Tumor Biomechanics Alters Metastatic Dissemination of Triple Negative Breast Cancer via Rewiring Fatty Acid Metabolism.

In recent decades, the role of tumor biomechanics on cancer cell behavior at the primary site has been increasingly appreciated. However, the effect of primary tumor biomechanics on the latter stages of the metastatic cascade, such as metastatic seeding of secondary sites and outgrowth remains underappreciated. This work sought to address this in the context of triple negative breast cancer (TNBC), a cancer type known to aggressively disseminate at all stages of disease progression. Using mechanically tuneable model systems, mimicking the range of stiffness's typically found within breast tumors, it is found that, contrary to expectations, cancer cells exposed to softer microenvironments are more able to colonize secondary tissues. It is shown that heightened cell survival is driven by enhanced metabolism of fatty acids within TNBC cells exposed to softer microenvironments. It is demonstrated that uncoupling cellular mechanosensing through integrin ß1 blocking antibody effectively causes stiff primed TNBC cells to behave like their soft counterparts, both in vitro and in vivo. This work is the first to show that softer tumor microenvironments may be contributing to changes in disease outcome by imprinting on TNBC cells a greater metabolic flexibility and conferring discrete cell survival advantages.

Oral Selective Estrogen Receptor Degraders (SERDs) in Breast Cancer: Advances, Challenges, and Current Status.

Several endocrine therapies are currently available for the treatment of estrogen receptor (ER) positive breast cancer, but the clinical benefit of these agents is limited by endocrine therapy drug resistance. A common mechanism of endocrine therapy resistance is ESR1 mutations. The first-generation selective estrogen receptor degrader (SERD) fulvestrant has activity against ESR1 mutant tumors but requires intramuscular injection and has poor bioavailability that precludes optimal drug dosing. This led to the development of second-generation SERDs which are potent and have improved oral bioavailability and pharmacokinetics. Several of these oral SERDs are now in phase III trials in both the early and advanced ER positive breast cancer settings. This review summarizes the background of oral SERD development, the current status and future perspectives.

Effects of Endocrine Therapy on Cognitive Function in Patients with Breast Cancer: A Comprehensive Review.

Endocrine therapy forms the backbone of systemic therapy for the majority of persons with early and late-stage breast cancer. However, the side effects can negatively affect quality of life, and impact treatment adherence and overall oncological outcomes. Adverse effects on cognition are common, underreported and challenging to manage. We aim to describe the nature, incidence, risk factors and underlying mechanisms of endocrine therapy-induced cognitive dysfunction. We conducted a comprehensive literature review of the studies reporting on cognitive dysfunction associated with endocrine therapies for breast cancer. We also summarise prevention and treatment strategies, and ongoing research. Given that patients are taking endocrine therapies for longer durations than ever before, it is essential that these side effects are managed pro-actively within a multi-disciplinary team in order to promote adherence to endocrine therapy and improve patients' quality of life.

A single-cell and spatially resolved atlas of human breast cancers.

Breast cancers are complex cellular ecosystems where heterotypic interactions play central roles in disease progression and response to therapy. However, our knowledge of their cellular composition and organization is limited. Here we present a single-cell and spatially resolved transcriptomics analysis of human breast cancers. We developed a single-cell method of intrinsic subtype classification (SCSubtype) to reveal recurrent neoplastic cell heterogeneity. Immunophenotyping using cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) provides high-resolution immune profiles, including new PD-L1/PD-L2+ macrophage populations associated with clinical outcome. Mesenchymal cells displayed diverse functions and cell-surface protein expression through differentiation within three major lineages. Stromal-immune niches were spatially organized in tumors, offering insights into antitumor immune regulation. Using single-cell signatures, we deconvoluted large breast cancer cohorts to stratify them into nine clusters, termed 'ecotypes', with unique cellular compositions and clinical outcomes. This study provides a comprehensive transcriptional atlas of the cellular architecture of breast cancer.

Cryopreservation of human cancers conserves tumour heterogeneity for single-cell multi-omics analysis.

