TNFRSF9 and primary peritoneal carcinoma: Among them, lower BMI (adjusted OR, 0.86; 95% CI, 0.78–0.95; p = 0.005), and the presence of ILA (adjusted OR, 1.07; 95% CI, 1.02–1.13; p = 0.008) were independently associated with PPC occurrence, analyzed by multivariate logistic regression (Additional file 2: Table S2).