EGFR and cancer: Relevant examples include the MAPK signaling pathway, the mTOR signaling pathway, the RAS signaling pathway, the PI3K-Akt signaling pathway, the ErbB signaling pathway, the cGMP-PKG signaling pathway, the HIF-1 signaling pathway, and the cAMP signaling pathway (Figure 4A,B) suggesting that HERVs may be involved in important signaling pathways known as critical in cancer development and progression.