BACKGROUND: High throughput single-cell RNA sequencing (scRNA-Seq) has emerged as a powerful tool for exploring cellular heterogeneity among complex human cancers. scRNA-Seq studies using fresh human surgical tissue are logistically difficult, preclude histopathological triage of samples, and limit the ability to perform batch processing. This hindrance can often introduce technical biases when integrating patient datasets and increase experimental costs. Although tissue preservation methods have been previously explored to address such issues, it is yet to be examined on complex human tissues, such as solid cancers and on high throughput scRNA-Seq platforms. METHODS: Using the Chromium 10X platform, we sequenced a total of ~ 120,000 cells from fresh and cryopreserved replicates across three primary breast cancers, two primary prostate cancers and a cutaneous melanoma. We performed detailed analyses between cells from each condition to assess the effects of cryopreservation on cellular heterogeneity, cell quality, clustering and the identification of gene ontologies. In addition, we performed single-cell immunophenotyping using CITE-Seq on a single breast cancer sample cryopreserved as solid tissue fragments. RESULTS: Tumour heterogeneity identified from fresh tissues was largely conserved in cryopreserved replicates. We show that sequencing of single cells prepared from cryopreserved tissue fragments or from cryopreserved cell suspensions is comparable to sequenced cells prepared from fresh tissue, with cryopreserved cell suspensions displaying higher correlations with fresh tissue in gene expression. We showed that cryopreservation had minimal impacts on the results of downstream analyses such as biological pathway enrichment. For some tumours, cryopreservation modestly increased cell stress signatures compared to freshly analysed tissue. Further, we demonstrate the advantage of cryopreserving whole-cells for detecting cell-surface proteins using CITE-Seq, which is impossible using other preservation methods such as single nuclei-sequencing. CONCLUSIONS: We show that the viable cryopreservation of human cancers provides high-quality single-cells for multi-omics analysis. Our study guides new experimental designs for tissue biobanking for future clinical single-cell RNA sequencing studies.

Molecular Biomarkers for Contemporary Therapies in Hormone Receptor-Positive Breast Cancer.

Systemic treatment of hormone receptor-positive (HR+) breast cancer is undergoing a renaissance, with a number of targeted therapies including CDK4/6, mTOR, and PI3K inhibitors now approved for use in combination with endocrine therapies. The increased use of targeted therapies has changed the natural history of HR+ breast cancers, with the emergence of new escape mechanisms leading to the inevitable progression of disease in patients with advanced cancers. The identification of new predictive and pharmacodynamic biomarkers to current standard-of-care therapies and discovery of new therapies is an evolving and urgent clinical challenge in this setting. While traditional, routinely measured biomarkers such as estrogen receptors (ERs), progesterone receptors (PRs), and human epidermal growth factor receptor 2 (HER2) still represent the best prognostic and predictive biomarkers for HR+ breast cancer, a significant proportion of patients either do not respond to endocrine therapy or develop endocrine resistant disease. Genomic tests have emerged as a useful adjunct prognostication tool and guide the addition of chemotherapy to endocrine therapy. In the treatment-resistant setting, mutational profiling has been used to identify ESR1, PIK3CA, and AKT mutations as predictive molecular biomarkers to newer therapies. Additionally, pharmacodynamic biomarkers are being increasingly used and considered in the metastatic setting. In this review, we summarise the current state-of-the-art therapies; prognostic, predictive, and pharmacodynamic molecular biomarkers; and how these are impacted by emerging therapies for HR+ breast cancer.

Stromal cell diversity associated with immune evasion in human triple-negative breast cancer.

