A novel method for screening colorectal cancer by infrared spectroscopy of peripheral blood mononuclear cells and plasma

Background: Early detection of colorectal cancer (CRC) can reduce mortality and morbidity. Current screening methods include colonoscopy and stool tests, but a simple low-cost blood test would increase compliance. This preliminary study assessed the utility of analyzing the entire bio-molecular profile of peripheral blood mononuclear cells (PBMCs) and plasma using Fourier transform infrared (FTIR) spectroscopy for early detection of CRC. Methods: Blood samples were prospectively collected from 62 candidates for CRC screening/diagnostic colonoscopy or surgery for colonic neoplasia. PBMCs and plasma were separated by Ficoll gradient, dried on zinc selenide slides, and placed under a FTIR microscope. FTIR spectra were analyzed for biomarkers and classified by principal component and discriminant analyses. Findings were compared among diagnostic groups. Results: Significant changes in multiple bands that can serve as CRC biomarkers were observed in PBMCs (p = ~0.01) and plasma (p = ~0.0001) spectra. There were minor but statistically significant differences in both blood components between healthy individuals and patients with benign polyps. Following multivariate analysis, the healthy individuals could be well distinguished from patients with CRC, and the patients with benign polyps were mostly distributed as a distinct subgroup within the overlap region. Leave-one-out cross-validation for evaluating method performance yielded an area under the receiver operating characteristics curve of 0.77, with sensitivity 81.5 % and specificity 71.4 %. Conclusions: Joint analysis of the biochemical profile of two blood components rather than a single biomarker is a promising strategy for early detection of CRC. Additional studies are required to validate our preliminary clinical results.