Additionally, the growth factor-receptor tyrosine kinase-phosphatidylinositol 3-kinase signaling pathway (GF-RTK-Ras-PI3K signaling pathway), exhibited opposite regulation patterns compared to the receptor tyrosine kinase (RTK)-phospholipase Cγ (PLCG)-inositol triphosphate receptor (IP3R) signaling pathway, and the integrin αβ (ITGA_B)-Rho GTPase activating protein (RHOGAP)-RhoA signaling pathway, which were down-regulated in the SCLC environment but up-regulated in the AD environment. The gene discussed is RHOA; the disease is Alzheimer disease.