SDHA and metastatic malignant neoplasm in the lymph nodes: Factors negatively associated with OS were T stage (Hazard ratio: 2.218, 95% CI: 1.229 − 4.001, P = 0.008), lymph node metastasis (Hazard ratio: 1.831, 95% CI: 1.076 − 3.115, P = 0.026), high tumor expression of SDHA (Hazard ratio: 4.157, 95% CI: 1.657 − 10.432, P = 0.002), and low SDHB expression (Hazard ratio: 3.223, 95% CI: 1.295 − 8.025, P = 0.012).