Figure 2. Discovery and validation of the serum metabolite markers. (A) Venn graph displayed the number of discriminating metabolite ions selected in the development and validation cohort and the number of common ions; (B) The most significantly metabolite ions with the largest fold changes were highlighted by a volcano graph; (C) The top 10 metabolites’ relative expression levels were visualized by a heatmap; (D) Two typical serum lipids relative intensities in serum displayed by box plots. (E) Their spatial distribution in the intact OSCC tissues were visualized and compared by DESI-MSI under guidance (F) of H&E staining images.