Proteomic changes between primary tumors and matched distant metastases of lung adenocarcinomas

Lung cancer is the leading cause of cancer-related deaths worldwide and lung adenocarcinoma is the most common form of lung cancer. Genomic studies of lung adenocarcinoma (LUAD) have advanced our understanding of the disease's biology and accelerated targeted therapy. However, the proteomic characteristics of LUAD are still insufficiently understood. Prognosis for lung cancer patients remains poor and is strongly related to the stage of disease at the time of diagnosis. Therefore, our study focuses on metastasis formation in LUAD. We performed high-performance liquid chromatography (HPLC) and electrospray ionization tandem mass spectrometry (ESI-MS/MS) on a total of 40 FFPE samples and compared proteomic profiles of primary tumors to those of matched distant metastases. Using differential expression analysis and unsupervised clustering we identified candidate proteins playing a role in metastatic spread. Selected proteins were validated by immunoblotting. Our findings give a better understanding of tumor progression and metastasis formation in LUAD and might help to develop biomarker specific therapy.