The boxplots analyzes of FABP4 and MMP9 expression levels from the GSE datasets or the RT-Q-PCR analyzes showed that some NAFL and NASH patients had high or low FABP4 and MMP9 mRNA expression levels (Figs. 4B, 5B,H) and a misclassification of patients from the Validation cohort was observed in each group of NAFL and NASH patients as shown by the CART (characteristic and regression tree) analysis (Supplementary Fig. S7C,D, respectively). Here, MMP9 is linked to metabolic dysfunction-associated steatohepatitis.