Abstract: BACKGROUND AND AIM: To evaluate the polymeric immunoglobulin receptor/secretory component(pIgR/SC) protein levels in the bronchoalveolar lavage fluid (BALF) samples derived from lung cancer patients, and explore its clinical significance. MATERIALS AND METHODS: BALF samples were obtained from 52 lung cancer patients from the affected side and also the matched healthy side in 18 patients, and were analyzed for the pIgR/SC protein levels by enzyme_linked immunosorbent assay (ELISA). RESULTS: In the 18 cases, the mean pIgR/SC value in BALF of the affected side was significantly greater than that of the matched healthy side(P=0.019). In 52 lung cancer patients, the protein level of pIgR/SC in BALF was significantly higher in adenocarcinoma patients than that in squamous cell carcinomas (P=0.014). The pIgR/SC levels in BALF of patients with squamous cell carcinoma with lymph node invasion were significantly higher than that of patients without (P=0.012). CONCLUSION: The high level of pIgR/SC in airways is likely to indicate host response to tumor carcinogenesis. Furthermore the pIgR/SC level in BALF may reflect the histological difference of lung cancers. In squamous cell carcinoma, pIgR/SC may be involved in lymph node invasion.

Key words: pIgR/SC, lung cancer, bronchoalveolar lavage fluid, ELISA