P-values of angiogenesis and ten most significant terms for glioblastoma samples over time A) The red line shows the change in p-value of the angiogenesis term from 0.024 (2007) to 1.07x10-8 (2012). The grey lines are the p-values for the ten most significant terms in enrichment analysis from 2012 traced through time (see Table 1). The vertical axis is on a log scale. Some lines start after 2004 or end before 2012 due to filtering in the enrichment analysis (only terms annotated to between 3 and 500 genes). The final p-values have had a Bonferroni multiple-testing correction applied. B) The same as A but using the most significant terms from enrichment analysis done with 2006 versions of the ontology and annotations.