Donal J. Brennan

Leukocyte Complexity Predicts Breast Cancer Survival and Functionally Regulates Response to Chemotherapy

UNLABELLED Immune-regulated pathways influence multiple aspects of cancer development. In this article we demonstrate that both macrophage abundance and T-cell abundance in breast cancer represent prognostic indicators for recurrence-free and overall survival. We provide evidence that response to chemotherapy is in part regulated by these leukocytes; cytotoxic therapies induce mammary epithelial cells to produce monocyte/macrophage recruitment factors, including colony stimulating factor 1 (CSF1) and interleukin-34, which together enhance CSF1 receptor (CSF1R)-dependent macrophage infiltration. Blockade of macrophage recruitment with CSF1R-signaling antagonists, in combination with paclitaxel, improved survival of mammary tumor-bearing mice by slowing primary tumor development and reducing pulmonary metastasis. These improved aspects of mammary carcinogenesis were accompanied by decreased vessel density and appearance of antitumor immune programs fostering tumor suppression in a CD8+ T-cell-dependent manner. These data provide a rationale for targeting macrophage recruitment/response pathways, notably CSF1R, in combination with cytotoxic therapy, and identification of a breast cancer population likely to benefit from this novel therapeutic approach. SIGNIFICANCE These findings reveal that response to chemotherapy is in part regulated by the tumor immune microenvironment and that common cytotoxic drugs induce neoplastic cells to produce monocyte/macrophage recruitment factors, which in turn enhance macrophage infiltration into mammary adenocarcinomas. Blockade of pathways mediating macrophage recruitment, in combination with chemotherapy, significantly decreases primary tumor progression, reduces metastasis, and improves survival by CD8+ T-cell-dependent mechanisms, thus indicating that the immune microenvironment of tumors can be reprogrammed to instead foster antitumor immunity and improve response to cytotoxic therapy.

Targeting Tumor-Infiltrating Macrophages Decreases Tumor-Initiating Cells, Relieves Immunosuppression, and Improves Chemotherapeutic Responses

Tumor-infiltrating immune cells can promote chemoresistance and metastatic spread in aggressive tumors. Consequently, the type and quality of immune responses present in the neoplastic stroma are highly predictive of patient outcome in several cancer types. In addition to host immune responses, intrinsic tumor cell activities that mimic stem cell properties have been linked to chemoresistance, metastatic dissemination, and the induction of immune suppression. Cancer stem cells are far from a static cell population; rather, their presence seems to be controlled by highly dynamic processes that are dependent on cues from the tumor stroma. However, the impact immune responses have on tumor stem cell differentiation or expansion is not well understood. In this study, we show that targeting tumor-infiltrating macrophages (TAM) and inflammatory monocytes by inhibiting either the myeloid cell receptors colony-stimulating factor-1 receptor (CSF1R) or chemokine (C-C motif) receptor 2 (CCR2) decreases the number of tumor-initiating cells (TIC) in pancreatic tumors. Targeting CCR2 or CSF1R improves chemotherapeutic efficacy, inhibits metastasis, and increases antitumor T-cell responses. Tumor-educated macrophages also directly enhanced the tumor-initiating capacity of pancreatic tumor cells by activating the transcription factor STAT3, thereby facilitating macrophage-mediated suppression of CD8(+) T lymphocytes. Together, our findings show how targeting TAMs can effectively overcome therapeutic resistance mediated by TICs.

