NOX4 and gastric adenocarcinoma: Next, based on their mRNA expression levels and the coefficients from LASSO Cox regression analysis, each STAD patient in the TCGA database was assigned a risk score using the following formula: Risk Score = SPARC*0.119965 + NOX4*0.113284 + SLC1A5*(-0.102689) + GPX3*0.096876 + CP*0.083136 + ZFP36*0.077765 + ATF3*0.031323.