Manganese superoxide dismutase expression correlates with p53 status and local recurrence of cervical carcinoma treated with radiation therapy.
Manganese superoxide dismutase (Mn-SOD) inactivates the radiation effect by removal of radiation-induced toxic superoxide radicals. The purpose of this study was to assess the correlation among Mn-SOD, radiation sensitivity, and prognosis following radiation therapy. The Mn-SOD, p53 oncoprotein, and c-erbB-2 oncoprotein expressions in 52 specimens from patients with cervical cancer treated with radiation therapy were investigated immunohistochemically. The frozen sections were stained using antihuman Mn-SOD, anti-p53 monoclonal antibodies, and anti-c-erbB-2 oncoprotein polyclonal antibody followed by the avidin-biotin peroxidase complex method. Correlations among Mn-SOD expression, prognosis, and failure patterns were analyzed. Additionally, correlations between p53 and c-erbB-2 oncoproteins and Mn-SOD expression were investigated. Positive expression of Mn-SOD in cervical carcinoma was 48.1%. No significant difference in positivity of Mn-SOD expression was noted according to stage and histological subtypes. The 5-year survival rate of Mn-SOD-positive patients was 42.5 %, significantly poorer than the 77.0% of Mn-SOD-negative patients (P < 0.05). Analysis of the failure patterns revealed that patients with Mn-SOD expression showed a significantly higher incidence of local recurrence than those without. However, there was no difference in distant metastasis between them. Although both p53 and c-erbB-2 oncoprotein expressions were significantly associated with the prognosis of the same patients, Mn-SOD expression was associated with p53 oncoprotein expression but not with that of c-erbB-2 oncoprotein. Our results demonstrate that the Mn-SOD level of cancer cells is correlated with local control and is an important prognostic factor in radiation therapy for cervical cancer. The Mn-SOD level may help explain the intrinsic radiosensitivity of cervical cancer cells.
Nakano
T
T
Division of Radiation Medicine, National Institute of Radiological Sciences, 9-1, Anagawa-4-chome, Inage-ku, Chiba-shi, Japan.
Oka
K
K
Taniguchi
N
N
D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism*; D015996:Survival Rate; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D002583:Uterine Cervical Neoplasms / Q000378:metabolism* / Q000532:radiotherapy*
D009363:Neoplasm Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D013482:Superoxide Dismutase; D016159:Tumor Suppressor Protein p53