Characteristic patterns of functional alterations and distinct oncogenic processes as determinants of oncogenic signature classes (OSCs). (a) The first partition of the tree-like stratification (starting with ‘all tumors’ on the left) identifies two main classes: the M class (green) and the C class (red). We identify 17 oncogenic signature subclasses for the M class (M1–M17) and 14 oncogenic signature subclasses for the C class (C1–C14) (one row per subclass). (b) Each subclass includes subsets of tumors from several cancer types (grayscale heatmap; gray intensity represents the fraction of samples in a particular tumor type (column) and a particular subclass (row)). (c) Tree classification is determined at each level by sets of characteristic functional events (color intensity represents the fraction of samples in a subclass (row) affected by a particular functional event (column)). For functional copy number alterations, we indicate, if present, known oncogenes and tumor suppressors in parentheses, for example, 8q24 (MYC). (d,e) Subclass characteristic events reflect particular cellular processes (color intensity represents the fraction of samples in a subclass (row) affected by alterations to a particular process (column)) (d) and altered pathways involved in each of the processes (e). RTK, receptor tyrosine kinase; DSB, double-strand break. Tumor types abbreviated as in .