Identification of Protein Signature in the Bronchoalveolar Lavage (BAL) Specimen from Lung Adenocarcinoma by Quantitative Proteomics
Qlig Kay Li, Yan Li, Frederic Askin, Edward Gabrielson, Hui Zhang. The Johns Hopkins Medical Institutions and Bayview Medical Center, Baltimore, MD
Background: Bronchoalveolar lavage (BAL) is a commonly used method to recover lung fluid by endobronchoscopy. Proteins in BAL fluid are derived from secretion or leakage of lung parenchymal cells. Levels of these proteins directly reflect the physiological and pathological status of the lung. Recently, quantitative proteomic analysis of BAL specimen has been used to study a variety of benign lung diseases such as asthma, cystic fibrosis, and interstitial lung disease. However, the protein profile of BAL in lung cancer has not been well studied. In this study, we have used newly improved proteomic techniques and quantitatively analyzed the protein profile in BAL specimen from lung adenocarcinoma patients.
Design: Eight BAL specimens were collected from patients with either early or late stage of lung adenocarcinomas. Paraffin-embedded lung adenocarcinoma tissue from eight patients, including four cases each of early stage (stage I/II) and four cases of late stage (stage III/IV) tumors were studied and tumor-matched normal lung tissues included as controls. Tumor cells were microdissected. Peptides from both BAL and tumor cells were extracted and quantified by LC-MS/MS using an LTQ Orbitrap Velos mass spectrometer.
Results: A total of 107 proteins were identified and quantified. Among them, 59 proteins was differentially expressed between BAL samples and tumor tissues (Figure 1). Thirteen proteins were significantly increased and two proteins were significantly decreased in BAL from bronchi with lung adenocarcinoma.
Conclusions: Using highly sensitive proteomic technique, we were able to quantify protein profile in BAL specimen from lung adenocarcinoma. The proteomic analysis of BAL fluid in lung cancer may lead to the discovery of potential tumor-associated as well as non-tumor associated protein biomarkers. They can be used for the early diagnosis of cancer and monitoring the disease progression in lung cancer patients.
Tuesday, March 20, 2012 1:00 PM
Poster Session IV # 310, Tuesday Afternoon