Figure 1. Comparison of serum metabolite levels between colorectal cancer patients and healthy volunteers.

The mean fold changes in the levels of 107 metabolites observed in a comparison between colorectal cancer patients (N = 60) and healthy volunteers (N = 60) (training set) are shown in Figure 1. In GC/MS analysis, multiple peaks are sometimes detected for a particular metabolite due to TMS-derivatization, isomeric form, etc. In such cases, the peak that most reflected the level of the metabolite was adopted for the subsequent evaluation. In addition, each metabolite had the term ‘_1’, ‘_2’, or ‘(-TMS)’ added to the end of its name, as described in a previous report [7]. This figure does not include background metabolites or minor peak-derived metabolites.