Interleukin-6 as a Therapeutic Target in Human Ovarian Cancer

Purpose: We investigated whether inhibition of interleukin 6 (IL-6) has therapeutic activity in ovarian cancer via abrogation of a tumor-promoting cytokine network. Experimental Design: We combined preclinical and in silico experiments with a phase 2 clinical trial of the anti-IL-6 antibody siltuximab in patients with platinum-resistant ovarian cancer. Results: Automated immunohistochemistry on tissue microarrays from 221 ovarian cancer cases showed that intensity of IL-6 staining in malignant cells significantly associated with poor prognosis. Treatment of ovarian cancer cells with siltuximab reduced constitutive cytokine and chemokine production and also inhibited IL-6 signaling, tumor growth, the tumor-associated macrophage infiltrate and angiogenesis in IL-6–producing intraperitoneal ovarian cancer xenografts. In the clinical trial, the primary endpoint was response rate as assessed by combined RECIST and CA125 criteria. One patient of eighteen evaluable had a partial response, while seven others had periods of disease stabilization. In patients treated for 6 months, there was a significant decline in plasma levels of IL-6–regulated CCL2, CXCL12, and VEGF. Gene expression levels of factors that were reduced by siltuximab treatment in the patients significantly correlated with high IL-6 pathway gene expression and macrophage markers in microarray analyses of ovarian cancer biopsies. Conclusion: IL-6 stimulates inflammatory cytokine production, tumor angiogenesis, and the tumor macrophage infiltrate in ovarian cancer and these actions can be inhibited by a neutralizing anti-IL-6 antibody in preclinical and clinical studies. Clin Cancer Res; 17(18); 6083–96. ©2011 AACR.

Prognostic Significance of Stromal Platelet-Derived Growth Factor beta-Receptor Expression in Human Breast Cancer

This study systematically analyzes platelet-derived growth factor (PDGF) receptor expression in six types of common tumors as well as examines associations between PDGF beta-receptor status and clinicopathological characteristics in breast cancer. PDGF receptor expression was determined by immunohistochemistry on tumor tissue microarrays. Breast tumor data were combined with prognostic factors and related to outcome endpoints. PDGF alpha- and beta-receptors were independently expressed, at variable frequencies, in the tumor stroma of all tested tumor types. There was a significant association between PDGF beta-receptor expression on fibroblasts and perivascular cells in individual colon and prostate tumors. In breast cancer, high stromal PDGF beta-receptor expression was significantly associated with high histopathological grade, estrogen receptor negativity, and high HER2 expression. High stromal PDGF beta-receptor expression was correlated with significantly shorter recurrence-free and breast cancer-specific survival. The prognostic significance of stromal PDGF beta-receptor expression was particularly prominent in tumors from premenopausal women. Stromal PDGF alpha- and beta-receptor expression is a common, but variable and independent, property of solid tumors. In breast cancer, stromal PDGF beta-receptor expression significantly correlates with less favorable clinicopathological parameters and shorter survival. These findings highlight the prognostic significance of stromal markers and should be considered in ongoing clinical development of PDGF receptor inhibitors.

Antibody-based proteomics: fast-tracking molecular diagnostics in oncology

The effective implementation of personalized cancer therapeutic regimens depends on the successful identification and translation of informative biomarkers to aid clinical decision making. Antibody-based proteomics occupies a pivotal space in the cancer biomarker discovery and validation pipeline, facilitating the high-throughput evaluation of candidate markers. Although the clinical utility of these emerging technologies remains to be established, the traditional use of antibodies as affinity reagents in clinical diagnostic and predictive assays suggests that the rapid translation of such approaches is an achievable goal. Furthermore, in combination with, or as alternatives to, genomic and transcriptomic methods for patient stratification, antibody-based proteomics approaches offer the promise of additional insight into cancer disease states. In this Review, we discuss the current status of antibody-based proteomics and its contribution to the development of new assays that are crucial for the realization of individualized cancer therapy.

Comparative analysis of international cesarean delivery rates using 10-group classification identifies significant variation in spontaneous labor.

