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Rationale: Epigenetic mechanisms are fundamental processes that can modulate gene expression, allowing cellular adaptation to environmental conditions. Hypoxia is an important factor known to initiate the metastatic cascade in cancer, activating cell motility and invasion by silencing cell adhesion genes. G9a is a histone methyltransferase previously shown to accumulate in hypoxic conditions. While its oncogenic activity has been previously reported, not much is known about the role G9a plays in the hypoxia-mediated metastatic cascade. Methods: The role of G9a in cell motility in hypoxic condition was determined by inhibiting G9a either by short-hairpin mediated knock down or pharmacologically using a small molecule inhibitor. Through gene expression profiling, we identified CDH10 to be an important G9a target that regulates breast cancer cell motility. Lung metastasis assay in mice was used to determine the physiological significance of G9a. Results: We demonstrate that, while hypoxia enhances breast cancer migratory capacity, blocking G9a severely reduces cellular motility under both normoxic and hypoxic conditions and prevents the hypoxia-mediated induction of cellular movement. Moreover, inhibition of G9a histone methyltransferase activity in mice using a specific small molecule inhibitor significantly reduced growth and colonisation of breast cancer cells in the lung. We identify the type-II cadherin CDH10 as being a novel hypoxia-dependent gene, directly repressed by G9a through histone methylation. CDH10 overexpression significantly reduces cellular movements in breast cancer cell lines and prevents the hypoxia-mediated increase in cell motility. In addition, we show that CDH10 expression is prognostic in breast cancer and that it is inversely correlated to EHMT2 (G9a) transcript levels in many tumor-types, including breast cancer. Conclusion: We propose that G9a promotes cellular motility during hypoxic stress through the silencing of the cell adhesion molecule CDH10 and we describe CDH10 as a novel prognostic biomarker for breast cancer.

BackgroundIntratumoural heterogeneity is a poor prognostic feature in triple-negative breast cancer (TNBC) and other high-grade malignancies. It is caused by genomic instability and phenotypic plasticity, but how these features co-evolve during tumour development remains unclear. SOX10 is a transcription factor, neural crest stem cell (NCSC) specifier and candidate mediator of cancer-associated phenotypic plasticity.MethodsUsing immunophenotyping, we investigated the expression of SOX10 in normal human breast tissue and breast cancer (n=21 cosmetic breast reduction and 1,860 tumour samples with clinical annotation). We then defined the context and evolution of its expression in TNBC compared to 21 other malignancies using systems-level transcriptomics.ResultsSOX10 was detected in nuclei of normal mammary luminal progenitor cells, the histogenic origin of most TNBCs. In breast cancer, nuclear SOX10 predicted poor outcome amongst cross-sectional (log-rank p=0.0015, hazard ratio 2.02, n=224) and metaplastic (log-rank p=0.04, n=66) TNBCs. Systems-level transcriptional network analysis identified a core module in SOX10’s normal mammary epithelial transcription program that is rewired to NCSC genes in TNBC. Reprogramming was proportional to DNA damage and genome-wide promoter hypomethylation, particularly at CpG island shores. Using a novel network analysis pipeline, we found that NCSC-like transcriptional reprogramming is also strongly associated with promoter hypomethylation in other SOX10+ malignancies: glioma and melanoma.ConclusionsWe propose that cancer-associated genome hypomethylation simulates the open chromatin landscape of more primitive cell states, and that on this relatively unrestricted background, SOX10 recreates its ancestral gene regulatory circuits by default. These findings provide new insights about the basis of intratumoural heterogeneity and resurrection of developmental phenotypes in cancer; and highlight the potential for therapeutics that limit chromatin remodelling.

