Vaccines targeting ESR1 activating mutations elicit anti-tumor immune responses and suppress estrogen signaling in therapy resistant ER+ breast cancer.

ER+ breast cancers (BC) are characterized by the elevated expression and signaling of estrogen receptor alpha (ESR1), which renders them sensitive to anti-endocrine therapy. While these therapies are clinically effective, prolonged treatment inevitably results in therapeutic resistance, which can occur through the emergence of gain-of-function mutations in ESR1. The central importance of ESR1 and development of mutated forms of ESR1 suggest that vaccines targeting these proteins could potentially be effective in preventing or treating endocrine resistance. To explore the potential of this approach, we developed several recombinant vaccines encoding different mutant forms of ESR1 (ESR1mut) and validated their ability to elicit ESR1-specific T cell responses. We then developed novel ESR1mut-expressing murine mammary cancer models to test the anti-tumor potential of ESR1mut vaccines. We found that these vaccines could suppress tumor growth, ESR1mut expression and estrogen signaling in vivo. To illustrate the applicability of these findings, we utilize HPLC to demonstrate the presentation of ESR1 and ESR1mut peptides on human ER+ BC cell MHC complexes. We then show the presence of human T cells reactive to ESR1mut epitopes in an ER+ BC patient. These findings support the development of ESR1mut vaccines, which we are testing in a Phase I clinical trial.

CEA vaccines.

Carcinoembryonic antigen (CEA) is a glycosylated cell surface oncofetal protein involved in adhesion, proliferation, and migration that is highly upregulated in multiple carcinomas and has long been a promising target for cancer vaccination. This review summarizes the progress to date in the development of CEA vaccines, examining both pre-clinical and clinical studies across a variety of vaccine platforms that in aggregate, begin to reveal some critical insights. These studies demonstrate the ability of CEA vaccines to break immunologic tolerance and elicit CEA-specific immunity, which associates with improved clinical outcomes in select individuals. Approaches that have combined replicating viral vectors, with heterologous boosting and different adjuvant strategies have been particularly promising but, these early clinical trial results will require confirmatory studies. Collectively, these studies suggest that clinical efficacy likely depends upon harnessing a potent vaccine combination in an appropriate clinical setting to fully realize the potential of CEA vaccination.

Gene expression signatures of individual ductal carcinoma in situ lesions identify processes and biomarkers associated with progression towards invasive ductal carcinoma.

Ductal carcinoma in situ (DCIS) is considered a non-invasive precursor to breast cancer, and although associated with an increased risk of developing invasive disease, many women with DCIS will never progress beyond their in situ diagnosis. The path from normal duct to invasive ductal carcinoma (IDC) is not well understood, and efforts to do so are hampered by the substantial heterogeneity that exists between patients, and even within patients. Here we show gene expression analysis from > 2,000 individually micro-dissected ductal lesions representing 145 patients. Combining all samples into one continuous trajectory we show there is a progressive loss in basal layer integrity heading towards IDC, coupled with two epithelial to mesenchymal transitions, one early and a second coinciding with the convergence of DCIS and IDC expression profiles. We identify early processes and potential biomarkers, including CAMK2N1, MNX1, ADCY5, HOXC11 and ANKRD22, whose reduced expression is associated with the progression of DCIS to invasive breast cancer.

Stimulation of Oncogene-Specific Tumor-Infiltrating T Cells through Combined Vaccine and αPD-1 Enable Sustained Antitumor Responses against Established HER2 Breast Cancer.

