PIK3CA and cancer: The cancer-related signaling pathways under diseases of signal transduction by growth factor receptors and second messengers (e.g., signaling by EGFR in cancer, signaling by FGFR in cancer, PI3K/AKT signaling in cancer, signaling by ALK in cancer, signaling by NOTCH1 in cancer, oncogenic MAPK signaling, etc.)were identified as significant pathways from the model-selected genes (Figure 7D).