Our study revealed that low CAIX expression was associated with the presence of lymph node metastases (OR = 0.31, 95% CI = 0.15–0.62, P = 0.0009, Figure 5) and distant metastases (OR = 0.66, 95% CI = 0.46–0.96, P = 0.03, Figure 6). The gene discussed is CA9; the disease is metastatic malignant neoplasm in the lymph nodes.