Figure 2. The unique metabolic features of male SCLC compared to NSCLC and controls. (A, B) Multivariate analysis of metabolomic data using PLS-DA resulted in a clear separation of metabolic features among SCLC, NSCLC and the control group in males. (A) 2-D plot. (B) 3-D plot. (C) The top 15 most differential metabolites in male patients with SCLC revealed by VIP analysis. VIP>1.5 was considered as statistically significant. The VIP results were also verified by univariate ANOVA analysis. (D) The top pathways disturbed in male SCLC patients. Abbreviations: IMP = inosine monophosphate; Cer = Ceramide; SM = Sphingomyelin; PI = Phosphatidylinositol; NSCLC = non-small cell lung cancer; PLS-DA = partial least square discriminant analysis; SCLC = small cell lung cancer; VIP = variance in projection.