PURPOSE: Despite promising advances in breast cancer immunotherapy, augmenting T-cell infiltration has remained a significant challenge. Although neither individual vaccines nor immune checkpoint blockade (ICB) have had broad success as monotherapies, we hypothesized that targeted vaccination against an oncogenic driver in combination with ICB could direct and enable antitumor immunity in advanced cancers. EXPERIMENTAL DESIGN: Our models of HER2+ breast cancer exhibit molecular signatures that are reflective of advanced human HER2+ breast cancer, with a small numbers of neoepitopes and elevated immunosuppressive markers. Using these, we vaccinated against the oncogenic HER2Δ16 isoform, a nondriver tumor-associated gene (GFP), and specific neoepitopes. We further tested the effect of vaccination or anti-PD-1, alone and in combination. RESULTS: We found that only vaccination targeting HER2Δ16, a driver of oncogenicity and HER2-therapeutic resistance, could elicit significant antitumor responses, while vaccines targeting a nondriver tumor-specific antigen or tumor neoepitopes did not. Vaccine-induced HER2-specific CD8+ T cells were essential for responses, which were more effective early in tumor development. Long-term tumor control of advanced cancers occurred only when HER2Δ16 vaccination was combined with αPD-1. Single-cell RNA sequencing of tumor-infiltrating T cells revealed that while vaccination expanded CD8 T cells, only the combination of vaccine with αPD-1 induced functional gene expression signatures in those CD8 T cells. Furthermore, we show that expanded clones are HER2-reactive, conclusively demonstrating the efficacy of this vaccination strategy in targeting HER2. CONCLUSIONS: Combining oncogenic driver targeted vaccines with selective ICB offers a rational paradigm for precision immunotherapy, which we are clinically evaluating in a phase II trial (NCT03632941).

Patterns of clinicopathological features and outcome in epithelial ovarian cancer patients: 35 years of prospectively collected data.

OBJECTIVE: Investigate the clinical landscape of ovarian carcinoma (OC) over time. DESIGN: Register-based prospectively collected data. SETTING: South East Scotland. SAMPLE: A total of 2805 OC patients diagnosed in 1981-2015. METHODS: Survival times were visualised using the Kaplan-Meier method; median survival, 5-year survival probabilities and associated restricted mean survival time analyses were used to quantify survival differences. MAIN OUTCOME MEASURES: Disease-specific survival. RESULTS: A significant increase in disease-specific survival (DSS) from 1981-1985 to 2011-2015 was observed (median 1.73 versus 4.23 years, P < 0.0001). Corresponding increase in progression-free survival (PFS) was not statistically significant (median 1.22 versus 1.58 years, P = 0.2568). An increase in the proportion of cases with low residual disease volume (RD) (<2 cm RD) following debulking was observed (54.0% versus 87.7%, P < 0.0001). The proportion of high grade serous (HGS) cases increased (P < 0.0001), whereas endometrioid and mucinous cases decreased (P = 0.0005 and P = 0.0002). Increases in stage IV HGS OC incidence (P = 0.0009) and stage IV HGS OC DSS (P = 0.0122) were observed. Increasing median age at diagnosis correlated with increasing Eastern Cooperative Oncology Group Performance Status (ECOG PS) over time (r = 0.86). CONCLUSIONS: OC DSS has improved over the last 35 years. PFS has not significantly increased, highlighting that improvement in outcome has been limited to extending post-relapse survival. Distribution of stage at diagnosis, histological subtype and RD following debulking has changed over time, reflecting evolution in tumour classification, staging and optimal debulking definitions (from low RD to minimal or zero RD). Histology, stage, RD and ECOG PS remain reliable outcome predictors. Increasing median age at diagnosis and ECOG PS indicates demographic shifts in the clinical population. TWEETABLE ABSTRACT: Significant improvement in ovarian carcinoma survival has been seen over time. Most of this improvement is due to an extension of survival following disease relapse.

Predictive significance of T cell subset changes during ex vivo generation of adoptive cellular therapy products for the treatment of advanced non-small cell lung cancer.

