Plasma lipid profile comparison of five different cancers by nanoflow ultrahigh performance liquid chromatography-tandem mass spectrometry

A comprehensive lipidomic analysis at the molecular level using nanoflow ultrahigh performance liquid chromatography-electrospray ionization-tandem mass spectrometry (nUHPLC-ESI-MS/MS) was performed to elucidate the lipid profiles of patient blood samples from five commonly found cancers (liver, lung, gastric, colorectal, and thyroid), which were then compared with the lipid profiles of healthy controls. From a total of 335 lipids identified and quantified, 50 high abundance lipids showing significant changes (>2-fold and p < 0.01) in at least one of the five cancers (vs. controls) were analysed. Lipid species were found to be significantly associated with more than one type of cancer; the numbers of lipid species found as significantly changed in all five, four, three, two, and one type of cancer were 1, 8, 8, 15, and 17, respectively. Among these, the high abundance phosphatidylethanolamine species, including lysophosphatidylethanolamine and PE plasmalogen, was significantly low in four cancer types, but was high in thyroid cancer. Receiver operating characteristic analysis resulted in the selection of lipids specific to each cancer: liver (four phosphatidylinositols and diacylglycerol 16:1_18:0), gastric (phosphatidylcholine 34:2, 36:3, and 36:4, and lysophosphatidic acid 18:2), lung (lysophosphatidylinositol 16:0, sphingomyelin d18:1/20:0, and triacylglyceride 50:1 and 54:4), and thyroid (lysophosphatidylinositol 18:0 and 18:1). Our results provide a basis for future validation of cancer-specific lipid markers with high diagnostic ability.