R L Bowen

Early onset of breast cancer in a group of British black women.

Since there are no published data on breast cancer in British black women, we sought to determine whether, like African-American women, they present at a younger age with biologically distinct disease patterns. The method involved a retrospective review of breast cancer to compare age distributions and clinicopathological features between black women and white women in the UK, while controlling for socioeconomic status. All women presented with invasive breast cancer, between 1994 and 2005, to a single East London hospital. Black patients presented significantly younger (median age of 46 years), than white patients (median age of 67 years (P=0.001)). No significant differences between black and white population structures were identified. Black women had a higher frequency of grade 3 tumours, lymph node-positive disease, negative oestrogen receptor and progesterone receptor status and basal-like (triple negative status) tumours. There were no differences in stage at presentation; however, for tumours of ⩽2 cm, black patients had poorer survival than white patients (HR=2.90, 95% CI 0.98–8.60, P=0.05). Black women presented, on average, 21 years younger than white women. Tumours in younger women were considerably more aggressive in the black population, more likely to be basal-like, and among women with smaller tumours, black women were more than twice as likely to die of their disease. There were no disparities in socioeconomic status or treatment received. Our findings could have major implications for the biology of breast cancer and the detection and treatment of the disease in black women.

Molecular subtyping of DCIS: heterogeneity of breast cancer reflected in pre-invasive disease

Background:Molecular profiling has identified at least four subtypes of invasive breast carcinoma, which exhibit distinct clinical behaviour. There is good evidence now that DCIS represents the non-obligate precursor to invasive breast cancer and therefore it should be possible to identify similar molecular subtypes at this stage. In addition to a limited five-marker system to identify molecular subtypes in invasive breast cancer, it is evident that other biological molecules may identify distinct tumour subsets, though this has not been formally evaluated in DCIS.Methods:Tissue microarrays were constructed for 188 cases of DCIS. Immunohistochemistry was performed to examine the expression patterns of oestrogen receptor (ER), progesterone receptor (PR), Her2, EGFR, cytokeratin (CK) 5/6, CK14, CK17, CK18, β4-integrin, β6-integrin, p53, SMA, maspin, Bcl-2, topoisomerase IIα and P-cadherin. Hierarchical clustering analysis was undertaken to identify any natural groupings, and the findings were validated in an independent sample series.Results:Each of the intrinsic molecular subtypes described for invasive breast cancer can be identified in DCIS, though there are differences in the relative frequency of subgroups, in particular, the triple negative and basal-like phenotype is very uncommon in DCIS. Hierarchical cluster analysis identified three main subtypes of DCIS determined largely by ER, PR, Her2 and Bcl-2, and this classification is related to conventional prognostic indicators. These subtypes were confirmed in an analysis on independent series of DCIS cases.Conclusion:This study indicates that DCIS may be classified in a similar manner to invasive breast cancer, and determining the relative frequency of different subtypes in DCIS and invasive disease may shed light on factors determining disease progression. It also demonstrates a role for Bcl-2 in classifying DCIS, which has recently been identified in invasive breast cancer.

Matrix Metalloproteinase Single-Nucleotide Polymorphisms and Haplotypes Predict Breast Cancer Progression

Purpose: Polymorphisms within the promoter region of several matrix metalloproteinase (MMP) genes have been linked to alterations in the level of transcription. We hypothesized that an individuals MMP genotype and haplotype will influence breast tumor progression and help predict prognosis. Experimental Design: This study has evaluated the association between single-nucleotide polymorphisms (SNP) in the promoter regions of MMP-1, MMP-3, MMP-7, MMP-9, MMP-12, and MMP-13 and metastatic spread of breast cancer in 128 lymph node–negative and 93 lymph node–positive patients. The study cohort was of mixed ethnicity, with Caucasian patients comprising 65%. Associations between genotype and lymph node status were estimated by logistic regression and with overall survival using the method of Kaplan-Meier and log-rank test. Associations between haplotype and lymph node status were also investigated. Results: The data show a significant and independent association of the C/T genotype for MMP-9 [mixed ethnicities odds ratio 3.6, 95% confidence interval (95% CI) 1.2-11.1; Caucasian odds ratio 9.1, 95% CI 1.7-48.4] and the 2G/2G genotype for MMP-1 (mixed ethnicities odds ratio 3.9, 95% CI 1.7-9.4; Caucasian odds ratio 2.6, 95% CI 1.0-6.9) with lymph node–positive disease. MMP-1 2G/2G was associated with reduced survival (hazard ratio 3.1, 95% CI 1.1-8.7), although this is dependent on lymph node status. Two haplotypes, driven by the MMP-1 2G allele, were significantly associated with lymph node–positive disease and survival. Conclusions: These results suggest that MMP single-nucleotide polymorphisms influence breast cancer behavior and that the MMP-1 2G/2G genotype increases the risk of lymph node metastasis and predicts poor prognosis.

