Expression of DNA damage response proteins in cervical cancer patients treated with radical chemoradiotherapy

The management of locally advanced cervical cancer has improved significantly with the advent of cisplatin-based chemoradiotherapy (CRT) as the primary treatment regimen. Nevertheless, a significant proportion of patients fail to respond or relapse on this treatment and have a very poor prognosis. Our goal was to determine the prognostic value of a panel of proteins involved in detection and repair of DNA damage.

We performed fluorescence immunohistochemistry, and used software analysis to assess expression of DNA damage response proteins ATM, DNA-PKcs, PARP-1, Ku70 and Ku86 in 117 pre-treatment specimens from patients with locally advanced cervical cancer. We compared expression to clinicopathologic correlates to determine prognostic significance.

Five-year progression-free survival was significantly lower in the low expressors than in high expressors of ATM (35% vs. 58%, p=0.044) and PARP-1 (24% vs. 61%, p=0.003), and showed a trend to significance for DNA-PKcs (30% vs. 60%, p=0.050). Low expression of the same proteins also correlated significantly with lower overall survival. In multivariable analysis, adjusted for FIGO stage and tumor size, low ATM and PARP-1 expression was significantly associated with both poorer progression-free and overall survival. Pairwise analyses indicated that expression levels of these proteins were correlated.

Expression of DNA damage response proteins in cervical cancer is associated with outcome in patients treated with CRT. Immunohistochemical analysis of these proteins may be useful in guiding treatment decisions in such patients.