Introduction: Breast cancer remains a significant scientific, clinical and societal challenge. This gap analysis has reviewed and critically assessed enduring issues and new challenges emerging from recent research, and proposes strategies for translating solutions into practice. Methods: More than 100 internationally recognised specialist breast cancer scientists, clinicians and healthcare professionals collaborated to address nine thematic areas: genetics, epigenetics and epidemiology; molecular pathology and cell biology; hormonal influences and endocrine therapy; imaging, detection and screening; current/novel therapies and biomarkers; drug resistance; metastasis, angiogenesis, circulating tumour cells, cancer ‘stem’ cells; risk and prevention; living with and managing breast cancer and its treatment. The groups developed summary papers through an iterative process which, following further appraisal from experts and patients, were melded into this summary account. Results: The 10 major gaps identified were: (1) understanding the functions and contextual interactions of genetic and epigenetic changes in normal breast development and during malignant transformation; (2) how to implement sustainable lifestyle changes (diet, exercise and weight) and chemopreventive strategies; (3) the need for tailored screening approaches including clinically actionable tests; (4) enhancing knowledge of molecular drivers behind breast cancer subtypes, progression and metastasis; (5) understanding the molecular mechanisms of tumour heterogeneity, dormancy, de novo or acquired resistance and how to target key nodes in these dynamic processes; (6) developing validated markers for chemosensitivity and radiosensitivity; (7) understanding the optimal duration, sequencing and rational combinations of treatment for improved personalised therapy; (8) validating multimodality imaging biomarkers for minimally invasive diagnosis and monitoring of responses in primary and metastatic disease; (9) developing interventions and support to improve the survivorship experience; (10) a continuing need for clinical material for translational research derived from normal breast, blood, primary, relapsed, metastatic and drug-resistant cancers with expert bioinformatics support to maximise its utility. The proposed infrastructural enablers include enhanced resources to support clinically relevant in vitro and in vivo tumour models; improved access to appropriate, fully annotated clinical samples; extended biomarker discovery, validation and standardisation; and facilitated cross-discipline working. Conclusions: With resources to conduct further high-quality targeted research focusing on the gaps identified, increased knowledge translating into improved clinical care should be achievable within five years.

BACKGROUND: Although lymphovascular invasion (LVI) has been associated with a poor outcome in patients with breast cancer, it is not included in most internationally recognized staging systems, including the American Joint Committee on Cancer tumor, lymph node, metastasis (TNM) classification. This is mainly because it remains unclear whether the presence of LVI is an independent, high‐risk criterion in clinically relevant staging subgroups.METHODS: The current study was based on a large and well characterized consecutive series of patients who had operable (pathologic T1 [pT1]‐pT2, pathologic N0 [pN0]‐pN3, M0) breast cancer (3812 informative cases) who were treated according to standard protocols at a single institution and who had long‐term follow‐up to assess the prognostic value of definite LVI in clinically and molecularly relevant staging subgroups.RESULTS: LVI was strongly associated with both breast cancer‐specific survival (BCSS) and distant metastasis‐free survival (DMFS) in the entire series and in different subgroups. Multivariate analyses identified LVI as an independent predictor of both BCSS and DMFS in patients with operable breast cancer overall; in the TNM clinical subgroups pT1a‐pT1c/pN0 and pT2/pN0; and in the molecular classes estrogen receptor (ER)‐positive, ER‐negative, human epidermal growth factor 2 [HER2]‐negative, and triple‐negative. In patients who had lymph node‐negative tumors, LVI could be used as a high‐risk criterion providing survival disadvantage equivalent to that provided by 1 or 2 involved lymph nodes (pN0 to pN1) and to that provided by 1 size category (pT1 to pT2). The use of immunohistochemistry for detecting an endothelial‐specific marker contributed to the prognostic significance of LVI when applied to routine LVI negative/possible cases.CONCLUSIONS: LVI provided a strong predictor of outcome in patients with invasive breast cancer and should be incorporated into breast cancer staging systems. Cancer 2012. © 2011 American Cancer Society.