Adoptive T cell immunotherapy with cytokine-induced killer cells (CIKs) has been demonstrated to prolong the survival of patients with advanced non-small cell lung cancer (NSCLC). The aim of the present study was to evaluate whether the expansion of effector T cells and the decrease of regulatory T cells (Tregs) that occurred during the ex vivo generation of DC-CIKs were associated with improved clinical outcome in patients who received treatment. CIKs were generated ex vivo over a 28-day period from the peripheral blood apheresis product of 163 patients with advanced cancer (including 30 with NSCLC). CIKs were also generated from an additional cohort of 65 patients with NSCLC over a 15-day period. The progression-free survival (PFS) and overall survival (OS) time of patients treated with CIKs was determined by reviewing the patients' medical records. The number of CIKs gradually increased during the culture period and peaked at day 15, followed by a slight decline until day 28. Similarly, the percentages of T cell subtypes associated with anti-tumor activity (CD3+, CD3+CD4+, CD3+CD8+ and CD8+CD28+) peaked at day 15. Although the percentage of CD4+CD25+CD127+ Tregs increased by day 7, a decrease was subsequently observed. Among the 95 patients with NSCLC, those with a post/pre-culture ratio of CD8+CD28+ T lymphocytes >2.2 had significantly better PFS and OS compared with those with ratios ≤2.2. Those with a post/pre-culture CD4+CD25+CD127+ Treg ratio ≤0.6 had significantly better OS and PFS compared with those with ratios >0.6. The peak expansion of CIKs from peripheral blood mononuclear cells occurred at day 15 of ex vivo culture. PFS and OS were associated with post/pre-culture CD8+CD28+ T lymphocyte ratio >2.2 and post/pre-culture CD4+CD25+CD127+ Treg ratio <0.6 in the CIKs of patients with advanced NSCLC treated with adoptive T cell immunotherapy. Further efforts are underway to optimize the DC-CIK infusion for cancer immunotherapy.

Paradoxical upgrading reaction in extra-pulmonary tuberculosis: association with vitamin D therapy.

SETTING: Glasgow, Scotland, UK. BACKGROUND: Paradoxical reactions in tuberculosis (TB) are a notable example of our incomplete understanding of host-pathogen interactions during anti-tuberculosis treatment. OBJECTIVES: To determine risk factors for a TB paradoxical reaction, and specifically to assess for an independent association with vitamin D use. DESIGN: Consecutive human immunodeficiency virus (HIV) negative adult patients treated for extra-pulmonary TB were identified from an Extended Surveillance of Mycobacterial Infections database. In our setting, vitamin D was variably prescribed for newly diagnosed TB patients. A previously published definition of paradoxical TB reaction was retrospectively applied to, and data on all previously described risk factors were extracted from, centralised electronic patient records. The association with vitamin D use was assessed using multivariate logistic regression. RESULTS: Of the 249 patients included, most had TB adenopathy; 222/249 had microbiologically and/or histologically confirmed TB. Vitamin D was prescribed for 57/249 (23%) patients; 37/249 (15%) were classified as having paradoxical reactions. Younger age, acid-fast bacilli-positive invasive samples, multiple disease sites, lower lymphocyte count and vitamin D use were found to be independent risk factors. CONCLUSION: We speculate that vitamin D-mediated signalling of pro-inflammatory innate immune cells, along with high antigenic load, may mediate paradoxical reactions in anti-tuberculosis treatment.

A multicentre retrospective comparison of central nervous system prophylaxis strategies among patients with high-risk diffuse large B-cell lymphoma.

BACKGROUND: Central nervous system (CNS) relapse in diffuse large B-cell lymphoma (DLBCL) is a devastating complication; the optimal prophylactic strategy remains unclear. METHODS: We performed a multicentre, retrospective analysis of patients with DLBCL with high risk for CNS relapse as defined by two or more of: multiple extranodal sites, elevated serum LDH and B symptoms or involvement of specific high-risk anatomical sites. We compared three different strategies of CNS-directed therapy: intrathecal (IT) methotrexate (MTX) with (R)-CHOP 'group 1'; R-CHOP with IT MTX and two cycles of high-dose intravenous (IV) MTX 'group 2'; dose-intensive systemic antimetabolite-containing chemotherapy (Hyper-CVAD or CODOXM/IVAC) with IT/IV MTX 'group 3'. RESULTS: Overall, 217 patients were identified (49, 125 and 43 in groups 1-3, respectively). With median follow-up of 3.4 (range 0.2-18.6) years, 23 CNS relapses occurred (12, 10 and 1 in groups 1-3 respectively). The 3-year actuarial rates (95% CI) of CNS relapse were 18.4% (9.5-33.1%), 6.9% (3.5-13.4%) and 2.3% (0.4-15.4%) in groups 1-3, respectively (P=0.009). CONCLUSIONS: The addition of high-dose IV MTX and/or cytarabine was associated with lower incidence of CNS relapse compared with IT chemotherapy alone. However, these data are limited by their retrospective nature and warrant confirmation in prospective randomised studies.

