Plasma secretory phospholipase A2-IIa as a potential biomarker for lung cancer in patients with solitary pulmonary nodules.

BACKGROUND: Five-year survival for lung cancer has remained at 16% over last several decades largely due to the fact that over 50% of patients are diagnosed with locally-advanced or metastatic disease. Diagnosis at an earlier and potentially curable stage is crucial. Solitary pulmonary nodules (SPNs) are common, but the difficulty lies in the determination of which SPN is malignant. Currently, there is no convenient and reliable biomarker effective for early diagnosis. Secretory phospholipase A2-IIa (sPLA2-IIa) is secreted into the circulation by cancer cells and may allow for an early detection of lung cancer. METHODS: Plasma samples from healthy donors, patients with only benign SPN, and patients with lung cancer were analyzed. Expression of sPLA2-IIa protein in lung cancer tissues was also determined. RESULTS: We found that the levels of plasma sPLA2-IIa were significantly elevated in lung cancer patients. The receiver operating characteristic curve analysis, comparing lung cancer patients to patients with benign nodules, revealed an optimum cutoff value for plasma sPLA2-IIa of 2.4 ng/ml to predict an early stage cancer with 48% sensitivity and 86% specificity and up to 67% sensitivity for T2 stage lung cancer. Combined sPLA2-IIa, CEA, and Cyfra21.1 tests increased the sensitivity for lung cancer prediction. High level of plasma sPLA2-IIa was associated with a decreased overall cancer survival. sPLA2-IIa was overexpressed in almost all non-small cell lung cancer and in the majority of small cell lung cancer by immunohistochemistry analysis. CONCLUSION: Our finding strongly suggests that plasma sPLA2-IIa is a potential lung biomarker to distinguish benign nodules from lung cancer and to aid lung cancer diagnosis in patients with SPNs.

The value of BAL fluid LDH level in differentiating benign from malignant solitary pulmonary nodules.

PURPOSE: Serum lactate dehydrogenase (LDH) concentration is an indicator of tissue injury. It may be locally secreted in some conditions. This study was performed in order to investigate the value of LDH levels in bronchoalveolar lavage fluid (BALF) in the differentiation of a bening, from a malignant solitary pulmonary nodules (SPN) and to assess its relationship with serum LDH levels. METHODS: The study was a prospective clinical study. It included 59 patients with a SPN. They underwent bronchoscopy with bronchoalveolar lavage (BAL). Both total serum and BAL LDH levels were measured. RESULTS: BALF LDH level was increased in all patients with malignant SPN. The mean BALF LDH level was significantly higher in patients with malignant SPN (342.23 +/- 89.98) as compared to the benign ones (17.62 +/- 7.90) (P < 0.001). There was no correlation between BALF LDH and serum LDH level in patients with SPNs (P = 0.595). CONCLUSION: BALF LDH levels are increased in patients with malignant SPN, but had no significant rise in benign SPN. This factor is useful in differentiating the benign SPNs from malignant SPNs.