http://breast-cancer-research.com/ The latest research articles published by Breast Cancer Research 2009-07-03T00:00:00Z This is an RSS newsfeed from BioMed Central It is intended to be used with an RSS reader. For more information about RSS newsfeeds from BioMed Central, visit http://www.biomedcentral.com/info/about/rss/ IntroductionMammography screening reduces breast cancer mortality through earlier diagnosis but may convey further benefit if screening is associated with optimized treatment through multidisciplinary medical care. In Norway, a national mammography screening program was introduced among women aged 50 to 69 years during 1995/6 to 2004. Also during this time, multidisciplinary breast cancer care units were implemented. Methods: We constructed three cohorts of breast cancer patients: 1) the pre-program group comprising women diagnosed and treated before mammography screening began in their county of residence, 2) the post-program group comprising women diagnosed and treated through multidisciplinary breast cancer care units in their county but before they had been invited to mammography screening; and 3) the screening group comprising women diagnosed and treated after invitation to screening. We calculated Kaplan-Meier plots and multivariable Cox proportional hazard models. Results: We studied 41,833 women with breast cancer. The nine-year breast cancer-specific survival rate was 0.66 (95%CI: 0.65 to 0.67) in the pre-program group; 0.72 (95%CI: 0.70 to 0.74) in the post-program group; and 0.84 (95%CI: 0.80 to 0.88) in the screening group. In multivariable analyses, the risk of death from breast cancer was 14% lower in the post-program group than in the pre-program group (hazard ratio 0.86; (95%CI: 0.78 to 0.95, P=0.003)). Conclusions: After 9 years follow-up, at least 33% of the improved survival is attributable to improved breast cancer management through multidisciplinary medical care. http://breast-cancer-research.com/content/11/4/R44 Mette Kalager Tor Haldorsen Michael Bretthauer Geir Hoff Steinar Thoresen Hans-Olov Adami Breast Cancer Research 2009, 11:R44 2009-07-03T00:00:00Z doi:10.1186/bcr2331 Breast Cancer Research 1465-5411 11 R44 2009-07-03T00:00:00Z PDF IntroductionRecent anticancer drugs have been made larger to selectively pass through tumor vessels and stay in the interstitium. Understanding drug movement in association to its size at the single molecule level and estimating the time needed to reach the targeted organ is indispensable for optimizing drug delivery because single cell-targeted therapy is the ongoing paradigm. This report describes the tracking of single solid nanoparticles in tumor xenografts and the estimation of arrival time. Methods: Different sized nanoparticles measuring 20, 40 and 100 nm were injected into the tail vein of the female Balb/c nu/nu mice bearing human breast cancer on their back. The movements of the nanoparticles were visualized through the dorsal skin fold chamber by the high-speed confocal microscopy that we manufactured. Results: An analysis of the particle trajectories revealed diffusion to be inversely related to the particle size and position in the tumor, while the velocity of the directed movement was related to the position. The difference in the velocity was the greatest for 40nm particles in the perivascular to the intercellular region: difference = 5.8 nm/s. The arrival time of individual nanoparticles to tumor cells was simulated. The estimated times for the 20, 40 and 100 nm particles to reach the tumor cells were 158.0, 218.5 and 389.4 min, respectively, after extravasation. Conclusions: This result suggests that the particle size can be individually designed for each goal. These data and methods are also important for understanding drug pharmacokinetics. Although this method may be subject to interference by surface molecules attached on the particles, it has the potential to elucidate the pharmacokinetics involved in constructing novel drug delivery systems involving cell-targeted therapy. http://breast-cancer-research.com/content/11/4/R43 Masaaki Kawai Hideo Higuchi Motohiro Takeda Yoshio Kobayashi Noriaki Ohuchi Breast Cancer Research 2009, 11:R43 2009-07-03T00:00:00Z doi:10.1186/bcr2330 Breast Cancer Research 1465-5411 11 R43 2009-07-03T00:00:00Z PDF IntroductionHeterochromatin protein 1 (HP1) associates with chromatin by binding to histone