Fig. 2

Analysis of multivariate data from LC-MS and GC-MS data. (A) The plot of the OPLS-DA score for the GC-MS data from non-pCR and pCR groups at the time point of baseline. (B) The plot of the OPLS-DA score for the LC-MS data from non-pCR and pCR groups at the time point of baseline. (C) Volcano diagram depicting the differentially expressed metabolites (DEMs) in the non-pCR and pCR groups at the time point of baseline. DEMs with VIP values higher than 1.0 and p-values lower than 0.05 were considered significant. Red and blue dots indicate up- and down-regulated metabolites, respectively. (D) Heatmap depicting the 100 pre-therapeutic DEMs between non-pCR patients and pCR groups according to metabolite class. Each column represents a subject and each row represents a metabolite. (E) The distribution of the counts of DEMs among the different groups. Group A, B, C, non-pCR patients, N = 19; group D, E, F, pCR patients, N = 21. Group A and D, at the time point of baseline; Group B and E, at the time point 2 cycles of neoadjuvant treatment; Group C and F, at the time point after 6 cycles (before surgery) of neoadjuvant treatment