Metabonomic models of human pancreatic cancer using 1D proton NMR spectra of lipids in plasma

In this study, we hypothesized that the altered insulin and glucose levels in male pancreatic cancer patients reported in a recent JAMA article would result in an altered lipid profile in the blood of pancreatic cancer patients when compared to controls (Stolzenberg-Solomon et al., 2005). Proton nuclear magnetic resonance (NMR) spectra of human lipophilic plasma extracts were used in order to build partial least squares discriminant function (PLS-DF) models that classified samples as belonging to the pancreatic control group or to the pancreatic cancer group. The sensitivity, specificity, and overall accuracy of the PLS-DF models based on 4 bins were 96%, 88%, and 92%, respectively. The sensitivity, specificity, and overall accuracy of the PLS-DF models based on 5 bins were 98%, 94%, and 96%, respectively. The sensitivity, specificity and overall accuracy of both the 4-bin and 5-bin PLS-DF models dropped only 1–2% during leave-25%-out cross-validation testing. Mass spectrometric profiling of phospholipids in plasma found three phosphatidylinositols that were significantly lower in pancreatic cancer patients than in healthy controls. The cancer models are based upon changes in lipid profiles that may provide a more sensitive and accurate diagnosis of pancreatic cancer than current methods that are based upon a single biomarker.