Fig. 1: Liver metastases show reduced variation along the principal components that separate CMS1 and CMS3 primary tumors from CMS2 and CMS4.

The lower triangle of the scatterplot matrix depicts the first five principal components (PCs) for primary CRCs, with samples colored according to CMS (dark gray = not confidently classified). The diagonal windows show the percentage of total variance explained by each PC (bottom) and the Pearson correlations (r) between the indicated PC and single-sample gene set scores (GSVA) for the top-4 correlated gene sets among primary tumors (hatched bars; blue and red represent negative and positive correlations, respectively). Correlations among liver metastases are shown for comparison (non-hatched bars). The upper triangle represents the transpose of the lower triangle with the metastatic samples (light gray) superimposed by projections onto the same PCs. The black contour lines represent the 50%, 75%, and 95% two-dimensional density estimates. The presented data are from the in-house series, and results from the same analysis of the external validation data set are included in Supplementary Fig. 2.