Association of increased prostaglandin E2 content in bronchoalveolar lavage fluid and intrathoracic malignancy

Prostaglandin E2 (PGE2), a metabolite of arachidonic acid, plays an important role in immunoregulation. We have previously reported an increased PGE2 content in bronchoalveolar lavage fluid (BALF) in 18 patients who had primary lung cancer as compared with 6 patients who had benign lung diseases and 10 normal smokers. In this article, we report our further observation, including additional 73 patients with primary lung cancer, 11 patients who had carcinoma other than lung cancer with and without lung metastases, and 24 patients with various benign lung diseases. Prostaglandin E2 content of BALF in patients with primary lung cancer and patients with extrathoracic cancer with lung metastases was markedly increased to 283.7 +/- 423.8 and 278.3 +/- 303.4 pg/ml, respectively. In contrast, patients who had extrathoracic cancer without lung metastases and patients with benign lung diseases had PGE2 content in BALF of 22.6 +/- 6.6 and 27.2 +/- 12.4 pg/ml, respectively. Values between the subgroups of patients with lung cancer (primary and metastatic) and patients with benign diseases or extrathoracic cancer without lung metastasis were significantly different (p < .001). Follow up of eight patients who successfully underwent surgical resection of cancer showed decreased levels of PGE2 in all but two patients. Although the exact cause and mechanism of the observed increase of PGE2 in BALF of patients with lung cancer are not clear at this point, current study together with our previous observations clearly indicates that the presence of lung cancer, both primary and metastatic, is associated with an elevated PGE2 content of BALF. The clinical significance of this observation is not known. However, an increased amount of PGE2 in BALF might adversely affect the course of lung cancer, because PGE2 is a down regulator of immune response against infection and neoplasm. Further investigations into the mechanism(s) and the role of PGE2 in BALF are warranted.