Cyclooxygenase-2 Expression In Breast Cancer Research Articles

P149: Role of Cyclooxygenase 2 (COX-2) in prognosis of breast cancer

Introduction: COX-2 is a well-known component of inflammatory cascade. It also regulates tumour growth, invasion and metastasis in breast cancer. This study investigated the association between COX-2 expression in breast cancer as well as its association with other established prognostic indicators like tumour size, lymph nodal status, stage, grade, NPI and histological subtype, and aims to validate the role of overexpression of COX-2 as a prognostic marker in breast cancer.

COX-2 Expression in Breast Cancer and Impact on Survival Outcomes

Purpose: The inducible inflammatory enzyme cyclooxygenase-2 (COX-2) favors carcinogenesis, but its expression in breast tumors presents great variability, with controversial prognostic impact. Here, we characterize COX-2 protein levels in breast tumors by immunohistochemistry according to gene polymorphisms, and evaluate if tumor COX-2 protein levels or mRNA are associated with survival outcomes.

The prognostic impact of COX-2 expression in breast cancer depends on oral contraceptive history, preoperative NSAID use, and tumor size.

The association between tumor cyclooxygenase 2 (COX-2) expression and breast cancer prognosis has been inconsistent. The purpose of this study was to evaluate the prognostic significance of COX-2 tumor expression according to adjuvant treatment, and potential effect modifications of non-steroid anti-inflammatory drug (NSAID) use, and other tumor and lifestyle factors. A prospective cohort of 1,116 patients with primary breast cancer in Lund, Sweden, included 2002-2012 was followed until June 2014 (median 5 years). Tumor-specific COX-2 expression was evaluated on tissue microarrays using immunohistochemistry. Associations between COX-2 intensity (negative, weak-moderate, high) and patient and tumor characteristics as well as prognosis were analyzed. Tumor-specific COX-2 expression was available for 911 patients and was significantly associated with higher age at diagnosis and less aggressive tumor characteristics. Higher COX-2 expression was associated with lower risk for breast cancer events during the first five years of follow-up, adj HR 0.60 (95%CI: 0.37-0.97), per category. The association between COX-2 expression and prognosis was significantly modified by oral contraceptive (OC) use (Pinteraction = 0.048), preoperative NSAID use (Pinteraction = 0.009), and tumor size (Pinteraction = 0.039). COX-2 negativity was associated with increased risk for events during the first five years in ever OC users, adj HR 1.94 (1.01-3.72) and during the 11-year follow-up in preoperative NSAID users, adj HR 4.51 (1.18-11.44) as well as in patients with large tumors, adj HR 2.57 (1.28-5.15). In conclusion, this study, one of the largest evaluating COX-2 expression in breast cancer, indicates that the prognostic impact of COX-2 expression depends on host factors and tumor characteristics.

Abstract 3931: Tumor COX-2 expression is associated with less aggressive tumors and better five-year prognosis in breast cancer patients