Plerixafor plus pegfilgrastim is a safe, effective mobilization regimen for poor or adequate mobilizers of hematopoietic stem and progenitor cells: a phase I clinical trial.

The safety, kinetics and efficacy of plerixafor+pegfilgrastim for hematopoietic stem and progenitor cell (HSPC) mobilization are poorly understood. We treated 12 study patients (SP; lymphoma n=10 or myeloma n=2) with pegfilgrastim (6 mg SC stat D1) and plerixafor (0.24 mg/kg SC nocte from D3). Six SP were 'predicted poor-mobilizers' and six were 'predicted adequate-mobilizers'. Peripheral blood (PB) CD34(+) monitoring commenced on D3. Apheresis commenced on D4. Comparison was with 22 historical controls (HC; lymphoma n=18, myeloma n=4; poor mobilizers n=4), mobilized with pegfilgrastim alone. Eight (67%) SP had PB CD34(+) count ⩽5 × 10(6)/L D3 post pegfilgrastim; all SP surpassed this threshold the morning after plerixafor. In SP, PBCD34(+) counts peaked D4 6/12 (50%), remaining ⩾5 × 10(6)/L for 4 days in 8/12 (67%). All SP successfully yielded target cell numbers (⩾2 × 10(6)/kg) within four aphereses. After maximum four aphereses, median total CD34+ yield was higher in SP than HC; 8.0 (range 2.4-12.9) vs 4.8 (0.4-14.0) × 10(6)/kg (P=0.04). Seven of twelve (58%) SP achieved target yield after one apheresis. Flow cytometry revealed no tumor cells in PB or apheresis product of SP. Plerixafor+pegfilgrastim was well tolerated with bone pain (n=2), diarrhoea (n=2) and facial paraesthesiae (n=3). Plerixafor+pegfilgrastim is a simple, safe and effective HSPC mobilization regimen in myeloma and lymphoma, in both poor and good mobilizers, and is superior to pegfilgrastim alone.

Limited role for surveillance PET-CT scanning in patients with diffuse large B-cell lymphoma in complete metabolic remission following primary therapy.

BACKGROUND: The usefulness of positron emission tomography with computed tomography (PET-CT) in the surveillance of patients with diffuse large B-cell lymphoma (DLBCL) in complete metabolic remission after primary therapy is not well studied. METHODS: We performed a retrospective review of our database between 2002 and 2009 for patients with de novo DLBCL who underwent surveillance PET-CT after achieving complete metabolic response (CMR) following primary therapy. RESULTS: Four-hundred and fifty scans were performed in 116 patients, with a median follow-up of 53 (range 8-133) months from completion of therapy. Thirteen patients (11%) relapsed: seven were suspected clinically and six were subclinical (all within first 18 months). The positive predictive value in patients with international prognostic index (IPI) <3 was 56% compared with 80% in patients with IPI ≥3. Including indeterminate scans, PET-CT retained high sensitivity 95% and specificity 97% for relapse. CONCLUSION: Positron emission tomography with computed tomography is not useful in patients for the majority of patients with diffuse large B-cell lymphoma in CMR after primary therapy, with the possible exception of patients with baseline IPI ≥3 in the 18 months following completion of primary therapy. This issue could be addressed by a prospective clinical trial.

Management of locally advanced renal cell carcinoma with invasion of the duodenum.

Renal cell carcinoma (RCC) is rare but aggressive, with greater than 20% of patients presenting with stage III or IV, disease. Surgical resection of the primary tumor regardless of stage is the treatment of choice, and en bloc resection of involved organs provides the only potential chance for cure. This case report describes a patient with metastatic right-sided RCC with invasion of the inferior vena cava and duodenum managed by en block resection and pancreaticoduodenectomy. This report will review the workup and treatment of locally advanced RCC, as well as the role of cytoreductive nephrectomy in the setting of metastatic disease.