The tumour stroma regulates nearly all stages of carcinogenesis. Stromal heterogeneity in human triple-negative breast cancers (TNBCs) remains poorly understood, limiting the development of stromal-targeted therapies. Single-cell RNA sequencing of five TNBCs revealed two cancer-associated fibroblast (CAF) and two perivascular-like (PVL) subpopulations. CAFs clustered into two states: the first with features of myofibroblasts and the second characterised by high expression of growth factors and immunomodulatory molecules. PVL cells clustered into two states consistent with a differentiated and immature phenotype. We showed that these stromal states have distinct morphologies, spatial relationships and functional properties in regulating the extracellular matrix. Using cell signalling predictions, we provide evidence that stromal-immune crosstalk acts via a diverse array of immunoregulatory molecules. Importantly, the investigation of gene signatures from inflammatory-CAFs and differentiated-PVL cells in independent TNBC patient cohorts revealed strong associations with cytotoxic T-cell dysfunction and exclusion, respectively. Such insights present promising candidates to further investigate for new therapeutic strategies in the treatment of TNBCs.

MDM2 inhibition in combination with endocrine therapy and CDK4/6 inhibition for the treatment of ER-positive breast cancer.

BACKGROUND: Resistance to endocrine therapy is a major clinical challenge in the management of oestrogen receptor (ER)-positive breast cancer. In this setting, p53 is frequently wildtype and its activity may be suppressed via upregulation of its key regulator MDM2. This underlies our rationale to evaluate MDM2 inhibition as a therapeutic strategy in treatment-resistant ER-positive breast cancer. METHODS: We used the MDM2 inhibitor NVP-CGM097 to treat in vitro and in vivo models alone and in combination with fulvestrant or palbociclib. We perform cell viability, cell cycle, apoptosis and senescence assays to evaluate anti-tumour effects in p53 wildtype and p53 mutant ER-positive cell lines (MCF-7, ZR75-1, T-47D) and MCF-7 lines resistant to endocrine therapy and to CDK4/6 inhibition. We further assess the drug effects in patient-derived xenograft (PDX) models of endocrine-sensitive and endocrine-resistant ER-positive breast cancer. RESULTS: We demonstrate that MDM2 inhibition results in cell cycle arrest and increased apoptosis in p53-wildtype in vitro and in vivo breast cancer models, leading to potent anti-tumour activity. We find that endocrine therapy or CDK4/6 inhibition synergises with MDM2 inhibition but does not further enhance apoptosis. Instead, combination treatments result in profound regulation of cell cycle-related transcriptional programmes, with synergy achieved through increased antagonism of cell cycle progression. Combination therapy pushes cell lines resistant to fulvestrant or palbociclib to become senescent and significantly reduces tumour growth in a fulvestrant-resistant patient-derived xenograft model. CONCLUSIONS: We conclude that MDM2 inhibitors in combination with ER degraders or CDK4/6 inhibitors represent a rational strategy for treating advanced, endocrine-resistant ER-positive breast cancer, operating through synergistic activation of cell cycle co-regulatory programmes.

Window of opportunity treatment in breast cancer.

Window of opportunity therapies, which involve short-term administration of systemic therapy between cancer diagnosis and surgery, have raised significant interest in recent years as a mean of assessing the sensitivity of a patient's cancer to therapy prior to surgery. There is now compelling evidence that in patients with early stage hormone-receptor positive breast cancer, a 2-week preoperative treatment with standard hormone therapies in a preoperative window period provides important prognostic information, which in turn helps to aid decision-making regarding treatment options. Changes in short-term biomarker endpoints such as cell proliferation measured by Ki-67 can act as surrogate markers of long-term outcomes. Paired tissues obtained pre- and post-investigational treatment, without having to subject the patient to additional biopsies, can then be used to conduct translational research to investigate predictive biomarkers and pharmacodynamics. In this review, we will examine the utility and challenges of window of opportunities therapies in breast cancer in the current literature, and the current Australian and international trial landscape in this clinical space.

The International Academy of Cytology Yokohama System for Reporting Breast Fine-Needle Aspiration Biopsy Cytopathology.

