Tissue micro array based evaluation of the central DNA double-strand break repair protein KU80 as a prognostic marker in HNSCC

Introduction:

HNSCC represent a heterogeneous entity with regard to localization, outcome and biology. Especially for locally advanced HPV-negative tumors there is still a great need to improve cure rates. So far the HPV-status in OPSCC is the only generally accepted prognostic biomarker and no predictive markers have been established. In a comparison of 39 potential markers, Moeller et al. identified the expression level of the central DNA repair protein KU80 as a strong predictor of overall survival in HPV-negative HNSCC treated by primary radiotherapy (Clin Cancer Res. 2011 Apr 1;17(7):2035 – 43). So far, these data have not been recapitulated. In the present study we have analyzed the expression of KU80 in an HNSCC tissue micro array (TMA) largely composed of tumors treated with surgery and adjuvant (chemo)radiation.

Methods:

A tissue micro array, containing 553 HNSCC samples, was stained for KU80. The immunohistological staining of the tissue samples was scored as negative, weak, moderate or strong by an established algorithm based on staining intensity (0, 1, 2, 3) and the percentage of tumor cells stained.

Results:

In our analyses KU80 expression was not associated with UICC, T or N stage. High expression levels of KU80 is a common feature in HNSCC as 78.4% of tumors in our cohort were scored “strong” whereas only 10.6% of tumors were scored “negative” or “weak”. With regard to survival, we did not observe any statistically significant differences or trends that would suggest a prognostic role of high or low KU80 expression levels in our cohort, neither in early nor in locally advanced stage tumors and irrespective of HPV-status.

Conclusions:

Strong KU80 expression is common in HNSCC but our analyses do not support a role for KU80 expression as a prognostic biomarker.

Publication History

Publication Date:
23 April 2019 (online)