XCR1 and head and neck squamous cell carcinoma: Further Cox proportional hazards analysis showed that XCR1 was a low-risk gene in SKCM (skin cutaneous melanoma, p < 0.001), LIHC (liver hepatocellular carcinoma, p < 0.001), HNSC (head and neck squamous cell carcinoma, p < 0.001), LUAD (lung adenocarcinoma, p = 0.003), ESAD (esophageal adenocarcinoma, p = 0.005), KIRC (kidney renal clear cell carcinoma, p = 0.012), BRCA (breast invasive carcinoma, p = 0.019), SARC (sarcoma, p = 0.021), CESC (cervical squamous cell carcinoma and endocervical adenocarcinoma, p = 0.034), and ESCA (esophageal carcinoma, p = 0.044) (Figure 1B).