Expression of genes involved in repair of DNA double-strand breaks in normal and tumor tissues.
BACKGROUND
DNA double-strand breaks (DSB) are the major lethal lesions induced by ionizing radiation. The capability for DNA DSB repair is crucial for inherent radiosensitivity of tumor and normal cells. DNA-PKcs, Ku 70, Ku 85, Xrcc4, and Nbs1 play a critical role in DNA DSB repair.


METHODS
We immunohistochemically investigated the expression of DNA-PKcs, Ku 70, Ku85, Xrcc4, and Nbs1 in 134 specimens from various normal and tumor tissues with different radiosensitivity.


CONCLUSIONS
Immunopositivity to Ku70, Ku85, DNA-PKcs, Xrcc4, and Nbs1 was found in all tumor tissues examined. The staining for Ku70, Ku85, and DNA-PKcs was nuclear; but, for Xrcc4 and Nbs1, it was nuclear and cytoplasmic. There were no apparent differences in the expression of these five proteins among cancerous tissues and the corresponding normal tissues. No apparent differences in nuclear staining intensity were detected in the expression of these five proteins among tumor tissues with different radiosensitivity, although non-Hodgkins' lymphoma (B or T cell) tended to show a lower expression than the others. The stromal cells generally expressed these five proteins at much lower frequency than either tumor or epithelial cells in both tumor and normal tissues.
Sakata
K
K
Department of Radiology, Sapporo Medical University, School of Medicine, Sapporo, Japan. sakatako@sapmed.ac.jp
Matsumoto
Y
Y
Tauchi
H
H
Satoh
M
M
Oouchi
A
A
Nagakura
H
H
Koito
K
K
Hosoi
Y
Y
Suzuki
N
N
Komatsu
K
K
Hareyama
M
M
D034961:Antigens, Nuclear; D004265:DNA Helicases; D004260:DNA Repair / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D000072200:Ku Autoantigen; D008228:Lymphoma, Non-Hodgkin / Q000378:metabolism / Q000532:radiotherapy; D009363:Neoplasm Proteins / Q000378:metabolism*; D009369:Neoplasms / Q000378:metabolism* / Q000532:radiotherapy; D009687:Nuclear Proteins / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism; D011836:Radiation Tolerance / Q000235:genetics
D034961:Antigens, Nuclear; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D009842:Oligopeptides; C101467:XRCC4 protein, human; C079676:lysyl-arginyl-alanyl-lysyl-alanyl-lysyl-threonyl-threonyl-lysyl-lysyl-arginine; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen