Immunohistochemical expression of cytosolic phospholipase A2α in non-small cell lung carcinoma

Cytosolic phospholipase A2α is the main target enzyme for the non steroidal anti-inflammatory drugs that have been shown to suppress carcinogenesis in both experimental model and epidemiologic studies.

We examined cPLA2α expression in normal, premalignant bronchial epithelial cells and nonsmall cell lung carcinoma (NSCLC) samples using an immunohistochemical staining technique. Included in the current study were 76 NSCLC samples and 52 bronchial biopsy samples obtained.

In the normal bronchial epithelium, cPLA2α expression was found to be completely negative whereas positive cPLA2α expression was limited to a few macrophages, inflammatory cells. There were relatively more cPLA2α positive tumors, as defined by positive staining in >10% of tumor cells 24 of 76 tumors (32%). When tumor types were considered, there were more 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 cPLA2α positive tumors than nonsmokers (23 of 64 tumors in the smokers (36%) vs. 1 of 12 tumors in the nonsmokers (8%); P=0.06).

The results of the current study suggest that cPLA2α expression may not be a useful intermediate biomarker in bronchial chemoprevention trials. Nevertheless, considering the patterns of cPLA2α expression in tumor cells, cPLA2α expression status may be a useful parameter when designing treatment strategies for a subset of NSCLC patients.