Elevated levels of hydroxylated phosphocholine lipids in the blood serum of breast cancer patients

The difference in serum phospholipid content between stage‐IV breast cancer patients and disease‐free individuals was studied by employing a combination of chemometric statistical analysis tools and mass spectrometry. Chloroform‐extracted serum samples were profiled for their lipid class composition and structure using precursor ion, neutral loss, and product ion tandem mass spectrometric (MS/MS) scanning experiments. Changes in the relative abundance of phospholipids in serum as a consequence of cancer progression, measured through electrospray ionization (ESI) mass spectrometry of flow‐injected serum samples collected from 25 disease‐free individuals and 50 patients diagnosed with stage‐IV breast cancer, were statistically evaluated using principal component analysis (PCA), analysis of variance (ANOVA) and receiver operating characteristic (ROC) analysis. Lipids whose abundance changed significantly as a consequence of cancer progression were structurally characterized using product ion spectra, and independently quantified using precursor ion scan experiments against an internal standard of known concentration. Phosphocholine lipids that displayed a statistically significant change as a consequence of cancer progression were found to contain an oxidized fatty acid moiety as determined by MS³ experiments. Copyright © 2009 John Wiley & Sons, Ltd.