BackgroundThe nucleocytoplasmic shuttling of ERK5 has gained recent attention as a regulator of its diverse roles in cancer progression but the exact mechanisms for this shuttling are still under investigation.MethodsUsing in vitro, in vivo and in silico studies, we investigated the roles of shorter ERK5 isoforms in regulating the nucleocytoplasmic shuttling of active phosphorylated-ERK5 (pERK5). Retrospective cohorts of primary and metastatic breast cancer cases were used to evaluate the association of the subcellular localization of pERK5 with clinicopathological features.ResultsExtranuclear localization of pERK5 was observed during cell migration in vitro and at the invasive fronts of metastatic tumors in vivo. The nuclear and extranuclear cell fractions contained different isoforms of pERK5, which are encoded by splice variants expressed in breast and other cancers in the TCGA data. One isoform, isoform-3, lacks the C-terminal transcriptional domain and the nuclear localization signal. The co-expression of isoform-3 and full-length ERK5 associated with high epithelial-to-mesenchymal transition (EMT) and poor patient survival. Experimentally, expressing isoform-3 with full-length ERK5 in breast cancer cells increased cell migration, drove EMT and led to tamoxifen resistance. In breast cancer patient samples, pERK5 showed variable subcellular localizations where its extranuclear localization associated with aggressive clinicopathological features, metastasis, and poor survival.ConclusionOur studies support a model of ERK5 nucleocytoplasmic shuttling driven by splice variants in an interplay between mesenchymal and epithelial states during metastasis. Using ERK5 as a biomarker and a therapeutic target should account for its splicing and context-dependent biological functions.Graphical AbstractERK5 isoform-3 expression deploys active ERK5 (pERK5) outside the nucleus to facilitate EMT and cell migration. In cells dominantly expressing isoform-1, pERK5 shuttles to the nucleus to drive cell expansion.

Despite some improvement in the overall survival rates of breast cancer, it remains as a leading cause of cancer-related deaths in women. Currently, we are unable to accurately predict patients' response to therapies and their long-term outcome. We developed and patented a 275-gene signature based on in silico meta-analysis of global transcriptome profiles (approximately 10,000 cases) that can predict which patients suffer from aggressive disease and succumb to their disease within 5 years of diagnosis. This test, the integrated Breast Cancer Recurrence (iBCR) score outperformed every clinicopathological indicator available in three independent, large cohorts of breast cancer. The iBCR can also predict the likelihood of response to standard treatments and which emerging targeted therapies should be added to an individual's treatment regime to improve outcomes. In addition, 21 of the genes in this signature are novel potential drug targets that have not previously been described in aggressive breast tumours. We performed a pilot study using the NanoString nCounter Dx platform to measure the expression of the top 125 genes within the signature in a cohort of 48 patients. We have validated with 100% accuracy the prognostic power of the iBCR in the Queensland Follow Up (QFU) cohort with 25 years of follow up (p Citation Format: Kutasovic JR, Rozali E, Miranda M, Lakhani SR, Al-Ejeh F. The development of personalized diagnostic tests and therapeutic strategies in breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-47.

Anthracyclines are amongst the most effective chemotherapeutics ever developed, but they produce grueling side-effects, serious adverse events and resistance often develops over time. We found that these compounds can be sequestered by secreted cellular Prion protein (PrPC), blocking their cytotoxic activity. This effect was dose-dependent using either cell line-conditioned medium or human serum as a source of PrPC. Genetic depletion of PrPC or inhibition of binding via chelation of ionic copper prevented the interaction and restored cytotoxic activity. This was more pronounced for doxorubicin than its epimer, epirubicin. Investigating the relevance to breast cancer management, we found that the levels of PRNP transcript in pre-treatment tumor biopsies stratified relapse-free survival after neoadjuvant treatment with anthracyclines, particularly amongst doxorubicin-treated patients with residual disease at surgery (p=2.8E-08). These data suggest that local sequestration could mediate treatment resistance. Consistent with this, tumor cell expression of PrPC protein correlated with poorer response to doxorubicin but not epirubicin in an independent cohort analyzed by immunohistochemistry, particularly soluble isoforms released into the extracellular environment by shedding (p=0.015). These findings have important potential clinical implications for frontline regimen decision-making. We suggest there is warranted utility for prognostic PrPC/PRNP assays to guide chemo-sensitization strategies that exploit an understanding of PrPC-anthracycline-copper ion complexes.