The International Academy of Cytology (IAC) gathered together a group of cytopathologists expert in breast cytology who, working with clinicians expert in breast diagnostics and management, have developed the IAC Yokohama System for Reporting Breast Fine-Needle Aspiration Biopsy (FNAB) Cytology. The project was initiated with the first cytopathology group meeting in Yokohama at the 2016 International Congress of Cytology. This IAC Yokohama System defines five categories for reporting breast cytology, each with a clear descriptive term for the category, a definition, a risk of malignancy (ROM) and a suggested management algorithm. The key diagnostic cytopathology features of each of the lesions within each category will be presented more fully in a subsequent atlas. The System emphasizes that the crucial requirements for diagnostic breast FNAB cytology are a high standard for the performance of the FNAB and for the making of direct smears, and well-trained experienced cytopathologists to interpret the material. The performance indicators of breast FNAB, including specificity and sensitivity, negative predictive value, positive predictive value and ROM stated in this article have been derived from the recent literature. The current practice of breast FNAB has evolved with the increasing use of ultrasound guidance and rapid on-site evaluation. Two recent publications have shown a range of ROM for the insufficient/inadequate category of 2.6-4.8%, benign 1.4-2.3%, atypical 13-15.7%, suspicious of malignancy 84.6-97.1%, and malignant 99.0-100%. The management algorithm in the System provides options because there are variations in the management of breast lesions using FNAB and core-needle biopsy in those countries utilizing the "triple test" of clinical, imaging, and FNAB assessment, and also variations in the availability of CNB and imaging in low- and middle-income countries. The System will stimulate further discussion and research, particularly in the cytological diagnostic features of specific lesions within each category and in management recommendations. This will lead to continuing improvements in the care of patients with breast lesions and possible modifications to the IAC Yokohama System.

Non-canonical AR activity facilitates endocrine resistance in breast cancer.

The role of androgen receptor (AR) in endocrine-resistant breast cancer is controversial and clinical trials targeting AR with an AR antagonist (e.g., enzalutamide) have been initiated. Here, we investigated the consequence of AR antagonism using in vitro and in vivo models of endocrine resistance. AR antagonism in MCF7-derived tamoxifen-resistant (TamR) and long-term estrogen-deprived breast cancer cell lines were achieved using siRNA-mediated knockdown or pharmacological inhibition with enzalutamide. The efficacy of enzalutamide was further assessed in vivo in an estrogen-independent endocrine-resistant patient-derived xenograft (PDX) model. Knockdown of AR inhibited the growth of the endocrine-resistant cell line models. Microarray gene expression profiling of the TamR cells following AR knockdown revealed perturbations in proliferative signaling pathways upregulated in endocrine resistance. AR loss also increased some canonical ER signaling events and restored sensitivity of TamR cells to tamoxifen. In contrast, enzalutamide did not recapitulate the effect of AR knockdown in vitro, even though it inhibited canonical AR signaling, which suggests that it is the non-canonical AR activity that facilitated endocrine resistance. Enzalutamide had demonstrable efficacy in inhibiting AR activity in vivo but did not affect the growth of the endocrine-resistant PDX model. Our findings implicate non-canonical AR activity in facilitating an endocrine-resistant phenotype in breast cancer. Unlike canonical AR signaling which is inhibited by enzalutamide, non-canonical AR activity is not effectively antagonized by enzalutamide, and this has important implications in the design of future AR-targeted clinical trials in endocrine-resistant breast cancer.

Efficacy of harmonic focus scalpel in seroma prevention after axillary clearance.

