Proteomic Biomarkers of Non-Small Cell Lung Cancer Patients

Lung cancer is a disease with a very low 5-year survival rate (6–13%) worldwide. The most frequently diagnosed histological type of this cancer is non-small cell lung cancer (NSCLC). Poor prognosis for lung cancer—including NSCLC—is mainly related to the fact that patients are diagnosed in the advanced stages of the disease. The aim of this study is to summarize data that concerns new directions of research regarding diagnostic biomarkers that could be used to support the routine diagnosis of this cancer. In recent years, proteomic analysis has become an important tool for cancer biology research, complementing genetic analysis. Among the numerous methods of proteomic analysis, mass spectrometry techniques enable the extremely accurate qualitative and quantitative identification of hundreds of proteins in small volumes of various biological samples. Such analyses may soon become the basis of improvement in lung cancer diagnostic procedures. This study presents the latest reports in proteomic research concerning the diagnosis of NSCLC. New potential proteomic biomarkers, whose presence indicates the development of a neoplastic process at an early stage, are presented. We describe biomarkers whose altered expression levels correlate with different stages of cancer. We also present protein biomarkers that help differentiate NSCLC subtypes. In the clinical workup of NSCLC patients, it is important not only to make an early diagnosis, but also to monitor the development of the neoplastic disease. Considering this fact, we also present examples of biomarkers whose abnormal expression may indicate a high risk of metastasis to the lymph nodes. This paper also emphasizes the need to conduct further research that would confirm the usefulness of the described biomarkers in clinical practice.