KRAS and duodenal adenocarcinoma: In univariate analysis of primary mortality from duodenal adenocarcinoma, TNM stage II or higher (hazard ratio [HR]: 1.8 × 1010, 95% confidence interval [CI]: not calculable; P < 0.01), undifferentiated (HR: 3.66, CI: 1.43–8.24; P < 0.01), KRAS mutation (HR: 2.44, CI: 1.14–4.99; P = 0.02), gastric phenotype (HR: 2.45, CI: 1.19–5.30; P = 0.01), intestinal phenotype (HR: 0.15, CI: 0.03–0.43; P < 0.01), and PD-L1 status (HR: 2.84, CI:1.37–5.77; P < 0.01) were significant factors (Table 2).