The molecular rationale to induce synthetic lethality, by targeting defective homologous recombination repair in triple negative breast cancer (TNBC), has proven to have several shortcomings. Not meeting the expected minimal outcomes in clinical trials has highlighted common clinical resistance mechanisms including; increased expression of the target gene PARP1, increased expression or reversion mutation of BRCA1, or up-regulation of the compensatory homologous recombination protein RAD51. Indeed, RAD51 has been demonstrated to be an alternative synthetic lethal target in BRCA1-mutated cancers. To overcome selective pressure on DNA repair pathways, we examined new potential targets within TNBC that demonstrate synthetic lethality in association with RAD51 depletion. We confirmed complementary targets of PARP1/2 and DNA-PK as well as a new synthetic lethality combination with p38. p38 is considered a relevant target in breast cancer, as it has been implicated in resistance to chemotherapy, including tamoxifen. We show that the combination of targeting RAD51 and p38 inhibits cell proliferation both in vitro and in vivo, which was further enhanced by targeting of PARP1. Analysis of the molecular mechanisms revealed that depletion of RAD51 increased ERK1/2 and p38 signaling. Our results highlight a potential compensatory mechanism via p38 that limits DNA targeted therapy.

Cell lines are extremely useful tools in breast cancer research. Their key benefits include a high degree of control over experimental variables and reproducibility. However, the advantages must be balanced against the limitations of modelling such a complex disease in vitro. Informed selection of cell line(s) for a given experiment now requires essential knowledge about molecular and phenotypic context in the culture dish. We performed multidimensional profiling of 36 widely used breast cancer cell lines that were cultured under standardised conditions. Flow cytometry and digital immunohistochemistry were used to compare the expression of 14 classical breast cancer biomarkers related to intrinsic molecular profiles and differentiation states: EpCAM, CD24, CD49f, CD44, ER, AR, HER2, EGFR, E-cadherin, p53, vimentin, and cytokeratins 5, 8/18 and 19. This cell-by-cell analysis revealed striking heterogeneity within cultures of individual lines that would be otherwise obscured by analysing cell homogenates, particularly amongst the triple-negative lines. High levels of p53 protein, but not RNA, were associated with somatic mutations (p = 0.008). We also identified new subgroups using the nanoString PanCancer Pathways panel (730 transcripts representing 13 canonical cancer pathways). Unsupervised clustering identified five groups: luminal/HER2, immortalised (‘normal’), claudin-low and two basal clusters, distinguished mostly by baseline expression of TGF-beta and PI3-kinase pathway genes. These features are compared with other published genotype and phenotype information in a user-friendly reference table to help guide selection of the most appropriate models for in vitro and in vivo studies, and as a framework for classifying new patient-derived cancer cell lines and xenografts.

Triple-negative breast cancer (TNBC) is associated with poor survival. Chemotherapy is the only standard treatment for TNBC. The prevalence of BRCA1 inactivation in TNBC has rationalized clinical trials of poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors. Similarly, the overexpression of epidermal growth factor receptor (EGFR) rationalized anti-EGFR therapies in this disease. However, clinical trials using these 2 strategies have not reached their promise. In this study, we used EGFR as a target for radioimmunotherapy and hypothesized that EGFR-directed radioimmunotherapy can deliver a continuous lethal radiation dose to residual tumors that are radiosensitized by PARP inhibitors and chemotherapy. Methods:We analyzed EGFR messenger RNA in published gene expression array studies and investigated EGFR protein expression by immunohistochemistry in a cohort of breast cancer patients to confirm EGFR as a target in TNBC. Preclinically, using orthotopic and metastatic xenograft models of EGFR-positive TNBC,we investigated the effect of the novel combination of 177 Lu-labeled anti-EGFR monoclonal antibody, chemotherapy, and PARP inhibitors on cell death and the survival of breast cancer stem cells. Results: In this first preclinical study of anti-EGFR radioimmunotherapy in breast cancer, we found that anti-EGFR radioimmunotherapy is safe and that TNBC orthotopic tumors and established metastases were eradicated in mice treated with anti-EGFR radioimmunotherapy combined with chemotherapy and PARP inhibitors. We showed that the superior response to this triple-agent combination therapy was associated with apoptosis and eradication of putative breast cancer stem cells. Conclusion: Our data support further preclinical investigations toward the development of combination therapies using systemic anti-EGFR radioimmunotherapy for the treatment of recurrent and metastatic TNBC. Refereed/Peer-reviewed

