Fig. 1

Metabolomics and GEO analyses indicate high G6PD expression is associated with poor prognosis in MM. a Score plot of OPLS-DA based on data from ESI⁻ mode in healthy people and newly diagnosed MM patients. b A volcano plot showed that there were 53 differentially expressed substances, including 46 upregulated and 7 downregulated substances in the serum of the MM group compared with the Ctrl group. c KEGG pathway enrichment analysis revealed the perturbed pathways. 1. Biosynthesis of unsaturated fatty acids. 2. Linoleic acid metabolism. 3. Arachidonic acid metabolism. 4. Pentose phosphate pathway. 5. Citrate cycle (TCA cycle). 6. Fatty acid biosynthesis. 7. Butanoate metabolism. d ELISA analysis showed serum DHEAS levels in healthy people and newly diagnosed MM patients. e Diagrammatic sketch of DHEA and its transformation to the more stable sulfate ester DHEAS by HST. f mRNA levels of G6PD were significantly increased in MM samples based on the one-way ANOVA. g, h Kaplan–Meier analysis showing the association between G6PD expression with OS in TT2 (g) and HOVON65 (h) cohorts based on a log-rank test