Immunohistochemical Expression of Cytosolic Phospholipase A2α in Non-small Cell Lung Carcinoma

Purpose: Cytosolic phospholipase A2α is the main target enzyme for the non steroidal anti-inflammatorydrugs that have been shown to suppress carcinogenesis in both experimental model and epidemiologic studies.
Methods: We examined cPLA2α expression in normal, premalignant bronchial epithelial cells and nonsmall celllung carcinoma (NSCLC) samples using an immunohistochemical staining technique. Included in the currentstudy were 76 NSCLC samples and 52 bronchial biopsy samples obtained.
Results: In the normal bronchialepithelium, cPLA2α expression was found to be completely negative whereas positive cPLA2α expression waslimited to a few macrophages, inflammatory cells. There were relatively more cPLA2α positive tumors, as definedby positive staining in >10% of tumor cells 24 of 76 tumors (32%). When tumor types were considered, there weremore cPLA2α positive adenocarcinomas compared with squamous cell carcinomas (17 of 36 adenocarcinomas(47%) vs. 6 of 34 squamous cell carcinomas (18%); P=0.02). Although smokers tended to have more cPLA2αpositive tumors than nonsmokers (23 of 64 tumors in the smokers (36%) vs. 1 of 12 tumors in the nonsmokers(8%); P=0.06).
Conclusion: The results of the current study suggest that cPLA2α expression may not be a usefulintermediate biomarker in bronchial chemoprevention trials. Nevertheless, considering the patterns of cPLA2αexpression in tumor cells, cPLA2α expression status may be a useful parameter when designing treatmentstrategies for a subset of NSCLC patients.