Background: Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer with higher incidence of recurrence, more distant metastasis, and poorer survival. This subtype is also characterized by complex genomes where little of their genomes remain at normal copy number but without high, focal copy number amplifications. At the transciptome level, the majority of TNBC (∼75%) are classified as basal-like breast cancer (BLBC) according to the five intrinsic subtypes. Despite considerable genomic and gene expression characterization of TNBC, proteomic and phospho-proteomic investigations of this disease are limited with no available targeted therapies in clinical use. Methods & Results: We used the Kinex™ antibody array (http://www.kinexus.ca/) to interrogate protein/phosphoproteins levels in 43 primary breast cancer biopsies (16 TNBC, 16 ER/PR positive and 11 HER2-positive) and 16 breast cancer cell lines. Unsupervised hierarchical clustering of protein/phosphoprotein levels revealed two subgroups of TNBC in comparison to other subtypes. Western blotting and Proteome Profiler™ Arrays (R&D Systems) were used to validate deregulated proteins/phosphoproteins in TNBC. Pathway analysis revealed that one subgroup of TNBC exploits overlapping and cross-talking networks for survival. These signaling networks are downstream from elevated activation of EGFR, integrins and Insulin-like growth factor 1 receptor (IGF1R). Targeted molecular inhibitors of activated kinases in these pathways showed specificity against basal-like/TNBC cell lines compared to other subtypes in vitro. These activated kinases/networks represent druggable targets for the treatment of TNBC but may be limited by compensatory effect of the complex cross-talking signaling networks. To overcome compensatory downstream signaling that would limit the inhibition of a given pathway; we developed EGFR-targeted radioimmunotherapy (RIT) strategy to systemically deliver cytotoxic loads of beta particles (177Lu) that would kill targeted cells and surrounding cells by crossfire effect. The combination of EGFR-directed RIT with chemotherapy and PARP inhibition successfully treated orthotopic and metastatic TNBC models established from cell lines and patient-derived xenografts. The superior efficacy of this triple-agent combination therapy is explained by enhanced DNA damage and reduced DNA repair response, higher apoptotic cell death and the elimination of putative breast cancer stem cells. Conclusion: Proteomic analysis of TNBC provides a powerful tool to elucidate druggable signaling networks with therapeutic potential. TNBC utilizes complex interacting signaling networks and rational combination therapies are required for effective therapy. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-10-06.

Purpose: To develop effective combination therapy against pancreatic ductal adenocarcinoma (PDAC) with a combination of chemotherapy, CHK1 inhibition, and EGFR-targeted radioimmunotherapy. Experimental Design: Maximum tolerated doses were determined for the combination of gemcitabine, the CHK1 inhibitor PF-477736, and Lutetium-177 (177Lu)–labeled anti-EGFR antibody. This triple combination therapy was investigated using PDAC models from well-established cell lines, recently established patient-derived cell lines, and fresh patient-derived xenografts. Tumors were investigated for the accumulation of 177Lu-anti-EGFR antibody, survival of tumor-initiating cells, induction of DNA damage, cell death, and tumor tissue degeneration. Results: The combination of gemcitabine and CHK1 inhibitor PF-477736 with 177Lu-anti-EGFR antibody was tolerated in mice. This triplet was effective in established tumors and prevented the recurrence of PDAC in four cell line–derived and one patient-derived xenograft model. This exquisite response was associated with the loss of tumor-initiating cells as measured by flow cytometric analysis and secondary implantation of tumors from treated mice into treatment-naïve mice. Extensive DNA damage, apoptosis, and tumor degeneration were detected in the patient-derived xenograft. Mechanistically, we observed CDC25A stabilization as a result of CHK1 inhibition with consequent inhibition of gemcitabine-induced S-phase arrest as well as a decrease in canonical (ERK1/2 phosphorylation) and noncanonical EGFR signaling (RAD51 degradation) as a result of EGFR inhibition. Conclusions: Our study developed an effective combination therapy against PDAC that has potential in the treatment of PDAC. Clin Cancer Res; 20(12); 3187–97. ©2014 AACR.

Our understanding of breast cancer heterogeneity at the protein level is limited despite proteins being the ultimate effectors of cellular functions. We investigated the heterogeneity of breast cancer (41 primary tumors and 15 breast cancer cell lines) at the protein and phosphoprotein levels to identify activated oncogenic pathways and developing targeted therapeutic strategies. Heterogeneity was observed not only across histological subtypes, but also within subtypes. Tumors of the Triple negative breast cancer (TNBC) subtype distributed across four different clusters where one cluster (cluster ii) showed high deregulation of many proteins and phosphoproteins. The majority of TNBC cell lines, particularly mesenchymal lines, resembled the cluster ii TNBC tumors. Indeed, TNBC cell lines were more sensitive than non-TNBC cell lines when treated with targeted inhibitors selected based on upregulated pathways in cluster ii. In line with the enrichment of the upregulated pathways with onco-clients of Hsp90, we found synergy in combining Hsp90 inhibitors with several kinase inhibitors, particularly Erk5 inhibitors. The combination of Erk5 and Hsp90 inhibitors was effective in vitro and in vivo against TNBC leading to upregulation of pro-apoptotic effectors. Our studies contribute to proteomic profiling and improve our understanding of TNBC heterogeneity to provide therapeutic opportunities for this disease.