Pegfilgrastim compared with filgrastim for cytokine-alone mobilization of autologous haematopoietic stem and progenitor cells.

Haematopoietic stem and progenitor cells (HSPC) mobilization, using cytokine-alone, is a well-tolerated regimen with predictable mobilization kinetics. Single-dose pegfilgrastim mobilizes HSPC efficiently; however, there is surprisingly little comparative data on its use without chemotherapy for HSPC mobilization. Pegfilgrastim-alone and filgrastim-alone mobilization regimens were compared in 52 patients with haematological malignancy. Pegfilgrastim 12 mg (n=20) or 6 mg (n=2) was administered Day 1 (D1) in 22 patients (lymphoma n=17; myeloma n=5). Thirty historical controls (lymphoma n=18; myeloma n=12) received filgrastim 10 mcg/kg daily from D1. Peripheral blood (PB) CD34(+) counts reached threshold (5 × 10(6)/L) and apheresis commenced on D4(4-5) and D4(4-6). Median PB CD34(+) cell count on D1 of apheresis was similar (26.0 × 10(6)/L (2.5-125.0 × 10(6)/L) and 16.2 × 10(6)/L (2.6-50.7 × 10(6)/L); P=0.06), for pegfilgrastim and filgrastim groups, respectively. Target yield (2 × 10(6) per kg CD34(+) cells) was collected in 20/22 (91%) pegfilgrastim patients and 24/30 (80%) in the filgrastim group (P=0.44), in a similar median number of aphereses (3(1-4) versus 3(2-6), respectively; P=0.85). A higher proportion of pegfilgrastim patients tended to yield 4 × 10(6) per kg CD34(+) cells; 16/22 (73%) versus 14/30 (47%) filgrastim patients (P=0.09). One pegfilgrastim patient developed hyperleukocytosis that resolved without incident. Pegfilgrastim-alone is a simple, well-tolerated, and attractive option for outpatient-based HSPC mobilization with similar mobilization kinetics and efficacy to regular filgrastim.

Disease specific biomarkers of abdominal aortic aneurysms detected by surface enhanced laser desorption ionization time of flight mass spectrometry.

INTRODUCTION: Biomarkers have the potential to improve the clinical management of patients with AAA. REPORT: A prospective, proteomics discovery study was undertaken to compare patients with AAA (n = 20) to matched screened controls (n = 19) for plasma protein expression. Surface-Enhanced-Laser-Desorption-Ionization Time of Flight Mass Spectrometry (SELDI ToF MS) coupled with Artificial Neural Networks (ANN) analysis identified six protein related diagnostic biomarker ions with a combined AUC of 0.89. DISCUSSION: This study discovered a signature plasma protein profile for patients with AAA and demonstrated that mass spectrometric based research for disease specific biomarker of AAA is feasible.

Increasing vaccine potency through exosome antigen targeting.

While many tumor associated antigens (TAAs) have been identified in human cancers, efforts to develop efficient TAA "cancer vaccines" using classical vaccine approaches have been largely ineffective. Recently, a process to specifically target proteins to exosomes has been established which takes advantage of the ability of the factor V like C1C2 domain of lactadherin to specifically address proteins to exosomes. Using this approach, we hypothesized that TAAs could be targeted to exosomes to potentially increase their immunogenicity, as exosomes have been demonstrated to traffic to antigen presenting cells (APC). To investigate this possibility, we created adenoviral vectors expressing the extracellular domain (ECD) of two non-mutated TAAs often found in tumors of cancer patients, carcinoembryonic antigen (CEA) and HER2, and coupled them to the C1C2 domain of lactadherin. We found that these C1C2 fusion proteins had enhanced expression in exosomes in vitro. We saw significant improvement in antigen specific immune responses to each of these antigens in naïve and tolerant transgenic animal models and could further demonstrate significantly enhanced therapeutic anti-tumor effects in a human HER2+ transgenic animal model. These findings demonstrate that the mode of secretion and trafficking can influence the immunogenicity of different human TAAs, and may explain the lack of immunogenicity of non-mutated TAAs found in cancer patients. They suggest that exosomal targeting could enhance future anti-tumor vaccination protocols. This targeting exosome process could also be adapted for the development of more potent vaccines in some viral and parasitic diseases where the classical vaccine approach has demonstrated limitations.

