IntroductionBreast 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.MethodsMore 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.ResultsThe 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.ConclusionsWith 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.

Interactions between cancer cells and cancer-associated fibroblasts (CAFs) play an important role in tumour development and progression. In this study we investigated the functional role of CAFs in oesophageal adenocarcinoma (EAC). We used immunochemistry to analyse a cohort of 183 EAC patients for CAF markers related to disease mortality. We characterized CAFs and normal oesophageal fibroblasts (NOFs) using western blotting, immunofluorescence and gel contraction. Transwell assays, 3D organotypic culture and xenograft models were used to examine the effects on EAC cell function and to dissect molecular mechanisms regulating invasion. Most EACs (93%) contained CAFs with a myofibroblastic (α-SMA-positive) phenotype, which correlated significantly with poor survival [p = 0.016; HR 7. 1 (1.7–29.4)]. Primary CAFs isolated from EACs have a contractile, myofibroblastic phenotype and promote EAC cell invasion in vitro (Transwell assays, p ≤ 0.05; organotypic culture, p < 0.001) and in vivo (p ≤ 0.05). In vitro, this pro-invasive effect is modulated through the matricellular protein periostin. Periostin is secreted by CAFs and acts as a ligand for EAC cell integrins αvβ3 and αvβ5, promoting activation of the PI3kinase–Akt pathway. In patient samples, periostin expression at the tumour cell–stromal interface correlates with poor overall and disease-free survival. Our study highlights the importance of the tumour stroma in EAC progression. Paracrine interaction between CAF-secreted periostin and EAC-expressed integrins results in PI3 kinase–Akt activation and increased tumour cell invasion. Most EACs contain a myofibroblastic CAF-rich stroma; this may explain the aggressive, highly infiltrative nature of the disease, and suggests that stromal targeting may produce therapeutic benefit in EAC patients.

Replicative senescence in human fibroblasts is absolutely dependent on the function of the phosphoprotein p53 and correlates with activation of p53-dependent transcription. However, no evidence for posttranslational modification of p53 in senescence has been presented, raising the possibility that changes in transcriptional activity result from upregulation of a coactivator. Using a series of antibodies with phosphorylation-sensitive epitopes, we now show that senescence is associated with major changes at putative regulatory sites in the N and C termini of p53 consistent with increased phosphorylation at serine-15, threonine-18, and serine-376 and decreased phosphorylation at serine-392. Ionizing and UV radiation generated overlapping but distinct profiles of response, with increased serine-15 phosphorylation being the only common change. These results support a direct role for p53 in signaling replicative senescence and are consistent with the generation by telomere erosion of a signal which shares some but not all of the features of DNA double-strand breaks.Normal human somatic cells (with the possible exception of stem cells) are capable of only a finite number of cell divisions, after which they enter a nondividing though viable state termed replicative senescence (22,55). The significance of this phenomenon for human health is two-edged. On the one hand, it imposes a natural obstacle to clonal expansion, which probably plays a vital part in limiting tumor development (2, 38, 59). On the other hand, in some tissues, notably skin and blood vessels, it may account for progressive functional abnormality with advancing age. This may result directly from loss of regenerative capacity but also indirectly through senescence-associated biochemical changes, a good example being the increased collagenase secretion by ageing dermal fibroblasts, which may be significant even when only a minority of cells are overtly senescent (11,34). Knowledge of the underlying mechanisms of cellular senescence is therefore central to both cancer and aging research.We and others have demonstrated that one key signal pathway mediating replicative senescence involves the phosphoprotein p53, more widely recognized for its role as a tumor suppressor, which is known to mediate growth arrest in response to a wide variety of cellular stress signals including DNA damage (31, 40). Experimental abrogation of p53 function prevents fibroblasts from entering senescence normally and indeed can reverse established senescence, demonstrating that p53, if not sufficient, is certainly necessary for this process (5,6,20). Furthermore, growth arrest in senescence is tightly correlated with switching on of the transcriptional transactivation function of p53, as revealed by the use of reporter constructs and by DNA binding assays (1,7,50).Nevertheless, senescence has not thus far been shown to lead to any of the range of posttranslational modifications of the p53 protein which bring about its activation in response to other signals such as DNA damage (19). ...

When cells transform, phenotypic and genetic profiles can be dramatically altered. Nevertheless, a recent report identifying IgG in breast cancer cells was unexpected, revealing differentiation features normally associated with B lymphocytes. To extend these findings, we focused on immunoglobulin variable (V) region gene analysis using well-defined breast cancer cell lines expressing the epithelial marker, epithelial cell adhesion molecule (EpCAM). V H gene transcripts were identifiable by nested reverse transcription-PCR either as single or dual V, diversity (D), and joining (J) rearrangements in four of six lines, most being potentially functional. V(D)J transcripts were observed in sequential cultures, indicating stable expression. To exclude coexisting lymphocytes, each cell line was shown to be EBV negative, with CD19/CD20 and cytoplasmic/surface immunoglobulin also absent by flow cytometry. Identified V H transcripts were then sought in individual tumor cells, isolated as EpCAM + single cells by flow cytometry. Importantly, in three of three selected cell lines, V H genes were identifiable in a significant fraction (f32%) of single cells. In five of six identified V H genes, somatic mutations were apparent with no intraclonal variation, indicating cessation of mutational activity. V H transcripts were pre-and post-isotype switch, with activation of switch events evident from expressed germ-line switch transcripts in two of six lines. Strikingly, six of six cell lines expressed activation-induced cytidine deaminase (AID) essential for mutational and switch activity. These data suggest either a de novo rearrangement and modification of V H genes in epithelial tumor cells or assimilation of lymphocyte-derived chromatin. Constitutive AID activation in malignant epithelial cells further raises a potential for inducing aberrant mutational activity. (Cancer Res 2006; 66(8): 3996-4000)