COX-1 and COX-2 expression in stage I and II invasive cervical carcinoma: relationship to disease relapse and long-term survival

Cyclooxygenase-1 (COX-1) and COX-1 Inhibitors in Cancer: A Review of Oncology and Medicinal Chemistry Literature

Prostaglandins and thromboxane are lipid signaling molecules deriving from arachidonic acid by the action of the cyclooxygenase isoenzymes COX-1 and COX-2. The role of cyclooxygenases (particularly COX-2) and prostaglandins (particularly PGE₂) in cancer-related inflammation has been extensively investigated. In contrast, COX-1 has received less attention, although its expression increases in several human cancers and a pathogenetic role emerges from experimental models. COX-1 and COX-2 isoforms seem to operate in a coordinate manner in cancer pathophysiology, especially in the tumorigenesis process. However, in some cases, exemplified by the serous ovarian carcinoma, COX-1 plays a pivotal role, suggesting that other histopathological and molecular subtypes of cancer disease could share this feature. Importantly, the analysis of functional implications of COX-1-signaling, as well as of pharmacological action of COX-1-selective inhibitors, should not be restricted to the COX pathway and to the effects of prostaglandins already known for their ability of affecting the tumor phenotype. A knowledge-based choice of the most appropriate tumor cell models, and a major effort in investigating the COX-1 issue in the more general context of arachidonic acid metabolic network by using the systems biology approaches, should be strongly encouraged.

Prognostic significance of cyclooxygenase-2 in cervical cancer: a meta-analysis

Published data on the prognostic value of cyclooxygenase-2 (COX-2) overexpression in cervical cancer are conflicting and heterogeneous. We performed a meta-analysis to more precisely estimate its prognostic significance. The pooled hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the effects. Twenty-three studies with 1,477 cervical cancer patients were selected to evaluate the association between COX-2 and overall survival (OS), disease-free survival (DFS), response to chemoradiation (RC) and clinicopathological parameters. High COX-2 expression predicted poor OS (HR: 2.53, 95% CI: 1.54-4.18), DFS (HR: 2.41, 95% CI: 1.58-3.69) and RC (OR: 3.03, 95% CI: 1.97-4.64). Subgroup analyses showed that COX-2 overexpression was related significantly with poor OS in patients treated by chemoradiation or surgery, and in patients with squamous cell carcinoma, respectively. Besides, COX-2 overexpression was related significantly with poor DFS in chemoradiation subgroup. Furthermore, COX-2 overexpression was associated with poor RC in patients who received "FP" regimen or "P" regimen. Additionally, there were significant associations between COX-2 expression and all clinicopathological parameters except tumor grade. The pooled ORs (95% CI) were as follows: 1.49 (1.09-2.04) for age, 1.77 (1.22-2.56) for lymph node metastasis, 1.04 (0.74-1.47) for tumor grade, 1.71 (1.12-2.64) for tumor size, 2.38 (1.28-4.45) for FIGO stage, 3.96 (2.32-6.77) for histological type, 2.45(1.10-5.42) for parametrical involvement. This meta-analysis indicated that COX-2 overexpression might be an unfavorable prognostic and a chemoradiation resistance predictive factor for cervical cancer; it could potentially help to stratify patients further in clinical treatment.

Cyclooxygenase isozymes in oral squamous cell carcinoma:a real-time RT-PCR study with clinic pathological correlations

COX-2 expression in tumour cells has been associated with carcinogenesis in many human neoplasms, including head and neck cancer, while the COX-1 isoform of the cyclooxygenase enzyme is constitutively expressed in normal tissues. We measured COX-1 and COX-2 m-RNA expression in samples of both oral cancer and matched oral mucosa from 22 patients by RealTime RT-PCR; clinic pathological data (grading, TNM staging, inflammation, follow-up) of all patients were available for statistical evaluation. Most of the tumor samples in our study expressed at least one cyclooxygenase enzyme (COX-1 or COX-2 mRNA) more than their matched normal oral mucosa (p<0.05), with no correlation with the entity of inflammation, and a significant inverse relationship was found between COX-1 and COX-2 in each sample. Higher levels of COX-2 expression were associated with poor disease-free survival (p<0.05), but not with overall survival and higher tumor stage and grade. Our results suggest that COX-1 may play a role in oral carcinogenesis, and could be regarded as a potential therapeutic target by chemo preventive drugs; moreover, COX-2 expression might be addressed as a new prognostic tool in the clinical management of OSCC.