Abstract Introduction: Cyclooxygenase-2 (COX-2) is a mediator of inflammation and regulates aromatase expression, suggesting a potentially important role in breast cancer. The prognostic role of COX-2 expression in breast cancer is still debated. The aim of this study was to analyze tumor COX-2 expression in relation to age and tumor characteristics, and to elucidate whether COX-2 expression was associated with breast cancer prognosis. Materials and methods: COX-2 expression was evaluated in invasive tumors from 984 primary breast cancer patients from a population-based prospective cohort from Lund, Sweden. The patients were included as of 2002 and were followed for up to 11 years. The median follow-up time for patients still at risk was five years. Disease-free survival was assessed by Kaplan-Meier and LogRank test. Adjusted Hazard Ratios (HR) were obtained by Cox regression and adjusted for invasive tumor size, axillary lymph node involvement, histological grade, estrogen receptor (ER) status, and age at inclusion. Results: Immunohistochemical COX-2 expression was available for 911 patients and the intensity was classified as negative (n = 82; 9.0%) /weak or moderate (n = 723; 79.4%) /strong (n = 106; 11.6%). Patients 50 years or older at inclusion had higher COX-2 expression compared to younger patients (Ptrend = 0.05). Overall, higher COX-2 tumor expression was also observed among patients with ER+ tumors (Ptrend<0.0001) and among patients with tumors of lower histological grade (Ptrend<0.0001) compared to patients with ER- tumors or higher histological grade. COX-2 tumor expression was not associated with tumor size or axillary lymph node status. Higher COX-2 expression was associated with lower risk for any breast cancer event in the univariable (LogRank Ptrend = 0.02), but not in the multivariable model, adjusted HR 0.73 (95% CI: 0.49-1.09) per category. However, higher COX-2 expression was associated with lower risk for events during the first five years of follow-up (LogRank Ptrend = 0.0003), adjusted HR 0.60 (95% CI: 0.37-0.97) per category. Conclusion: Higher COX-2 expression was associated with less aggressive tumor characteristics and lower risk for any breast cancer event during the first five years of follow-up but not thereafter, in this population-based cohort of breast cancer patients. This study indicates that COX-2 expression in breast cancer may carry short-term prognostic information independently of established clinical and tumor characteristics. Citation Format: Maria Simonsson, Sofie Björner, Andrea Markkula, Björn Nodin, Karin Jirström, Carsten Rose, Signe Borgquist, Christian Ingvar, Helena Jernström. Tumor COX-2 expression is associated with less aggressive tumors and better five-year prognosis in breast cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3931.

Stromal, rather than epithelial cyclooxygenase-2 (COX-2) expression is associated with overall survival of breast cancer patients

BackgroundPrognostic value of enhanced COX-2 expression in breast cancer has been controversial for a long time. The opinions vary widely between studies. Moreover, significant majority of studies considered only COX-2 expression in cancer epithelial cells.MethodsWe examined the prognostic value of COX-2 expression in both epithelial and stromal cells using three different antibodies and three algorithms of immunohistochemical scoring and categorizing the tumours into COX-2 overexpressing groups.ResultsOur results demonstrate that COX-2 expression in stromal cells is independent prognostic factor indicating worse overall survival of patients. Such a result was obtained using each of the three antibodies and two of the algorithms used for evaluations of COX-2 expression levels. We also show that immunohistochemical assessment of the prognostic value of COX-2 expression in cancer epithelial cells depends to a large extent on a combination of primary antibodies and algorithms used for determination of the COX-2 over-expressing tumours.ConclusionsOur results indicate that stromal expression of COX-2 is independent prognostic parameter relatively insensitive to variations in sensitivity of antibodies used for its determination. Wide scatter of the published results concerning prognostic value of COX-2 expression in breast cancer tissues seems to be due to a large extent to multitude of antibodies and scoring algorithms used by different groups.

Physiological COX-2 Expression in Breast Epithelium Associates with COX-2 Levels in Ductal Carcinoma in Situ and Invasive Breast Cancer in Young Women

Cyclooxygenase-2 (COX-2) overexpression is implicated in increased risk and poorer outcomes in breast cancer in young women. We investigated COX-2 regulation in normal premenopausal breast tissue and its relationship to malignancy in young women. Quantitative COX-2 immunohistochemistry was performed on adjacent normal and breast cancer tissues from 96 premenopausal women with known clinical reproductive histories, and on rat mammary glands with distinct ovarian hormone exposures. COX-2 expression in the normal breast epithelium varied more than 40-fold between women and was associated with COX-2 expression levels in ductal carcinoma in situ and invasive cancer. Normal breast COX-2 expression was independent of known breast cancer prognostic indicators, including tumor stage and clinical subtype, indicating that factors regulating physiological COX-2 expression may be the primary drivers of COX-2 expression in breast cancer. Ovarian hormones, particularly at pregnancy levels, were identified as modulators of COX-2 in normal mammary epithelium. However, serial breast biopsy analysis in nonpregnant premenopausal women suggested relatively stable baseline levels of COX-2 expression, which persisted independent of menstrual cycling. These data provide impetus to investigate how baseline COX-2 expression is regulated in premenopausal breast tissue because COX-2 levels in normal breast epithelium may prove to be an indicator of breast cancer risk in young women, and predict the chemopreventive and therapeutic efficacy of COX-2 inhibitors in this population.

