EGFR and cancer: The functional enrichment analysis identified several pathways notoriously known to be crucial in cancer development and progression such as MAPK, PI3K/AKT/mTOR, RAS, ErbB, and HIF-1 signaling pathways as well as pathways involved in adaptive immunity in both TCGA-LUAD and TCGA-LUSC cohorts (Figure 4A,B).