Impaired apoptosis is one of the hallmarks of cancer. Caspase-3 and -8 are key regulators of the apoptotic response and have been shown to interact with the calpain family, a group of cysteine proteases, during tumorigenesis. The current study sought to investigate the prognostic potential of caspase-3 and -8 in breast cancer, as well as the prognostic value of combinatorial caspase and calpain expression. A large cohort (n = 1902) of early stage invasive breast cancer patients was used to explore the expression of caspase-3 and -8. Protein expression was examined using standard immunohistochemistry on tissue microarrays. High caspase-3 expression, but not caspase-8, is significantly associated with adverse breast cancer-specific survival (P = 0.008 and P = 0.056, respectively). Multivariate analysis showed that caspase-3 remained an independent factor when confounding factors were included (hazard ratio (HR) 1.347, 95% confidence interval (CI) 1.086–1.670; P = 0.007). The analyses in individual subgroups demonstrated the significance of caspase-3 expression in clinical outcomes in receptor positive (ER, PR or HER2) subgroups (P = 0.001) and in non-basal like subgroup (P = 0.029). Calpain expression had been previously assessed. Significant association was also found between high caspase-3/high calpain-1 and breast cancer-specific survival in the total patient cohort (P = 0.005) and basal-like subgroup (P = 0.034), as indicated by Kaplan–Meier analysis. Caspase-3 expression is associated with adverse breast cancer-specific survival in breast cancer patients, and provides additional prognostic values in distinct phenotypes. Combinatorial caspase and calpain expression can predict worse prognosis, especially in basal-like phenotypes. The findings warrant further validation studies in independent multi-centre patient cohorts.

Vascular endothelial cell growth factors (VEGF)-A, -C and -D have potent angio and lymphangiogenic functions in experimental models, although their role in the progression of human breast cancer is unclear. The aims of the current study were to examine the relationship between the expression of the aforementioned growth factors with the angio and lymphangiogenic characteristics of breast cancer, and to assess their suitability as potential prognostic factors. Paraffin-embedded sections of 177 primary invasive breast cancer, with complete clinical follow-up information for 10 years, were stained for VEGF-A, -C, -D, podoplanin and CD34 using standard immunohistochemical approaches. The expression of the growth factors was correlated with clinicopathological criteria and patients’ survival. Lymph vessel density (LVD) and microvessel density (MVD) were assessed and correlated with expression of the growth factors. Vascular endothelial cell growth factor-A, -C and -D were highly expressed in 40, 37 and 42% of specimens, respectively. High expression of VEGF-A and - C, but not of -D, was associated with a higher LVD (P=0.013 and P=0.014, respectively), a higher MVD (P<0.001 and P=0.002, respectively), the presence of lymph node metastasis (P<0.001 and P<0.001, respectively), distant metastasis (P=0.010 and P=0.008, respectively) and a shorter Overall Survival (P=0.029 and 0.028, respectively). In conclusion, breast cancers that express high levels of VEGF-A and -C are characterised by a poor prognosis, likely through the induction of angio and lymphangiogenesis. Examination of expression of VEGF-A and -C in breast cancer may be beneficial in the identification of a subset of tumours that have a higher probability of recurrence and metastatic spread.

The presence of vascular invasion (VI), encompassing both lymphovascular invasion (LVI) and blood vascular invasion (BVI), in breast cancer has been found to be a poor prognostic factor. It is not clear, however, which type of VI plays the major role in metastasis. The aims of this study were to use an endothelial subtype specific immunohistochemical approach to distinguish between LVI and BVI by comparing the differential expression of blood vascular (CD34 and CD31) and lymphatic markers (podoplanin/D2-40) to determine their prognostic role in a well-characterized group of breast cancer patients with known long-term follow-up. Sections from177 consecutive paraffin-embedded archival specimens of primary invasive breast cancer were stained for expression of podoplanin, D2-40, CD31, and CD34. BVI and LVI were identified and results were correlated with clinicopathologic criteria and patient survival. VI was detected in 56/177 specimens (31.6%); 54 (96.4%) were LVI and 2 (3.5%) were BVI. The presence of LVI was significantly associated with the presence of lymph node metastasis, larger tumor size, development of distant metastasis, regional recurrence and worse disease-free interval and overall survival. In multivariate analysis, LVI retained significance association with decreased disease-free interval and overall survival. In conclusion, VI in breast cancer is predominantly of lymph vessels and is a powerful independent prognostic factor, which is associated with risk of recurrence and death from the disease. The use of immunohistochemical staining with a lymphendothelial specific marker such as podoplanin/D2-40 increases the accuracy of identification of patients with tumor associated LVI.