RESUMEN
<p><b>OBJECTIVE</b>To investigate the expression of manganese superoxide dismutase (MnSOD) and to determine the relationship between MnSOD expression and clinicopathological features, biological behaviors in esophageal carcinoma.</p><p><b>METHODS</b>Immunohistochemistry (SP) and RT-PCR were respectively used to detect the expression of MnSOD in 45 specimens of esophageal carcinoma tissues and normal esophageal mucosa (5 cm distant from the margin of cancer).</p><p><b>RESULTS</b>The positive rate of MnSOD protein expression was 31.1% in esophageal carcinoma tissues, significantly lower than 86.7% in the normal tissues (P < 0.05). The expressions of MnSOD mRNA and protein were significantly correlated with the lesion length, depths of invasion and histological grade (P < 0.05), but not with lymph node metastasis, lesion site and gross type of the tumor (P > 0.05). The relative content of MnSOD mRNA was (0.310 ± 0.036) and (0.482 ± 0.053) in the cancer and normal tissues, respectively, with a significant difference between the two groups (P < 0.05). The relative content of MnSOD mRNA was significantly related to lesion length, depths of invasion and histological grade (P < 0.05), but not correlated with lymph node status, lesion site and gross type of the tumor (P > 0.05).</p><p><b>CONCLUSION</b>The expression of MnSOD protein and mRNA is decreased in esophageal carcinoma, suggesting that MnSOD gene may be closely associated with the carcinogenesis and the degree of malignancy. Detection of MnSOD expression may be useful in diagnosis, treatment and prognosis of esophageal carcinoma.</p>