents may target tumours with distinct patterns of karyotypic complexity, whereas taxanes may have preferential activity in tumours with relative chromosomal stability. A greater understanding of karyotypic complexity and identification of methods to directly examine and target CIN may support novel strategies to improve outcome in cancer.

To mimic in vivo conditions during chlamydial infections, Chlamydia trachomatis serovar D and Chlamydia pneumoniae CWL029 were cultured in low-oxygen atmospheres containing 4% O 2 , with parallel controls cultured in atmospheric air. Both were enriched with 5% CO 2 . The results showed a dramatic increase in the growth of C. pneumoniae but not of C. trachomatis.The chlamydial developmental cycle is biphasic, alternating between an infectious metabolically inactive elementary body (EB) specialized for extracellular survival and a noninfectious proliferating intracellular reticulate body (RB). During the course of an infection, the EB is endocytosed by a susceptible host cell into a host-derived vacuole, the chlamydial inclusion. After internalization, the EB develops into an RB, which proliferates by binary fission. Following several rounds of proliferation lasting 48 to 72 h, RBs transform into EBs and are released by the disruption of the host cell (for a review, see reference 9).Chlamydia trachomatis is an obligate human pathogen causing ocular and genital infections. Chlamydia pneumoniae causes respiratory tract infections, often asymptomatic, but may cause bronchitis and pneumonia (5). Traditionally, both C. trachomatis and C. pneumoniae have been studied in vitro by infecting cell culture monolayers and incubating the infected cells in incubators in a humid atmosphere containing atmospheric air enriched with 5% CO 2 , resulting in an oxygen concentration of approximately 20%. However, the in vivo oxygen tension is much lower, generally in the range of 3 to 6% (Table 1), and as different tissues have different oxygen requirements, the in vivo oxygen tension may vary considerably from tissue to tissue. The oxygen requirements of Chlamydia have never been evaluated before, but it is known that the oxygen tension of host tissue is important for viral replication and the viral life cycle (3) and that many infecting microorganisms are microaerophilic. As Chlamydia proliferates in vivo where the oxygen tension varies between different tissues, it is plausible that Chlamydia is also affected by the oxygen tension and would experience enhanced growth in tissues with optimum oxygen tension.C. trachomatis and C. pneumoniae produced enlarged inclusions in 4% oxygen. To determine the visible effect of low oxygen tension on chlamydial inclusions, infected HeLa cells were cultured on coverslips at 4% and 20% O 2 . HeLa 229 cells (ATCC, Rockville, MD) cultured in 24-well trays (TPP, Trasadingen, Switzerland) were infected with either C. trachomatis serovar D/UW-3/CX (ATCC) or C. pneumoniae CWL029 (ATCC) as previously described (12, 15) and cultured in the presence of cycloheximide in either 4% or 20% oxygen atmospheres. Low-oxygen atmospheres were achieved by placing trays with infected HeLa cells in an airtight custom-made box (40 by 30 by 16 cm [width by diameter by height]). An OX-500 Clark-type oxygen sensor (UniSense, Aarhus, Denmark) was placed inside the box to measure the oxygen concentration. The box was flushed w...

BackgroundExpression of the oestrogen receptor (ER) in breast cancer predicts benefit from endocrine therapy. Minimising the frequency of false negative ER status classification is essential to identify all patients with ER positive breast cancers who should be offered endocrine therapies in order to improve clinical outcome. In routine oncological practice ER status is determined by semi-quantitative methods such as immunohistochemistry (IHC) or other immunoassays in which the ER expression level is compared to an empirical threshold[1], [2]. The clinical relevance of gene expression-based ER subtypes as compared to IHC-based determination has not been systematically evaluated. Here we attempt to reduce the frequency of false negative ER status classification using two gene expression approaches and compare these methods to IHC based ER status in terms of predictive and prognostic concordance with clinical outcome.Methodology/Principal FindingsFirstly, ER status was discriminated by fitting the bimodal expression of ESR1 to a mixed Gaussian model. The discriminative power of ESR1 suggested bimodal expression as an efficient way to stratify breast cancer; therefore we identified a set of genes whose expression was both strongly bimodal, mimicking ESR expression status, and highly expressed in breast epithelial cell lines, to derive a 23-gene ER expression signature-based classifier. We assessed our classifiers in seven published breast cancer cohorts by comparing the gene expression-based ER status to IHC-based ER status as a predictor of clinical outcome in both untreated and tamoxifen treated cohorts. In untreated breast cancer cohorts, the 23 gene signature-based ER status provided significantly improved prognostic power compared to IHC-based ER status (P = 0.006). In tamoxifen-treated cohorts, the 23 gene ER expression signature predicted clinical outcome (HR = 2.20, P = 0.00035). These complementary ER signature-based strategies estimated that between 15.1% and 21.8% patients of IHC-based negative ER status would be classified with ER positive breast cancer.Conclusion/SignificanceExpression-based ER status classification may complement IHC to minimise false negative ER status classification and optimise patient stratification for endocrine therapies.