Prediction of residues involved in inhibitor specificity in the dihydrofolate reductase family.

Dihydrofolate reductase (DHFR) is of significant recent interest as a target for drugs against parasitic and opportunistic infections. Understanding factors which influence DHFR homolog inhibitor specificity is critical for the design of compounds that selectively target DHFRs from pathogenic organisms over the human homolog. This paper presents a novel approach for predicting residues involved in ligand discrimination in a protein family using DHFR as a model system. In this approach, the relationship between inhibitor specificity and amino acid composition for sets of protein homolog pairs is examined. Similar inhibitor specificity profiles correlate with increased sequence homology at specific alignment positions. Residue positions that exhibit the strongest correlations are predicted as specificity determinants. Correlation analysis requires a quantitative measure of similarity in inhibitor specificity (S(lig)) for a pair of homologs. To this end, a method of calculating S(lig) values using K(I) values for the two homologs against a set of inhibitors as input was developed. Correlation analysis of S(lig) values to amino acid sequence similarity scores - obtained via multiple sequence alignments - was performed for individual residue alignment positions and sets of residues on 13 DHFRs. Eighteen alignment positions were identified with a strong correlation of S(lig) to sequence similarity. Of these, three lie in the active site; four are located proximal to the active site, four are clustered together in the adenosine binding domain and five on the ßFßG loop. The validity of the method is supported by agreement between experimental findings and current predictions involving active site residues.

How we mobilize haemopoietic stem cells.

Mobilization and collection of haemopoietic stem and progenitor cells (HSPC) is the cornerstone of autologous and allogeneic stem cell transplantation for a wide variety of haematological and some non-haematological malignancies. Centres providing this service face the challenge of optimizing the likelihood of successful collection of transplantable doses of cells, while maximizing the efficiency of the apheresis unit and minimizing the risk of toxicity as well as mobilization failure. Recent developments in the understanding of the molecular mechanisms of mobilization have led to the emergence of novel strategies for HSPC mobilization, which may assist in meeting these imperatives. The task for clinicians is how to incorporate the use of these strategies into practice, in the light of emerging evidence for efficacy and safety of these agents. Herein, the literature is reviewed, and a proposed algorithm for HSPC mobilization is presented.

Truncated ErbB2 expressed in tumor cell nuclei contributes to acquired therapeutic resistance to ErbB2 kinase inhibitors.

ErbB2 tyrosine kinase inhibitors (TKI) block tyrosine autophosphorylation and activation of the full-length transmembrane ErbB2 receptor (p185(ErbB2)). In addition to p185(ErbB2), truncated forms of ErbB2 exist in breast cancer cell lines and clinical tumors. The contribution of these truncated forms, specifically those expressed in tumor cell nuclei, to the development of therapeutic resistance to ErbB2 TKIs has not been previously shown. Here, we show that expression of a 95-kDa tyrosine phosphorylated form of ErbB2, herein referred to as p95L (lapatinib-induced p95) was increased in ErbB2(+) breast cancer cells treated with potent ErbB2 TKIs (lapatinib, GW2974). Expressed in tumor cell nuclei, tyrosine phosphorylation of p95L was resistant to inhibition by ErbB2 TKIs. Furthermore, the expression of p95L was increased in ErbB2(+) breast cancer models of acquired therapeutic resistance to lapatinib that mimic the clinical setting. Pretreatment with proteasome inhibitors blocked p95L induction in response to ErbB2 TKIs, implicating the role of the proteasome in the regulation of p95L expression. In addition, tyrosine phosphorylated C-terminal fragments of ErbB2, generated by alternate initiation of translation and similar in molecular weight to p95L, were expressed in tumor cell nuclei, where they too were resistant to inhibition by ErbB2 TKIs. When expressed in the nuclei of lapatinib-sensitive ErbB2(+) breast cancer cells, truncated ErbB2 rendered cells resistant to lapatinib-induced apoptosis. Elucidating the function of nuclear, truncated forms of ErbB2, and developing therapeutic strategies to block their expression and/or activation may enhance the clinical efficacy of ErbB2 TKIs.

