Low expression of Ku70/80, but high expression of DNA-PKcs, predict good response to radiotherapy in early breast cancer

  • Authors:
    • Karin Söderlund Leifler
    • Siv Queseth
    • Tommy Fornander
    • Marie Stenmark Askmalm
  • View Affiliations

  • Published online on: December 1, 2010     https://doi.org/10.3892/ijo_00000808
  • Pages: 1547-1554
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Abstract

The purpose was to study the prognostic and predictive roles of DNA protein kinase catalytic subunit (DNA-PKcs), Ku70/80 and p53 for the effect of radiotherapy in breast cancer patients. Protein expressions of Ku70/80, DNA-PKcs and p53 were examined using immunohistochemistry in tumours from 224 breast cancer patients, who were randomised to receive post-operative radiotherapy or adjuvant chemotherapy (cyclophosphamide, methotrexate, 5-fluorouracil). One hundred and twenty-nine (60%) of the tumours had low expression of Ku70/80, 122 (57%) had low expression of DNA-PKcs and 65 (30%) had altered p53 expression. None of the proteins were indicative to the prognosis of local recurrence-free survival. Even though the expression of Ku70/80 and DNA-PKcs correlated well, they were not associated with treatment outcome in the same way. Low expression of Ku70/80 predicted good effect of radiotherapy (RR=0.31, 95% CI 0.13-0.76, p=0.01). In contrast, the greatest benefit of radiotherapy over chemotherapy was seen in patients with high DNA-PKcs expression (RR=0.25, 95% CI 0.07-0.84, p=0.02). Altered p53 expression predicted poor response to radiotherapy. We believe that the results reflect the different roles of DNA-PKcs and Ku70/80 in repair and cell death regulation after DNA damage. These differences could be of importance when developing drugs that target DNA repair.

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December 2010
Volume 37 Issue 6

Print ISSN: 1019-6439
Online ISSN:1791-2423

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Spandidos Publications style
Söderlund Leifler K, Queseth S, Fornander T and Askmalm MS: Low expression of Ku70/80, but high expression of DNA-PKcs, predict good response to radiotherapy in early breast cancer. Int J Oncol 37: 1547-1554, 2010
APA
Söderlund Leifler, K., Queseth, S., Fornander, T., & Askmalm, M.S. (2010). Low expression of Ku70/80, but high expression of DNA-PKcs, predict good response to radiotherapy in early breast cancer. International Journal of Oncology, 37, 1547-1554. https://doi.org/10.3892/ijo_00000808
MLA
Söderlund Leifler, K., Queseth, S., Fornander, T., Askmalm, M. S."Low expression of Ku70/80, but high expression of DNA-PKcs, predict good response to radiotherapy in early breast cancer". International Journal of Oncology 37.6 (2010): 1547-1554.
Chicago
Söderlund Leifler, K., Queseth, S., Fornander, T., Askmalm, M. S."Low expression of Ku70/80, but high expression of DNA-PKcs, predict good response to radiotherapy in early breast cancer". International Journal of Oncology 37, no. 6 (2010): 1547-1554. https://doi.org/10.3892/ijo_00000808