The association between immunoexpression levels of oxidant and antioxidant enzymes and lip squamous cell carcinoma

The aim of this study was to investigate the associations among the immunoexpression levels of manganese superoxide dismutase (Mn-SOD), glutathione peroxidase (GPx), and myeloperoxidase (MPO) in lip squamous cell carcinoma (LSCC) tissues and the clinicopathological characteristics, and prognostic factors in patients with LSCC. The immunoexpression levels of Mn-SOD, GPx, and MPO were examined in 76 LSCC tissue samples using immunohistochemical staining on tissue microarray slides, and compared to those in normal lip mucosa adjacent to venous lakes (normal controls), normal tissue adjacent to corresponding tumors (NTACT), and recurrent tumors. Associations between immunoexpression levels and clinicopathological characteristics were analyzed using the Student's t-test. The prognostic factors were analyzed using Cox regression. The immunoexpression levels of Mn-SOD, GPx, and MPO were significantly different among the normal controls, NTACTs, tumors, and recurrent tumors (Mn-SOD: p = 0.001, GPx: p < 0.001, MPO: p < 0.001). Lower lip cancer was associated with higher Mn-SOD immunoexpression levels (p = 0.04) and probably indicated higher oxidative stress. Lymph node involvement with a lower immunoexpression level of MPO (p = 0.007) indicated compensatory mechanism to attenuate oxidative damage. A low Mn-SOD immunoexpression level was borderline significantly associated with a worse prognosis for disease-specific survival, and it was probably related to a lower capacity for coping with oxidative stress.