Mid-Infrared Spectroscopy and Mass Spectrometry Combined to Build a Comprehensive Lung Cancer Fingerprint of Blood Plasma

Infrared (IR) spectroscopy of liquid biopsies shows high potential to become a non-invasive, cost-efficient and fast diagnostic tool for several types of cancers, acute myocardial infarction, Alzheimer's disease as well as possibly other pathologies [1]. However, interpretation of the disease-induced changes in an IR absorption spectrum remains challenging due to high molecular complexity of the samples. Here we perform for the first time Fourier-Transform IR (FTIR) absorption and non-targeted mass spectrometry (MS) based proteomic measurements of the very same set of human blood plasma samples, collected from lung cancer patients and a control group. This combination shows that the IR spectroscopic fingerprint of lung cancer is caused by differential regulation of a number of plasma proteins. Generally, quantitative analysis of cancer-induced changes in blood composition is of paramount importance for cancer diagnostics, and for improving IR spectroscopic fingerprinting approaches in particular.