For choline metabolism in the cancer pathway, SOS Ras/Rho guanine nucleotide exchange Factor 2 (SOS2) was significantly upregulated, and receptor-induced membrane recruitment of the cytoplasmic protein SOS led to Ras/MAPK cascade activation [65], which may be one of the ways that BRECs activate the MAPK pathway in the face of low-pH stress. The gene discussed is SOS2; the disease is cancer.