Each subtype was characterized by a distinct set of upregulated (highest quartile) and downregulated (lowest quartile) phosphoproteins involved in key cancer signaling pathways, such as PI3K-Akt signaling, ErbB signaling, MicroRNA signaling, and focal adhesion (Table 1, Fig. 2B–E, Supplemental Fig. 1). Here, EGFR is linked to cancer.