INTRODUCTION: Seroma formation in breast cancer patients who have undergone axillary lymph node dissection (ALND) is a source of significant discomfort and morbidity. We aimed to ascertain seroma incidence after ALND, when Harmonic Focus (HF) scalpel is used for dissection instead of conventional diathermy (CD). METHODS(AND PATIENTS): This retrospective study was carried out in a single hospital over 6 years. Patients were allocated into HF group (HFG) or CD group (CDG). Seroma volume, hospital stay, and complications were evaluated. RESULTS: Of 94 patients, 42 were in the HFG and 52 in the CDG. Two day median seroma volume was 205 ml (IQR 95-265) for HF, and 227.5 ml (IQR 149-385) for CD. The total median seroma output was 270 ml (IQR 160-478) for HF, and 385 ml (IQR 220-558) for CD. No statistically significant differences between HFG and CDG were identified in these data, as well as patient demographics, operative time, and complication rates. Duration of surgery >2.5 h increased seroma formation (p < 0.001). Mastectomy and ALND increased seroma formation compared to wide local excision (WLE) and ALND (p < 0.05). Nodal involvement, number of lymph nodes resected, and extra nodal spread did not influence seroma formation. DISCUSSION(AND CONCLUSION): In our hands, HF use was not superior to CD in limiting seroma formation in ALND for breast cancer. Increased seroma formation in surgeries >2.5 h in duration is commensurate with surgeries involving mastectomy and ALND (>2.5 h in our study), which entails greater and sustained tissue and lymphovascular trauma.

Experience in dermomyofascial pouch coverage of immediate implants following skin sparing reduction mastectomy.

BACKGROUND: Mastectomy for breast cancer treatment and prophylaxis has improved survival for patients. The advantage of implant reconstruction post mastectomy is that it avoids an additional donor site with its associated morbidity, which post-mastectomy autologous reconstruction necessitates. However, the deficiency of muscle coverage at the lower pole of the implant meant it relied on only skin envelope coverage, and thus has the established complication of implant exposure or infection should the skin break down. In 2006, Nava devised a technique for a single-stage reconstruction using definitive breast implants with two-layer coverage of the lower pole with a vascularized dermal layer, as well as the traditional skin envelope, in women with preoperative large ptotic breasts. We present our experience with single-stage implant breast reconstruction using this technique. METHOD: A retrospective review of the medical and operative records as well as patients' photographs was undertaken for consecutive patients from November 2009 to April 2011. These patients were selected for the procedure based on set criteria. We describe our surgical technique for this procedure. RESULT: In the 18-month period, 6 patients underwent 11 skin sparing reduction mastectomy (SSRM) implant reconstructions. Follow-up ranged from 5 to 19 months. The mean length of hospital stay was 7.2 days (range was 2-15 days). One breast out of 11 reconstructions developed an infected seroma 8 months post-operatively, requiring aspiration and intravenous antibiotics. One breast out of 11 developed T junction skin necrosis and associated cellulitis but the breast implant was protected by a visibly vascularized dermal flap and, thus, was not exposed. One breast developed a minor vertical wound dehiscence. CONCLUSION: In our initial experience, SSRM is a safe and effective method of immediate implant-based breast reconstruction.

Retinoid signaling in pancreatic cancer, injury and regeneration.

BACKGROUND: Activation of embryonic signaling pathways quiescent in the adult pancreas is a feature of pancreatic cancer (PC). These discoveries have led to the development of novel inhibitors of pathways such as Notch and Hedgehog signaling that are currently in early phase clinical trials in the treatment of several cancer types. Retinoid signaling is also essential for pancreatic development, and retinoid therapy is used successfully in other malignancies such as leukemia, but little is known concerning retinoid signaling in PC. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the role of retinoid signaling in vitro and in vivo in normal pancreas, pancreatic injury, regeneration and cancer. Retinoid signaling is active in occasional cells in the adult pancreas but is markedly augmented throughout the parenchyma during injury and regeneration. Both chemically induced and genetically engineered mouse models of PC exhibit a lack of retinoid signaling activity compared to normal pancreas. As a consequence, we investigated Cellular Retinoid Binding Protein 1 (CRBP1), a key regulator of retinoid signaling known to play a role in breast cancer development, as a potential therapeutic target. Loss, or significant downregulation of CRBP1 was present in 70% of human PC, and was evident in the very earliest precursor lesions (PanIN-1A). However, in vitro gain and loss of function studies and CRBP1 knockout mice suggested that loss of CRBP1 expression alone was not sufficient to induce carcinogenesis or to alter PC sensitivity to retinoid based therapies. CONCLUSIONS/SIGNIFICANCE: In conclusion, retinoid signalling appears to play a role in pancreatic regeneration and carcinogenesis, but unlike breast cancer, it is not mediated directly by CRBP1.

