The immunohistochemical expression of DNA-PKCS and Ku (p70/p80) in head and neck cancers: relationships with radiosensitivity.
West, Catharine M L
Slevin, Nicholas J
AffiliationDepartment of Oncology, Sahlgrenska University Hospital, Gothenburg, Sweden. firstname.lastname@example.org
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AbstractPURPOSE: 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.
CitationThe immunohistochemical expression of DNA-PKCS and Ku (p70/p80) in head and neck cancers: relationships with radiosensitivity. 1999, 45 (4):1005-10 Int. J. Radiat. Oncol. Biol. Phys.
JournalInternational Journal of Radiation Oncology, Biology, Physics
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