H3 and contributes to gene silencing. There are three isoforms of HP1 in mammals: HP1alpha, beta and gamma. Studies have shown that the level of HP1alpha is reduced in invasive human breast cancer cell lines such as MDA-MB-231 and HS578T compared with non-invasive cell lines such as MCF7 and T47D. It is hypothesized that reduced HP1alpha expression may lead to impaired epigenetic silencing of genes that are important in the acquisition of an invasive phenotype. We set out to determine whether reduced expression of HP1alpha in invasive breast cancer cell lines occurs at the level of transcription. Methods: We used transient transfection assays to investigate the mechanism of differential transcriptional activity of the human HP1alpha gene promoter in different cell lines. Mutational analysis of putative transcription factor binding sites in an HP1alpha gene reporter construct was performed to identify transcription factors responsible for the differential activity. siRNAmediated knockdown and chromatin immunoprecipitation experiments were performed to determine the role of a specific transcription factor in regulating the HP1alpha gene. Results: The transcription factor yin yang 1 (YY1) was found to play a role in differential transcriptional activity of the HP1alpha gene. Examination of the YY1 protein and mRNA levels revealed that both were reduced in the invasive cell line HS578T compared with MCF7 cells. YY1 knockdown in MCF7 cells resulted in a decreased level of HP1alpha mRNA, indicating that YY1 positively regulates HP1alpha expression. Chromatin immunoprecipitation experiments verified YY1 occupancy at the HP1alpha gene promoter in MCF7 cells but not HS578T cells. Overexpression of YY1 in HS578T cells decreased cell migration in a manner independent of HP1alpha overexpression. Conclusions: Our data suggests that a reduction of YY1 expression in breast cancer cells could contribute to the acquisition of an invasive phenotype through increased cell migration as well as by reduced expression of HP1alpha. http://breast-cancer-research.com/content/11/3/R42 Jason Lieberthal Marissa Kaminsky Christopher Parkhurst Naoko Tanese Breast Cancer Research 2009, 11:R42 2009-06-30T00:00:00Z doi:10.1186/bcr2329 Breast Cancer Research 1465-5411 11 R42 2009-06-30T00:00:00Z PDF IntroductionInhibitor of Apoptosis (IAPs) proteins are a family of proteins that can block apoptosis in normal cells and have been suggested to cause resistance to apoptosis in cancer. Overexpression of oncogenic receptor tyrosine kinases (RTKs) is common in breast cancer, in particular 20% of all cases show elevated Her2. Despite clinical success with the use of targeted therapies, such as Trastuzumab, only up to 35% of Her2 positive patients initially respond. We reasoned that IAP-mediated apoptosis resistance might contribute to this insensitivity to RTK therapy, in particular ErbB antagonists. Here we examine the levels of IAPs in breast cancer and evaluate whether targeting IAPs can enhance apoptosis in response to growth factor receptor antagonists and TRAIL. Methods: IAP levels were examined in a breast cancer cell line panel and in patient samples. IAPs were inhibited using siRNA or cell permeable mimetics of endogenous inhibitors. Cells were then exposed to TRAIL, Trastuzumab, Lapatinib, or Gefitinib for 48 hours. Examining nuclear morphology and staining for cleaved caspase 3 was used to score apoptosis. Proliferation was examined by Ki67 staining. Results: Four members of the IAP family, Survivin, XIAP, cIAP1 and cIAP2 were all expressed to varying extents in breast cancer cell lines or tumours. MDAMB468, BT474 and BT20 cells all expressed XIAP to varying extents. Depleting the cells of XIAP, overcame the intrinsic resistance of BT20 and MDAMB468 cells to TRAIL. Moreover, siRNA based depletion of XIAP or use of a Smac mimetic to target multiple IAPs, increased apoptosis in response to the ErbB antagonists, Trastuzumab, Lapatinib or Gefitinib in Her2-overexpressing BT474 cells, or Gefitinib in EGFR-overexpressing MDAMB468 cells. Conclusions: The novel findings of this study are that multiple IAPs are concomitantly expressed in breast cancers, and that, in combination with clinically relevant Her2 treatments, IAP antagonists promote apoptosis and reduce the cell turnover index of breast cancers. We also show that combination therapy of IAP antagonists