Can breast MRI predict axillary lymph node metastasis in women undergoing neoadjuvant chemotherapy.

BACKGROUND: Axillary lymph node status provides important staging information. We sought to evaluate the predictive value of breast magnetic resonance imaging (MRI) in detecting axillary lymph node metastases prior to initiation of neoadjuvant chemotherapy (NAC) and in detecting residual lymph node metastases after NAC in women found to be node positive prior to NAC. METHODS: Women underwent breast MRI with axillary evaluation prior to initiation of NAC and again after completion of NAC. Pathologic confirmation of lymph node status was confirmed by sentinel lymph node biopsy (SLNB), image-guided axillary fine-needle aspiration (FNA)/core biopsy, or axillary lymph node dissection. We evaluated the sensitivity, specificity, and negative and positive predictive values of MRI in detecting axillary node involvement. RESULTS: Seventy-four women completed NAC and underwent surgery. Sensitivity of MRI in detecting axillary node involvement prior to NAC was 64.7% and specificity was 100%, with positive and negative predictive values of MRI of 100% and 77.8%, respectively. Sensitivity and specificity of MRI to identify residual pathologic axillary lymph node disease following NAC were 85.7% and 89%, respectively, while the positive and negative predictive values were 92% and 80.9%, respectively. CONCLUSION: Breast MRI has moderate sensitivity and high specificity for predicting axillary lymph node status prior to NAC. In patients found to be node positive prior to NAC, MRI was able to predict with moderate sensitivity and specificity whether residual nodal disease was present. The accuracy of MRI is not adequate to obviate either the need for staging by sentinel node biopsy or the need for completion axillary dissection in women determined to be node positive prior to NAC.

Loss of STARD10 expression identifies a group of poor prognosis breast cancers independent of HER2/Neu and triple negative status.

The phospholipid transfer protein STARD10 cooperates with c-erbB signaling and is overexpressed in Neu/ErbB2 breast cancers. We investigated if STARD10 expression provides additional prognostic information to HER2/neu status in primary breast cancer. A published gene expression dataset was used to determine relationships between STARD10 and HER2 mRNA levels and patient outcome. The central findings were independently validated by immunohistochemistry in a retrospective cohort of 222 patients with breast cancer with a median follow-up of 64 months. Kaplan-Meier and Cox proportional hazards analyses were used for univariate and multivariate analyses. Patients with low STARD10 or high HER2 tumor mRNA levels formed discrete groups each associated with a poor disease-specific survival (p = 0.0001 and p = 0.0058, respectively). In the immunohistochemical study low/absent STARD10 expression i.e. < or = 10% positive cells was observed in 24 of 222 (11%) tumors. In a univariate model, low/absent STARD10 expression was significantly associated with decreased patient survival (p = 0.0008). In multivariate analyses incorporating tumor size, tumor grade, lymph node status, ER, PR and HER2 status, low STARD10 expression was an independent predictor of death from breast cancer (HR: 2.56 (95% CI: 1.27-5.18), p = 0.0086). Furthermore, low/absent STARD10 expression, HER2 amplification and triple negative status were independent prognostic variables. Loss of STARD10 expression may provide an additional marker of poor outcome in breast cancer identifying a subgroup of patients with a particularly adverse prognosis, which is independent of HER2 amplification and the triple negative phenotype.

Androgen receptor inhibits estrogen receptor-alpha activity and is prognostic in breast cancer.

