Fig. 1.

Data collection and analysis. A, Histogram of the log-intensities of polar metabolites measured by targeted LC-MS/MS across 17 samples. B, Histogram of coefficient of variation (CV) of measured metabolites across 17 samples. C, Scatterplot of average metabolite intensities of control samples (x axis) against malignant glioma (MG) samples. One hundred and eighteen metabolites lie above the line and 71 below the line showing a statistically significant difference. D, Comparison of histogram densities of the log-intensities of measured metabolites of MG samples (blue) and control samples (gray). Each histogram was scaled by dividing values by the total count for each to account for differences in number of data points. Kullback-Leibler (K-L) divergence between the distributions was measured to be 0.0017. E, Comparison of histogram densitry of the CV (standard deviation/mean) of measured metabolites of MG samples (blue) and control samples (gray). K-L divergence between the distributions was observed to be 0.29.