OBJECTIVE Cesarean section (CS) rates continue to rise throughout the developed world. The aim of this study was to highlight variations in obstetric populations and practices and to identify variations in CS rates in different institutions. STUDY DESIGN Data from 9 institutional cohorts (total, 47,402; range, 1962-7985) from 9 different countries were examined using a 10-group classification system based on 4 characteristics of every pregnancy, namely single/multiple, nulliparity/multiparity, multiparity with CS scar, spontaneous/induced labor onset and term (>or=37 weeks) gestation. RESULTS Overall CS rates correlated with CS rates in singleton cephalic nullipara (r = 0.992; P < .001). Whereas CS rates in induced labor were similar, greatest institutional variation were seen in spontaneously laboring multiparas (6.7-fold difference) and nulliparas (3.7-fold difference). CONCLUSION Ten-group analysis of international obstetric cesarean practice identifies wide variations in women in spontaneous cephalic term labor, a low-risk cohort amenable to effective intrapartum corrective intervention.

CA IX is an Independent Prognostic Marker in Premenopausal Breast Cancer Patients with One to Three Positive Lymph Nodes and a Putative Marker of Radiation Resistance

Purpose: Hypoxia in breast cancer is associated with poor prognosis and down-regulation of the estrogen receptor. Carbonic anhydrase IX (CA IX) is a hypoxia-inducible gene that has been associated with poor outcome in many epithelial cancers. Previous studies of CA IX in breast cancer have been carried out on mixed cohorts of premenopausal and postmenopausal patients with locally advanced disease and varying treatment regimens. We examined the potential prognostic and predictive role of CA IX in premenopausal breast cancer patients. Experimental Design: Using tissue microarrays, we analyzed CA IX expression in 400 stage II breast cancers from premenopausal women. The patients had previously participated in a randomized control trial comparing 2 years of tamoxifen to no systemic adjuvant treatment. Median follow-up was 13.9 years. Results: CA IX expression correlated positively with tumor size, grade, hypoxia-inducible factor 1α, Ki-67, cyclin E, and cyclin A2 expression. CA IX expression correlated negatively with cyclin D1, estrogen receptor, and progesterone receptor. CA IX expression was associated with a reduced relapse-free survival (P = 0.032), overall survival (P = 0.022), and breast cancer–specific survival (P = 0.005). Multivariate analysis revealed that CA IX was an independent prognostic marker in untreated patients with one to three positive lymph nodes (hazard ratio, 3.2; 95% confidence interval, 1.15-9.13; P = 0.027). Conclusion: CA IX is marker of poor prognosis in premenopausal breast cancer patients and it is an independent predictor of survival in patients with one to three positive lymph nodes. As all these patients received locoregional radiation therapy, CA IX may be associated with resistance to radiotherapy.

Increased claudin-4 expression is associated with poor prognosis and high tumour grade in breast cancer

The role of intercellular tight junctions in breast epithelial cells is traditionally thought to be in maintaining polarity and barrier function. However, claudin‐4, a tight junction protein, is overexpressed in breast tumour cells compared to normal epithelial cells, which generally corresponds to a loss in polarity. The aim of this study was to investigate the distribution and potential clinical value of claudin‐4 in breast cancer, and to evaluate its usefulness as a prognostic and predictive biomarker. Expression of claudin‐4 was initially examined by Western blot analysis in a cohort of 88 breast tumours, and was found to correlate positively with tumour grade and negatively with ER. Claudin‐4 expression was then evaluated by immunohistochemistry in a larger cohort of 299 tumours represented on a tissue microarray. Claudin‐4 expression correlated positively with tumour grade and Her2, and negatively with ER. High claudin‐4 expression was also associated with worse breast cancer‐specific survival (p = 0.003), recurrence‐free survival (p = 0.025) and overall survival (p = 0.034). Multivariate analysis revealed that claudin‐4 independently predicted survival in the entire cohort (HR 1.95; 95%CI 1.01–3.79; p = 0.047) and in the ER positive subgroup treated with adjuvant tamoxifen (HR 4.34; 95%CI 1.14–16.53; p = 0.032). This relationship between increased claudin‐4 expression and adverse outcome was validated at the mRNA level in a DNA microarray dataset of 295 breast tumours. We conclude that high levels of claudin‐4 protein are associated with adverse outcome in breast cancer patients, including the subgroup of patients treated with adjuvant tamoxifen.

