The immunohistochemical expression of DNA-PKcs and Ku (p70/p80) in head and neck cancers: relationships with radiosensitivity

Thomas Björk-Eriksson, Catharine West, Anders Nilsson, Bengt Magnusson, Marie Svensson, Ewa Karlsson, Nicholas Slevin, Rolf Lewensohn, Claes Mercke

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    Purpose: The DNA-PK complex is one of the major pathways by which mammalian cells respond to DNA double-strand breaks induced by ionizing radiation. This study evaluated the relationship between the immunohistochemical expression of the individual components of DNA-PK and cellular radiosensitivity in head and neck cancers.Methods and Materials: Biopsies from patients with previously untreated squamous cell carcinomas of the head and neck were assessed for inherent tumor radiosensitivity measured as the surviving fraction at 2 Gy (SF2) using a soft agar clonogenic assay. Paraffin-embedded tumor material from 64 successfully grown specimens was immunohistochemically stained for expression of DNA-PKcs and Ku (p70/p80). The same tumor material was previously analyzed for the immunohistochemical expression of p53.Results: A significant correlation was found between the degree of expression of DNA-PKcs and Ku (p70/p80) (r = 0.55, p <0.001). There were no overall significant differences in the levels of expression of DNA-PKcs and Ku (p70/p80) in tumors from patients of either sex, different sites, histologies, and stages. No relationship was found between SF2 and the expression of either DNA-PKcs (r = 0.22, p = 0.081) or Ku (p70/p80) (r = 0.064, p = 0.62). Comparison with previous immunohistochemical characterization showed no significant correlations between the expression levels of p53 and either DNA-PKcs (r = 0.093, p = 0.46) or Ku (p70/p80) (r = -0.17, p = 0.17).Conclusions: This study suggests that determining the immunohistochemical expression of DNA-PK in head and neck cancers from multiple sites does not have a role as a predictive assay of tumor in vitro radiosensitivity. Copyright (C) 1999 Elsevier Science Inc.
    Original languageEnglish
    Pages (from-to)1005-1010
    Number of pages5
    JournalInternational Journal of Radiation Oncology Biology Physics
    Issue number4
    Publication statusPublished - 1 Nov 1999


    • DNA-PK
    • Head and neck cancers
    • Ku
    • Radiosensitivity


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