with some pro-apoptotic agents, e.g. TRAIL, enhances apoptosis of breast cancer cells. In some cases, e.g. MDAMB468 cells, the enhanced apoptosis is profound. http://breast-cancer-research.com/content/11/3/R41 Fiona Foster Thomas Owens Jolanta Tanianis-Hughes Robert Clarke Keith Brennan Nigel Bundred Charles Streuli Breast Cancer Research 2009, 11:R41 2009-06-29T00:00:00Z doi:10.1186/bcr2328 Breast Cancer Research 1465-5411 11 R41 2009-06-29T00:00:00Z PDF Research that classifies breast cancers into homogenous subgroups could help to define public health strategies for preventing aggressive breast cancer subtypes. However, etiologic research on molecular breast cancer subtypes faces several challenges. Stratifying breast cancers into subgroups can reduce statistical power and therefore nontraditional analytical methods may be necessary. Integrating results across studies is hampered by varying definitions of molecular subtypes, with some studies using triple negative status and others using basal-specific markers to define basal-like cancers. In addition, triple negative and basal-like breast cancers appear to show strong associations with race, so the racial and ethnic composition of different datasets can make comparison across studies challenging. In spite of these challenges, some strong and consistent associations between triple negative or basal-like breast cancer and demographic variables are emerging, and there are hints that prevention strategies for this aggressive subtype of breast cancer may also be accessible. http://breast-cancer-research.com/content/11/3/104 Melissa Troester Theresa Swift-Scanlan Breast Cancer Research 2009, 11:104 2009-06-29T00:00:00Z doi:10.1186/bcr2323 Breast Cancer Research 1465-5411 11 104 2009-06-29T00:00:00Z PDF IntroductionThe expression of additional genes, other than estrogen receptor (ER), may be important to the hormone-responsive phenotype of breast cancer. Microarray analyses have revealed that forkhead box A1 (FOXA1) and GATA binding protein 3 (GATA-3) are expressed in close association with ER-alpha, both encoding for transcription factors with a potential involvement in the ER-alpha-mediated action in breast cancer. The purpose of this study was to explore if the expression of FOXA1 and GATA-3 may provide an opportunity to stratify subsets of patients that could have better outcome, among the ER-alpha-negative/poor prognosis breast cancer group. Methods: We evaluate FOXA1 and GATA-3 expression in 249 breast carcinomas by immunohistochemistry, associating it with breast cancer molecular markers, clinicopathological features and patient's survival. The clinicopathological features and immunohistochemical markers of the tumours were compared using the chi-square test and ANOVA. Disease-free survival was analysed through Kaplan-Meier survival curves and Cox regression. Results: FOXA1 expression was demonstrated in 42% of invasive carcinomas, while GATA-3 was detected in 48% of the cases. FOXA1 expression was inversely associated with tumour size, Nottingham prognostic index, histological grade, lymph vascular invasion, lymph node stage and human epidermal growth factor receptor-2 (HER-2) overexpression, while GATA-3 expression showed inverse association with histological grade and HER-2. Both FOXA1 and GATA-3 were directly associated with ER-alpha and progesterone receptor (PR). Among FOXA1 positive tumours, 83.1% are comprised in the luminal A subtype, similar to GATA-3 where 87.7% of positive tumours were classified within this molecular subtype. In the subset of ER-alpha-negative patients, those who were FOXA1-negative had a 3.61-fold increased risk of breast cancer recurrence when compared to the FOXA1-positive. Conclusions: FOXA1 was a significant predictor of good outcome in breast cancer, whereas GATA-3 was an important luminal marker. The expression of FOXA1 may be used for risk stratification among ER-alpha-negative patients. http://breast-cancer-research.com/content/11/3/R40 Andre Albergaria Joana Paredes Barbara Sousa Fernanda Milanezi Vitor Carneiro Joana Bastos Sandra Costa Daniella Vieira Nair Lopes Eric Lam Nuno Lunet Fernando Schmitt Breast Cancer Research 2009, 11:R40 2009-06-23T00:00:00Z doi:10.1186/bcr2327 Breast Cancer Research 1465-5411 11 R40 2009-06-23T00:00:00Z PDF IntroductionWe evaluated whether CK19, one of the main cytoskeleton proteins of epithelial