Two-way, unsupervised hierarchical clustering representing the 60 tumor cell lines (vertical axis) and the analyzed total, phospho- and cleaved proteins (horizontal axis). Two-way, unsupervised hierarchical clustering representing the 60 tumor cell lines (vertical axis) and the analyzed total, phospho- and cleaved proteins (horizontal axis). The clustering reveals the formation of 3 major groups (A, B, and C) that are largely independent upon the cell line origin classification but are defined by the underpinning pathway activation. Within the heatmap, red color represents higher levels of relative activity/expression; black represents intermediate levels, and green represents lower levels of relative activity/expression. The 60 tumor cell lines have been highlighted by colors indicating the tissue origin: orange – kidney, blue – lung, pink – breast, red – blood, green – colon, brown – prostate, purple – ovary, black – skin, and gray – central nervous system. Giulia Federici et al. Mol Cancer Res 2013;11:676-685 ©2013 by American Association for Cancer Research