Colorectal cancers arising via the serrated pathway are often associated withBRAFV600E mutation, CpG island methylator phenotype (CIMP), and microsatellite instability. Previous studies have shown a strong association betweenBRAFV600E mutation and serrated polyps. This study aims to evaluate CIMP status of all the serrated polyp subtypes and its association with functionally important genes such asMLH1, p16,andIGFBP7. CIMP status and methylation were evaluated using the real-time based MethyLight assay in 154 serrated polyps and 63 conventional adenomas. Results showed that CIMP-high serrated polyps were strongly associated withBRAFmutation and proximal colon. CIMP-high was uncommon in conventional adenomas (1.59%), occurred in 8.25% of hyperplastic polyps (HPs), and became common in sessile serrated adenomas (SSAs) (51.43%).MLH1methylation was mainly observed in the proximal colon and was significantly associated withBRAFmutation and CIMP-high. The number of samples methylated forp16andIGFBP7was the highest in SSAs. The methylation panel we used to detect CIMP is highly specific for CIMP-high cancers. With this panel, we demonstrate that CIMP-high is much more common in SSAs than HPs. This suggests that CIMP-high correlates with increased risk of malignant transformation which was also observed in methylation of functionally important genes.

TNBC is a subtype of breast cancer known for its aggressive behavior and poor prognosis. TNBC accounts for 17-24% of all invasive breast cancers and is a subtype that lacks the expression of hormone receptors; oestrogen [ER], progesterone [PR]) and epidermal growth factor receptor 2 (HER2) receptors. Currently there has been a shift from using empirically derived agents that inhibit tumor cell growth and/or survival, to molecular therapies that target specific molecules that regulate these and other important biological processes. Despite the success of some new-targeted therapies to treat breast cancer, the outlook for the majority of patients with TNBC remains poor. Therefore we have utilized the KinexTM antibody array to resolve potential new targetable "nodes". We have screened 43 primary breast cancer biopsies (16 TNBC, 16 ER/PR positive and 11 HER2-positive) and 16 breast cancer cell lines for protein/phosphoprotein levels. Extracellular-signal-regulated kinase 5 (Erk5) is a member of the MAPK family. Erk5 has a large, unique C-terminal-half not found in other MAPK family members and because of this unique 400-amino acid extension, ERK5 is also called big MAP kinase 1 (BMK1). By extensive in silico analyses, we identified that the Erk5 metagene is prognostic and identifies TNBC/BLBC with poor prognosis. Our kinome study of primary breast cancer has further confirmed that the MEK5-Erk5 pathway is upregulated in the TNBC subgroup compared to the other TNBC subgroups and that pharmacological inhibition of Erk5 is therapeutic against primary MDA-MB-231 TNBC xenografts (1). Our preliminary data has shown that Erk5 is overexpressed in the TNBC subtype at the protein level. We have also shown that silencing Erk5 by siRNA or shRNA inhibits migration of TNBC cell lines in vitro. Expression of Erk5 (total and phosphoproteins) will be investigated in primary breast tumours and metastases samples from patient by immunohistochemistry. We will also overexpress Erk5 in non-metastatic breast cancer cell lines to study the effect of Erk5 overexpression on metastases. In an elegant study, site directed mutagenesis was used to modify Erk5 and show that phosphorylations of the C-terminal domain of kinase activated Erk5 is required for the transcriptional activity of Erk5. Using in vitro and in vivo models we will determine if the transcriptional activity of activated Erk5 is a major player to drive metastatic phenotype. Moreover, whether kinase-dependent or transcription-dependent activity of Erk5 on several pathways is sufficient to drive metastasis will also be determined. Our results strongly suggest the MEK5-Erk5 pathway as a prognostic and therapeutic pathway in a poor-prognosis subset of TNBC/BCLC. Characterization of this pathway in clinical cohorts particularly in TNBC tumors, mechanistic understanding of its contribution to metastasis and therapeutic targeting in vivo would help develop a personalised approach to identify and treat TNBC tumors and metastases with activated Erk5 pathway. 1. Al-Ejeh F, Miranda M et al. Kinome profiling reveals breast cancer heterogeneity and identifies targeted therapeutic opportunities for triple negative breast cancer. Oncotarget. March 19, 2014. Citation Format: Mariska Sauzine Miranda, Fares Al Ejeh, Wei Shi, Peter Simpson, Sunil Lakhani, Kum Kum Khanna. Erk5 as a therapeutic target in triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-03-11.

