Fig. 3

Metabolite levels in plasma on the day of surgery compared to years before diagnosis. (a) An overview of repeated plasma samples, collected up to 12 years before glioma diagnosis (pre-dx) and on the day of surgery (OP), from the same individuals (n = 40). (b) Summary of the four generated OPLS-models. Bold text highlight significant OPLS-EP model (n = 27 pairs) with satisfactory Q² value and P < 0.05. (c) Cross-validated scores of the four OPLS-models shown in (b). (d–g) Volcano plots of the 134 metabolites and 22 unidentified molecular features for the repeated plasma samples modeled in (b). Effect sizes are shown as log₂ fold change, and statistical significance by -log₁₀ P-value for individual metabolites using model loadings w. Metabolites with significantly higher (blue) or lower (red) levels in surgery samples are named. (h) Boxplots of metabolites that were only detected in surgery samples.