Novel image analysis approach for quantifying expression of nuclear proteins assessed by immunohistochemistry: application to measurement of oestrogen and progesterone receptor levels in breast cancer

IntroductionManual interpretation of immunohistochemistry (IHC) is a subjective, time-consuming and variable process, with an inherent intra-observer and inter-observer variability. Automated image analysis approaches offer the possibility of developing rapid, uniform indicators of IHC staining. In the present article we describe the development of a novel approach for automatically quantifying oestrogen receptor (ER) and progesterone receptor (PR) protein expression assessed by IHC in primary breast cancer.MethodsTwo cohorts of breast cancer patients (n = 743) were used in the study. Digital images of breast cancer tissue microarrays were captured using the Aperio ScanScope XT slide scanner (Aperio Technologies, Vista, CA, USA). Image analysis algorithms were developed using MatLab 7 (MathWorks, Apple Hill Drive, MA, USA). A fully automated nuclear algorithm was developed to discriminate tumour from normal tissue and to quantify ER and PR expression in both cohorts. Random forest clustering was employed to identify optimum thresholds for survival analysis.ResultsThe accuracy of the nuclear algorithm was initially confirmed by a histopathologist, who validated the output in 18 representative images. In these 18 samples, an excellent correlation was evident between the results obtained by manual and automated analysis (Spearmans ρ = 0.9, P < 0.001). Optimum thresholds for survival analysis were identified using random forest clustering. This revealed 7% positive tumour cells as the optimum threshold for the ER and 5% positive tumour cells for the PR. Moreover, a 7% cutoff level for the ER predicted a better response to tamoxifen than the currently used 10% threshold. Finally, linear regression was employed to demonstrate a more homogeneous pattern of expression for the ER (R = 0.860) than for the PR (R = 0.681).ConclusionsIn summary, we present data on the automated quantification of the ER and the PR in 743 primary breast tumours using a novel unsupervised image analysis algorithm. This novel approach provides a useful tool for the quantification of biomarkers on tissue specimens, as well as for objective identification of appropriate cutoff thresholds for biomarker positivity. It also offers the potential to identify proteins with a homogeneous pattern of expression.

Pulmonary Embolism in Pregnancy: Comparison of Pulmonary CT Angiography and Lung Scintigraphy

OBJECTIVE The purpose of this study was to retrospectively compare the diagnostic adequacy of lung scintigraphy with that of pulmonary CT angiography (CTA) in the care of pregnant patients with suspected pulmonary embolism. MATERIALS AND METHODS Patient characteristics, radiology report content, additional imaging performed, final diagnosis, and diagnostic adequacy were recorded for pregnant patients consecutively referred for lung scintigraphy or pulmonary CTA according to physician preference. Measurements of pulmonary arterial enhancement were performed on all pulmonary CTA images of pregnant patients. Lung scintigraphy and pulmonary CTA studies deemed inadequate for diagnosis at the time of image acquisition were further assessed, and the cause of diagnostic inadequacy was determined. The relative contribution of the inferior vena cava to the right side of the heart was measured on nondiagnostic CTA images and compared with that on CTA images of age-matched nonpregnant women, who were the controls. RESULTS Twenty-eight pulmonary CTA examinations were performed on 25 pregnant patients, and 25 lung scintigraphic studies were performed on 25 pregnant patients. Lung scintigraphy was more frequently adequate for diagnosis than was pulmonary CTA (4% vs 35.7%) (p = 0.0058). Pulmonary CTA had a higher diagnostic inadequacy rate among pregnant than nonpregnant women (35.7% vs 2.1%) (p < 0.001). Transient interruption of contrast material by unopacified blood from the inferior vena cava was identified in eight of 10 nondiagnostic pulmonary CTA studies. CONCLUSION We found that lung scintigraphy was more reliable than pulmonary CTA in pregnant patients. Transient interruption of contrast material by unopacified blood from the inferior vena cava is a common finding at pulmonary CTA of pregnant patients.