Abstract P4-08-11: Surface Plasmon Resonance (SPR) Analysis of COX-2 Expression for Early Detection and Progression of Breast Cancer and Evaluation of a Novel Class of Peptides as Its Inhibitor

Abstract Background: Cyclooxygenase-2 (COX-2) over expression has been observed in different cancers. Till date, COX-2 expression in breast cancer has been studied using RT-PCR and immunohistochemistry. The aim of this study was to use surface plasmon resonance (SPR) technology for determining the expression levels of COX-2 in breast cancer and design peptide inhibitors to evaluate their enzyme inhibition in vitro. Patients and methods: This case-controlled study was performed on 84 biopsy proven breast cancer patients having invasive ductal carcinoma and 40 age, sex and ethnicity matched healthy subjects. Blood and tissue samples were collected and serum and tissue lysate was prepared. Serum and tissue levels of COX-2 were evaluated using SPR where samples were allowed to flow over anti-COX-2 antibody immobilized sensor chip to obtain the respective RUs. Similarly, standard curve of COX-2 was prepared from cloned, expressed and purified protein to deduce the concentrations in different samples. To evaluate enzyme inhibition, fifteen peptides were synthesized using the solid and solution-phase peptide synthesis based on the active site structure of COX-2 and enzyme activity was evaluated spectrophotometrically. Results: A significant increase in COX-2 levels in breast cancer patients 11.23-30.77μg/ml (Mean±SD=14.55±5.74) as compared to normal controls 2.13-5.16µg/ml (Mean±SD=3.71±0.86) (P>0.0001) was observed. Serum COX-2 levels were significantly higher (P<0.0061) in patients with lymph node involvement. More than 65% patients showed significantly (P<0.0025) reduced COX-2 levels after chemotherapy. This was confirmed by western blot to check tissue level expression and spectrophotometrically to determine the activity of COX-2 at different stages. In addition, the peptides showed significant in vitro enzyme inhibition, and had a KD ranging from 1 X 10-8 to 1X10-10. Conclusion: SPR is a useful proteomic technique for early detection and monitoring progession of breast cancer and peptides are a novel class of COX-2 inhibitors that can be further developed for anti-tumor therapy. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-08-11.

COX-2 Expression in Invasive Breast Cancer

Lipoxygenases (LOX) and cyclooxygenases (COX) are key mediators of arachidonic acid metabolism. Recently, studies have reported that human breast carcinomas aberrantly express LOX and cyclooxygenase-2 (COX-2), and that decreased levels of 15-lipoxygenase (15-LOX) and raised levels of COX-2 and 12-LOX have prognostic value in patients with breast cancer. 15-LOX was significantly reduced with increasing stage, and in patients who developed metastatic disease, local recurrence, and/or died. With high COX-2, patients developed local recurrence, died from breast cancer and had reduced disease-free and disease-related overall survival in estrogen receptor (ER)-negative but not ER-positive disease. COX-2 expression is also associated with increased angiogenesis, lymph node metastasis, and Her2-neu overexpression. The purpose of this study is to evaluate COX-2 expression in breast cancer and to determine its correlation with prognostic parameters and outcome. Five tissue microarrays were constructed from 43 breast carcinomas and 5 normal breast tissues, represented by 1 mm cores in triplicate from each of 3 foci. Tissue microarray cores were immunostained with monoclonal COX-2. Expression was assessed as intensity and scored as percentage of cells positive. Prognostic parameters and follow-up information were obtained from the hospital records of Mexican Oncology Hospital, Mexico, where the carcinomas were diagnosed. Ninety-five percent (41/43) of the breast carcinomas showed cytoplasmic COX-2 expression. COX-2 intensity and percentage of cells positive correlated significantly with size of carcinoma (P=0.0271; P=0.0539, respectively). COX-2 intensity correlated significantly with histologic grade (P=0.0182). COX-2 did not correlate with outcome (disease-free and overall survival). There was no significant correlation between COX-2 and ER. In conclusion, COX-2 correlates with poor prognostic markers in breast cancer (large tumor size and high tumor grade), but not with outcome. The therapeutic value of COX-2 inhibitors in COX-2 positive breast cancer patients requires further investigation.