cells, is released as full-length protein from viable tumor cells and whether this property is relevant for metastatic progression in breast cancer patients. Methods: EPISPOT (EPithelial ImmunoSPOT) assays were performed to analyze the release of full-length CK19 by carcinoma cells of various origins, and the sequence of CK19 was analyzed by mass spectrometry. Additional functional experiments with cycloheximide, brefeldin A or vincristine were done to analyze the biology of the CK19-release. CK19-EPISPOT was used to detect disseminated tumor cells in bone marrow (BM) of 45 breast cancer patients who were then followed over a median of 6 years. Results: CK19 was expressed and released by colorectal (HT-29, HCT116, Caco-2) and breast (MCF-7, SKBR3 and MDA-MB-231) cancer cell lines. The CK19-EPISPOT was more sensitive than the CK19-ELISA. Dual fluorescent EPISPOT with antibodies against different CK19 epitopes showed the release of the full-length CK19 which was confirmed by mass spectrometry. Functional experiments indicated that CK19 release was an active process and not simply the consequence of cell death. CK19-releasing cells (RC) were detectable in BM of 44% to 70% of breast cancer patients. This incidence and the number of CK19-RC were correlated to the presence of overt metastases, and patients with CK19-RC had a reduced survival as compared to patients without these cells (P=0.025, log-rank test; P=0.0019, hazard ratio 4.7, multivariate analysis). Conclusions: Full-length CK19 is released by viable epithelial tumor cells, and CK19-RC might constitute a biological active subset of breast cancer cells with high metastatic properties. http://breast-cancer-research.com/content/11/3/R39 Catherine Alix-Panabieres Jean-Pierre Vendrell Monique Slijper Olivier Pelle Eric Barbotte Gregoire Mercier William Jacot Michel Fabbro Klaus Pantel Breast Cancer Research 2009, 11:R39 2009-06-23T00:00:00Z doi:10.1186/bcr2326 Breast Cancer Research 1465-5411 11 R39 2009-06-23T00:00:00Z PDF IntroductionSex steroids, insulin-like growth factors (IGF) and prolactin are breast cancer risk factors but whether their effects are mediated through mammographic density, one of the strongest risk factors for breast cancer, is unknown. If such a hormonal basis of mammographic density exists, hormones may underlie ethnic differences in both mammographic density and breast cancer incidence rates. Methods: In a cross-sectional study of 270 post-menopausal Caucasian and Afro-Caribbean women attending a population-based breast screening service in London UK, we investigated whether plasma biomarkers (oestradiol, oestrone, sex hormone binding globulin (SHBG), testosterone, prolactin, leptin, insulin-like growth factor (IGF)-I, IGF-II and IGF binding protein 3 (IGFBP3)) were related to and explained ethnic differences in percent density, dense area and non-dense area, measured in Cumulus using the threshold method. Results: Mean levels of oestrogens, leptin and IGF-I:IGFBP3 were higher whereas SHBG and IGF-II:IGFBP3 were lower in Afro-Caribbeans compared to Caucasians after adjustment for higher mean body mass index (BMI) in the former group (by 3.2 kg/m2 (95% CI: 1.8, 4.5)). Age-adjusted percent density was lower in Afro-Caribbean compared to Caucasian women by 5.4% (absolute difference), but was attenuated to 2.5% (95% confidence interval (CI): -0.2, 5.1) upon BMI adjustment. Despite ethnic differences in biomarkers and in percent density, strong ethnic-age-adjusted inverse associations of oestradiol, leptin and testosterone with percent density were completely attenuated upon adjustment for BMI. There were no associations of IGF-I, IGF-II or IGFBP3 with percent density or dense area. We found weak evidence that a 2-fold increase in prolactin and oestrone levels were associated, respectively, with an increase (by 1.7% (95% CI: -0.3, 3.7)) and decrease (by 2.0% (95% CI: 0, 4.1)) in density after adjustment for BMI. Conclusions: These findings suggest that sex hormone and IGF levels are not associated with BMI-adjusted percent mammographic density in cross-sectional analyses of post-menopausal women and thus do not explain ethnic differences in density. Mammographic density may still, however, be influenced by much higher pre-menopausal hormone levels. http://breast-cancer-research.com/content/11/3/R38 Valerie McCormack Mitch Dowsett Elizabeth Folkerd Nichola