Fig. 2

Multivariate statistical analysis for discrimination model construction and differential compounds screening. A: Score scatter plot for PCA model of amino acids metabolic profile in plasma samples of training set presented a separation trend between CRC and HV[R2X(cum) = 0.499, Q2(cum) = 0.292]. B: Score scatter plot for OPLS-DA model of amino acids metabolic profile in CRC and HV plasma samples of training set, and good separation was obtained [R2X(cum) = 0.414, R2Y(cum) = 0.853, Q2(cum) = 0.834]. C: The plot of response permutation testing proved the reliability of OPLS-DA model (n = 200, HV). D: Coefficient column plot for OPLS-DA of CRC vs. matched control, illustrating changes of amino acids in CRC occurrence