Therapeutic Targeting of Integrin αvβ6 in Breast Cancer

Background Integrin αvβ6 promotes migration, invasion, and survival of cancer cells; however, the relevance and role of αvβ6 has yet to be elucidated in breast cancer. Methods Protein expression of integrin subunit beta6 (β6) was measured in breast cancers by immunohistochemistry (n > 2000) and ITGB6 mRNA expression measured in the Molecular Taxonomy of Breast Cancer International Consortium dataset. Overall survival was assessed using Kaplan Meier curves, and bioinformatics statistical analyses were performed (Cox proportional hazards model, Wald test, and Chi-square test of association). Using antibody (264RAD) blockade and siRNA knockdown of β6 in breast cell lines, the role of αvβ6 in Human Epidermal Growth Factor Receptor 2 (HER2) biology (expression, proliferation, invasion, growth in vivo) was assessed by flow cytometry, MTT, Transwell invasion, proximity ligation assay, and xenografts (n ≥ 3), respectively. A student’s t-test was used for two variables; three-plus variables used one-way analysis of variance with Bonferroni’s Multiple Comparison Test. Xenograft growth was analyzed using linear mixed model analysis, followed by Wald testing and survival, analyzed using the Log-Rank test. All statistical tests were two sided. Results High expression of either the mRNA or protein for the integrin subunit β6 was associated with very poor survival (HR = 1.60, 95% CI = 1.19 to 2.15, P = .002) and increased metastases to distant sites. Co-expression of β6 and HER2 was associated with worse prognosis (HR = 1.97, 95% CI = 1.16 to 3.35, P = .01). Monotherapy with 264RAD or trastuzumab slowed growth of MCF-7/HER2-18 and BT-474 xenografts similarly (P < .001), but combining 264RAD with trastuzumab effectively stopped tumor growth, even in trastuzumab-resistant MCF-7/HER2-18 xenografts. Conclusions Targeting αvβ6 with 264RAD alone or in combination with trastuzumab may provide a novel therapy for treating high-risk and trastuzumab-resistant breast cancer patients.

The phosphorylated membrane estrogen receptor and cytoplasmic signaling and apoptosis proteins in human breast cancer

Estrogens play a central role in breast cancer development, and the estrogen receptor‒α (ERα) remains the single most important predictor of breast cancer prognosis. Therefore, it is crucial to elucidate pathways that may contribute to ER signaling in clinical specimens.

Reply: Early onset of breast cancer in British black women

Sir, We thank the authors for their interest in our study and apologise to them for having omitted citing their study (Wild et al, 2006) in our original paper. We did, however, make reference to their paper in our recent letter to the British Journal of Cancer (Bowen et al, 2008, in press). We note that this study found increased breast cancer mortality in those women born in West Africa and domiciled in the United Kingdom (not necessarily black African) whereas we found increased mortality in British black women but only in those with small tumours. In this recent letter, we have also described more fully the ethnicity of the black women in our cohort and while almost half were of Caribbean descent, at least one-third were black African or British. It is not clear that an analysis in the United Kingdom based on country of birth is comparable to one, such as ours, based on self-reported ethnicity. Also, by limiting our study to one area of East London and one referral hospital we have been able to control for socioeconomic status and variations in treatment practise and, thus, the outcome. We would also like to defend our age-related observations, even with the broad age groupings available to us. It was clear that the disease indeed does occur at younger ages, accounting for the different age ranges of the population, in the black population in the area of our study. We consider, therefore, that our conclusion is not a mistake although we do accept that our findings need to be substantiated in a national study of breast cancer using self-reported ethnicity to characterise the patterns of breast cancer better in British black women.

Abstract B046: Therapeutic targeting of integrin αvβ6 in high-risk breast cancer

Background: Integrin αvβ6 promotes migration, invasion and survival of cancer cells, however, the relevance and role of αvβ6 has yet to be elucidated in breast cancer. Methods: Protein expression of integrin subunit beta6 (β6) was measured in over 2000 breast cancers by immunohistochemistry and ITGB6 mRNA expression measured in the METABRIC dataset. Overall survival was assessed using Kaplan-Meier curves and bioinformatics statistical analyses were performed in R statistical environment v2.14.1. Using antibody (264RAD; supplied by AZ-Medimmune) blockade and siRNA knockdown of β6 in breast cell lines, the role of αvβ6 in HER2 biology (expression, proliferation, invasion, growth in vivo) was assessed by flow cytometry, MTT assays and Transwell invasion assays and xenografts, respectively. All statistical tests were two-sided. Results: High expression of either the mRNA or protein for the integrin subunit β6 correlated with very poor survival (HR=1.99, P=2.9x10-6) and increased metastases to distant sites (P=0.02). Co-expression of β6 and HER2 gave a worse prognosis (HR=3.43, P=4x10-12). HER2-driven invasion was mediated by αvβ6 in an Akt2-dependent manner. Monotherapy with 264RAD or trastuzumab, slowed growth of MCF-7/HER2-18 and BT-474 xenografts to a similar degree (P Conclusions: Targeting αvβ6 with 264RAD alone or in combination with trastuzumab may provide a novel therapy for treating high-risk and trastuzumab-resistant breast cancer patients, giving hope to the 70% of women treated who have, or develop, resistance. Moreover, routine determination of the level of expression of αvβ6 on breast cancers would stratify women into higher-risk categories, requiring enhanced therapeutic intervention. Citation Format: Kate M. Moore, Gareth J. Thomas, Stephen W. Duffy, Jane Warwick, Rhian Gabe, Patrick Chou, Ian O. Ellis, Andrew R. Green, Syed Haider, Kellie Brouilette, Antonio Saha, Sabari Vallath, Rebecca Bowen, Claudia Chelala, Diana Eccles, William J. Tapper, Alastair M. Thompson, Phillip Quinlan, Lee Jordan, Cheryl Gillett, Adam Brentnall, Sheila Violette, Paul Weinreb, Jane Kendrew, Simon T. Barry, Ian R. Hart, Louise Jones, John F. Marshall. Therapeutic targeting of integrin αvβ6 in high-risk breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B046.

Comment on 'High MET expression is an adverse prognostic factor in patients with triple-negative breast cancer'.

Comment on ‘High MET expression is an adverse prognostic factor in patients with triple-negative breast cancer’