While the gene expression levels of CDKN2A (ranked 71 with COPA and 92 with the GTI) showed a significantly clearer outlier population than GFAP (ranked 29 with COPA and 1866 with the GTI) (Figure 4), GFAP also showed a relatively high level of expression in the normal samples, indicating that this gene may in fact not be relevant for cancer progression. This evidence concerns the gene CDKN2A and cancer.