HER2 overexpression elicits a proinflammatory IL-6 autocrine signaling loop that is critical for tumorigenesis.

HER2 overexpression occurs in approximately 25% of breast cancers, where it correlates with poor prognosis. Likewise, systemic inflammation in breast cancer correlates with poor prognosis, although the process is not understood. In this study, we explored the relationship between HER2 and inflammation, comparing the effects of overexpressing wild-type or mutated inactive forms of HER2 in primary human breast cells. Wild-type HER2 elicited a profound transcriptional inflammatory profile, including marked elevation of interleukin-6 (IL-6) expression, which we established to be a critical determinant of HER2 oncogenesis. Mechanistic investigations revealed that IL-6 secretion induced by HER2 overexpression activated Stat3 and altered gene expression, enforcing an autocrine loop of IL-6/Stat3 expression. Both mouse and human in vivo models of HER2-amplified breast carcinoma relied critically on this HER2-IL-6-Stat3 signaling pathway. Our studies offer the first direct evidence linking HER2 to a systemic inflammatory mechanism that orchestrates HER2-mediated tumor growth. We suggest that the HER2-IL-6-STAT3 signaling axis we have defined in breast cancer could prompt new therapeutic or prevention strategies for treatment of HER2-amplified cancers.

An unusual cause of carpal tunnel syndrome.

Most cases of carpal tunnel syndrome are idiopathic. One condition associated with carpal tunnel syndrome is a lipofibromatous hamartoma. We describe a case of a lipofibromatous hamartoma presenting as a soft tissue wrist swelling with associated symptoms and signs of carpal tunnel syndrome. We advocate that all soft tissue swellings of the wrist with associated neurological signs be investigated appropriately, avoiding unnecessary additional surgery.

X-linked inhibitor of apoptosis protein inhibits apoptosis in inflammatory breast cancer cells with acquired resistance to an ErbB1/2 tyrosine kinase inhibitor.

Inflammatory breast cancer (IBC) is a highly aggressive subtype of breast cancer that is often characterized by ErbB2 overexpression. ErbB2 targeting is clinically relevant using trastuzumab (anti-ErbB2 antibody) and lapatinib (small-molecule ErbB1/2 inhibitor). However, acquired resistance is a common outcome even in IBC patients who show an initial clinical response, which limits the efficacy of these agents. In the present study, using a clonal population of GW583340 (lapatinib analogue, ErbB1/2 inhibitor)-resistant IBC cells, we identified the overexpression of an antiapoptotic protein, X-linked inhibitor of apoptosis protein (XIAP), in acquired resistance to GW583340 in both ErbB2-overexpressing SUM190 and ErbB1-activated SUM149 cell lines derived from primary IBC tumors. A marked decrease in p-ErbB2, p-ErbB1, and downstream signaling was evident in the GW583340-resistant cells (rSUM190 and rSUM149) similar to parental counterparts treated with the drug, suggesting that the primary mechanism of action of GW583340 was not compromised in resistant cells. However, rSUM190 and rSUM149 cells growing in GW583340 had significant XIAP overexpression and resistance to GW583340-mediated apoptosis. Additionally, stable XIAP overexpression using a lentiviral system reversed sensitivity to GW583340 in parental cells. The observed overexpression was identified to be caused by IRES-mediated XIAP translation. XIAP downregulation in rSUM190 and rSUM149 cells using a small-molecule inhibitor (embelin), which abrogates the XIAP/procaspase-9 interaction, resulted in decreased viability, showing that XIAP is required for survival of cells with acquired resistance to GW583340. These studies establish the feasibility of development of an XIAP inhibitor that potentiates apoptosis for use in IBC patients with resistance to ErbB2-targeting agents.