Figure 2

Principal component analysis (PCA) of colon cancer (dots) and normal colon tissues (circles). A linear combination of the first and the second principal component leads to a nearly perfect separation of carcinomas from normal tissues (A). A single misassigment is found: one tumor clusters within the normal tissue group. Box plots show the separation of cancer and normal tissues by the first and the second principal component (B, C). P-values shown are from Welch's t-test after Bonferroni correction for multiple testing. The boundaries of boxes and whiskers mark the 5^th, 25^th, 50^th, 75^th, and 95^th percentile.