Johnson Claire Palles Ben Coupland Jeff Holly Sarah Vinnicombe Nicholas Perry Isabel dos Santos Silva Breast Cancer Research 2009, 11:R38 2009-06-22T00:00:00Z doi:10.1186/bcr2325 Breast Cancer Research 1465-5411 11 R38 2009-06-22T00:00:00Z PDF IntroductionClassification of breast cancers according to the HER-2 oncogene status is of central importance in the selection of post-surgical therapies. A decrease in the proportion of HER-2 positive breast cancer has been suspected, but no data on the incidence trends at population level have been reported. Methods: We studied the proportion of HER-2 positive breast cancers by chromogenic in situ hybridization (CISH) in three cohorts (years 1982 to 1986 (n=310), 1989 to 1992, (n=108), and 2004 to 2005 (n=713) in the population of the Pirkanmaa hospital district (approximately 220,000 women). Cancer incidence rates were age-adjusted to the world standard population. Results: The proportion of HER-2 positive breast cancer declined from 21.6% (average in 1982 to 1986) to 13.6% (years 2004 to 2005). However, during the same time period the age-adjusted incidence of all invasive breast cancers had increased by 40%. These opposite trends balanced each other and indicated that the incidence of HER-2 positive breast cancer has remained unchanged (Poisson regression coefficient for time trend 1.000; 95% CI; 0.989 to 1.012). In contrast, the incidence of HER-2 negative cancer showed 2% annual increase (Poisson regression coefficient 1.021, 95% CI; 1.016 to 1.026). Although HER-2 negative cancers were more likely to be diagnosed by mammography screening, the changes were more likely to be explained by etiological risk factors favoring HER-2 negative (and hormone receptor positive) disease such as menopausal hormone therapy. Conclusions: These results document a significant decrease in the proportion of HER-2 positive breast cancer. However, the incidence of HER-2 positive cancer at the population level was found unchanged. http://breast-cancer-research.com/content/11/3/R37 Katri Koninki Minna Tanner Anssi Auvinen Jorma Isola Breast Cancer Research 2009, 11:R37 2009-06-18T00:00:00Z doi:10.1186/bcr2322 Breast Cancer Research 1465-5411 11 R37 2009-06-18T00:00:00Z PDF IntroductionWe have shown previously that treatment with pegylated leptin peptide receptor antagonist 2 (PEG-LPrA2) reduced the expression of vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor type 2 (VEGFR2) and growth of 4T1-breast cancer (BC) in syngeneic mice. In this investigation, PEG-LPrA2 was used to evaluate whether the inhibition of leptin signaling has differential impact on the expression of pro-angiogenic and pro-proliferative molecules and growth of human estrogen receptor positive (ER+) and negative (ER-) BC xenografts hosted by immunodeficient mice. Methods: To test the contribution of leptin signaling to BC growth and expression of leptin-targeted molecules, PEG-LPrA2 treatment was applied to severe immunodeficient mice hosting established ER+ (MCF-7 cells; ovariectomized/supplemented with E2) and ER- BC xenografts (MDA-MB231 cells). To further assess leptin and PEG-LPrA2 effects on ER+ and ER- BC the expression of VEGF and VEGFR2 (protein and mRNA) were investigated in cell cultures. Results: PEG-LPrA2 more effectively reduced the growth of ER+ (>40 fold) than ER- BC (2 fold) and expression of pro-angiogenic (VEGF/VEGFR2, leptin/leptin receptor OB-R, and interleukin 1 receptor type I, IL-1R tI) and pro-proliferative molecules (proliferating cell nuclear antigen, PCNA and cyclin D1) in ER+ than in ER- BC. Mouse tumor stroma in ER+ BC expressed high levels of VEGF and leptin that was induced by leptin signaling. Leptin up-regulated the transcriptional expression of VEGF/VEGFR2 in MCF-7 and MDA-MB231 cells. Conclusions: These results suggest that leptin signaling plays an important role in the growth of both ER+ and ER- BC that is associated to the leptin regulation of pro-angiogenic and pro-proliferative molecules. These data provide support for the potential use of leptin-signaling inhibition as a novel treatment of ER+ and ER- BC. http://breast-cancer-research.com/content/11/3/R36 Ruben Rene Gonzalez Amber Watters Yanbo Xu Udai Singh David Mann Bo Rueda Manuel Penichet Breast Cancer Research 2009, 11:R36 2009-06-16T00:00:00Z doi:10.1186/bcr2321 Breast Cancer Research 1465-5411 11 R36 2009-06-16T00:00:00Z PDF