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Role of metallothioneins in irradiated human rectal carcinoma
Author(s) -
Bouzourene Hanifa,
Chaubert Pascal,
Gebhard Sandra,
Bosman Fred T.,
Coucke Philippe
Publication year - 2002
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.10780
Subject(s) - radioresistance , radiation therapy , immunohistochemistry , medicine , pathology , biopsy , carcinoma , colorectal cancer , cancer , in vivo , cancer research , histology , biology , microbiology and biotechnology
BACKGROUND Metallothioneins (MT) are low‐molecular weight, metal‐binding proteins that play a role in cellular proliferation and differentiation, as well as in cellular defense mechanisms. They act as scavengers of free radicals produced by irradiation. A number of in vitro and in vivo studies have linked overexpression of cellular MT with tumor cell resistance to radiation. This is the first study that investigates whether MT expression is involved in the radioresistance of rectal carcinoma. METHODS Using a mouse monoclonal antibody, MT expression was analyzed by immunohistochemistry on surgical samples ( n = 85) from 85 patients with locally advanced rectal carcinoma who were treated preoperatively with a hyperfractionated and accelerated radiotherapy schedule and on tumor biopsies ( n = 13) obtained before treatment. The potential correlations between MT expression and pathologic variables and survival were examined. RESULTS MT were expressed strongly in both the cytoplasm and nucleus of tumor cells in 7 biopsy and 42 surgical samples. A comparison of MT expression in biopsy and surgical specimens showed that MT expression did not change after irradiation in most cases. Against all expectations, MT were expressed more frequently in tumors from responders than in those from the nonresponders ( P = 0.02). There was no correlation between MT expression and tumor stage, histology after radiotherapy, or survival. CONCLUSION These findings do not support the hypothesis that MT overexpression at the end of radiotherapy is a marker for radiation resistance. Cancer 2002;95:1003–8. © 2002 American Cancer Society. DOI 10.1002/cncr.10780