There is emerging evidence that the balance between estrogen receptor-alpha (ER(alpha)) and androgen receptor (AR) signaling is a critical determinant of growth in the normal and malignant breast. In this study, we assessed AR status in a cohort of 215 invasive ductal breast carcinomas. AR and (ER(alpha)) were coexpressed in the majority (80-90%) of breast tumor cells. Kaplan-Meier product limit analysis and multivariate Cox regression showed that AR is an independent prognostic factor in (ER(alpha))-positive disease, with a low level of AR (less than median of 75% positive cells) conferring a 4.6-fold increased risk of cancer-related death (P = 0.002). Consistent with a role for AR in breast cancer outcome, AR potently inhibited (ER(alpha))transactivation activity and 17beta-estradiol-stimulated growth of breast cancer cells. Transfection of MDA-MB-231 breast cancer cells with either functionally impaired AR variants or the DNA-binding domain of the AR indicated that the latter is both necessary and sufficient for inhibition of (ER(alpha)) signaling. Consistent with molecular modeling, electrophoretic mobility shift assays showed binding of the AR to an estrogen-responsive element (ERE). Evidence for a functional interaction of the AR with an ERE in vivo was provided by chromatin immunoprecipitation data, revealing recruitment of the AR to the progesterone receptor promoter in T-47D breast cancer cells. We conclude that, by binding to a subset of EREs, the AR can prevent activation of target genes that mediate the stimulatory effects of 17beta-estradiol on breast cancer cells.

Messina: a novel analysis tool to identify biologically relevant molecules in disease.

BACKGROUND: Morphologically similar cancers display heterogeneous patterns of molecular aberrations and follow substantially different clinical courses. This diversity has become the basis for the definition of molecular phenotypes, with significant implications for therapy. Microarray or proteomic expression profiling is conventionally employed to identify disease-associated genes, however, traditional approaches for the analysis of profiling experiments may miss molecular aberrations which define biologically relevant subtypes. METHODOLOGY/PRINCIPAL FINDINGS: Here we present Messina, a method that can identify those genes that only sometimes show aberrant expression in cancer. We demonstrate with simulated data that Messina is highly sensitive and specific when used to identify genes which are aberrantly expressed in only a proportion of cancers, and compare Messina to contemporary analysis techniques. We illustrate Messina by using it to detect the aberrant expression of a gene that may play an important role in pancreatic cancer. CONCLUSIONS/SIGNIFICANCE: Messina allows the detection of genes with profiles typical of markers of molecular subtype, and complements existing methods to assist the identification of such markers. Messina is applicable to any global expression profiling data, and to allow its easy application has been packaged into a freely-available stand-alone software package.

Expression of S100A2 calcium-binding protein predicts response to pancreatectomy for pancreatic cancer.

BACKGROUND & AIMS: Current methods of preoperative staging and predicting outcome following pancreatectomy for pancreatic cancer (PC) are inadequate. We evaluated the utility of multiple biomarkers from distinct biologic pathways as potential predictive markers of response to pancreatectomy and patient survival. METHODS: We assessed the relationship of candidate biomarkers known, or suspected, to be aberrantly expressed in PC, with disease-specific survival and response to therapy in a cohort of 601 patients. RESULTS: Of the 17 candidate biomarkers examined, only elevated expression of S100A2 was an independent predictor of survival in both the training (n = 162) and validation sets (n = 439; hazard ratio [HR], 2.19; 95% confidence interval [CI]: 1.48-3.25; P < .0001) when assessed in a multivariate model with clinical variables. Patients with high S100A2 expressing tumors had no survival benefit with pancreatectomy compared with those with locally advanced disease, whereas those without high S100A2 expression had a survival advantage of 10.6 months (19.4 vs 8.8 months, respectively) and a HR of 3.23 (95% CI: 2.39-4.33; P < .0001). Of significance, patients with S100A2-negative tumors had a significant survival benefit from pancreatectomy even in the presence of involved surgical margins (median, 15.7 months; P = .0007) or lymph node metastases (median, 17.4 months; P = .0002). CONCLUSIONS: S100A2 expression is a good predictor of response to pancreatectomy for PC and suggests that high S100A2 expression may be a marker of a metastatic phenotype. Prospective measurement of S100A2 expression in diagnostic biopsy samples has potential clinical utility as a predictive marker of response to pancreatectomy and other therapies that target locoregional disease.