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Cyclooxygenase-2 expression in pediatric sarcomas
David S Dickens1, Rafal Kozielski, Javed Khan
1Department of Pediatrics, Division of Hematology/Oncology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA. dicq3z@chmc.org
Abstract:
Therapies for metastatic pediatric sarcomas have reached maximum tolerated doses, but continue to provide suboptimal cure rates. Additionally, these treatments are associated with numerous short- and long-term side effects. Therefore, the search for newer, less toxic therapeutic agents is warranted. Overexpression of the inducible enzyme, cyclooxygenase-2 (COX-2), has been discovered in a variety of adult solid tumors and numerous studies have shown COX-2 inhibitors to have significant antiproliferative effects. Therefore, we sought to determine the expression of COX-2 in pediatric sarcomas. We evaluated rhabdomyosarcoma (RMS), osteosarcoma (OS), and Ewing sarcoma (EWS) samples for COX-2 expression by immunohistochemical analysis as well as by cDNA microarray analysis. COX-2 expression was detected in 48/58 (82.8%) tumors by immunohistochemistry and in an additional 52/59 (88.1%) tumors tested by microarray gene analysis. There was a trend toward increased COX-2 expression in metastatic rhabdomyosarcoma and osteosarcoma, though it did not reach clinical significance. The degree of COX-2 immunoreactivity did not vary significantly with other clinicopathologic features such as age, gender, or histologic classification. We conclude that the majority of these pediatric sarcoma samples express COX-2 to varying degrees. Therefore, studies testing the efficacy of COX-2 inhibitors in the treatment of pediatric sarcomas are warranted.
Insights
Pediatric sarcomas like rhabdomyosarcoma, osteosarcoma, and Ewing sarcoma frequently overexpress cyclooxygenase-2 (COX-2). This suggests that targeting COX-2 with inhibitors may offer a less toxic therapeutic approach for these challenging childhood cancers.
Area of Science:
- Oncology
- Molecular Biology
- Pediatric Cancer Research
Background:
- Current therapies for metastatic pediatric sarcomas have limited efficacy and significant side effects.
- Cyclooxygenase-2 (COX-2) is overexpressed in various adult solid tumors, with COX-2 inhibitors demonstrating antiproliferative effects.
Purpose of the Study:
- To investigate the expression of cyclooxygenase-2 (COX-2) in pediatric sarcoma samples.
- To assess the potential of COX-2 as a therapeutic target in pediatric sarcomas.
Main Methods:
- Immunohistochemical analysis of COX-2 expression in pediatric sarcoma tissues.
- cDNA microarray analysis to evaluate COX-2 gene expression in rhabdomyosarcoma (RMS), osteosarcoma (OS), and Ewing sarcoma (EWS).
Main Results:
- COX-2 expression was detected in a high percentage of pediatric sarcoma samples (82.8% by immunohistochemistry, 88.1% by microarray).
- A trend towards increased COX-2 expression was observed in metastatic RMS and OS, but did not reach statistical significance.
- No significant correlation was found between COX-2 immunoreactivity and clinicopathologic features like age, gender, or histology.
Conclusions:
- The majority of pediatric sarcomas (RMS, OS, EWS) express cyclooxygenase-2 (COX-2).
- These findings support further investigation into the efficacy of COX-2 inhibitors as a novel therapeutic strategy for pediatric sarcomas.