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype lacking expression of estrogen and progesterone receptors (ER/PR) and HER2, thus limiting therapy options. We hypothesized that meta-analysis of TNBC gene expression profiles would illuminate mechanisms underlying the aggressive nature of this disease and identify therapeutic targets. Meta-analysis in the Oncomine database identified 206 genes that were recurrently deregulated in TNBC compared with non-TNBC and in tumors that metastasized or led to death within 5 years. This ‘aggressiveness gene list' was enriched for two core functions/metagenes: chromosomal instability (CIN) and ER signaling metagenes. We calculated an ‘aggressiveness score' as the ratio of the CIN metagene to the ER metagene, which identified aggressive tumors in breast cancer data sets regardless of subtype or other clinico-pathological indicators. A score calculated from six genes from the CIN metagene and two genes from the ER metagene recapitulated the aggressiveness score. By multivariate survival analysis, we show that our aggressiveness scores (from 206 genes or the 8 representative genes) outperformed several published prognostic signatures. Small interfering RNA screen revealed that the CIN metagene holds therapeutic targets against TNBC. Particularly, the inhibition of TTK significantly reduced the survival of TNBC cells and synergized with docetaxel in vitro. Importantly, mitosis-independent expression of TTK protein was associated with aggressive subgroups, poor survival and further stratified outcome within grade 3, lymph node-positive, HER2-positive and TNBC patients. In conclusion, we identified the core components of CIN and ER metagenes that identify aggressive breast tumors and have therapeutic potential in TNBC and aggressive breast tumors. Prognostication from these metagenes at the mRNA level was limited to ER-positive tumors. However, we provide evidence that mitosis-independent expression of TTK protein was prognostic in TNBC and other aggressive breast cancer subgroups, suggesting that protection of CIN/aneuploidy drives aggressiveness and treatment resistance.

Serrated polyps are now recognized as the precursor lesion from which sporadic BRAF (V600E) mutant/CIMP-H colorectal cancers (CRC) develop, but it appears likely BRAF mutation alone is not enough to drive progression to carcinoma. CIMP is generally localized to the proximal colon and may cause the epigenetic silencing of key genes such as IGFBP7 that may act in concert with BRAF mutation to promote neoplasia. We are conducting a detailed molecular analysis of the mechanism of serrated neoplasia involving IGFBP7 and evasion of oncogene-induced senescence (OIS). Normally senescence functions as a defense mechanism against tumorigenesis in precursor lesions. We have analysed 44 CRCs and 217 colorectal polyps including 45 advanced serrated polyps (sessile serrated adenomas, serrated adenomas and mixed polyps) and 109 simple serrated polyps (goblet cell rich hyperplastic polyps and microvesicular hyperplastic polyps) for BRAF, K-ras and CIMP relative to clinicopathologic variables. In addition a MethyLight assay was developed to determine IGFBP7 methylation patterns in serrated polyps and cancers. For serrated polyps, both BRAF mutation (75.5%) and CIMP (46.6%) was most frequent in advanced serrated polyps (ASPs). Overall the frequency of CIMP was significantly associated with proximal location (P Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-15.

The MEK5-ERK5 pathway is a mammalian mitogen-activated protein (MAP) kinase cascade that is not well studied compared to other MAP kinase cascades. Two independent studies by Al-Ejeh et al. and Ortiz-Ruiz et al. published in Oncotarget last year concluded that ERK5 is an attractive target in triple negative breast cancer. In this perspective, we briefly describe the findings of these studies and propose the use of pharmacological inhibition of ERK5 in combination with chemotherapy against triple negative breast cancer because MEK5-ERK5 overexpression associates with poor survival of patients treated with chemotherapy.