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Updated: Mar 15, 2026

Endobronchial Ultrasound-guided Intratumoral Injection of Cisplatin for the Treatment of Isolated Mediastinal Recurrence of Lung Cancer
Published on: February 12, 2017
Delayed DNA double-strand break repair following platin-based chemotherapy predicts treatment response in head and
S A Bhide1,2,3, K Thway1,2, J Lee3
1Head and Neck unit, The Royal Marsden Hospital, Fulham Road, London SW3 6JJ, UK.
Introduction:
The aim of this study was to investigate if defective repair of DNA double-strand break (DSB) in head and neck squamous cell carcinoma (HNSCC) could be used as an early predictor of treatment response.
Methods:
Tumour biopsy 24-36 h following induction chemotherapy (IC) and pre-treatment biopsies were stained for RAD51 and geminin (S-phase marker) for immunofluorescence in patients with HNSCC. The difference between RAD51 score (percentage of geminin-positive cells that were also positive for RAD51) was calculated for the two specimens. Tumours with a percentage difference of⩽10% were deemed to have repaired IC-induced DSBs, and were classified as 'RAD51 negative'. Response at 3 months post treatment and human papilloma virus (HPV) status were assessed.
Results:
Thirteen pairs of samples were available for analyses. Three samples were classified as RAD51 negative and 10 as RAD51 positive at 24 h post IC. All of the three patients with tumours classified as RAD51 negative had partial response or progressive disease and the 10 patients with tumours deemed RAD51 positive had a complete response. 100% of the HPV-positive tumours were RAD51 positive and had a complete response.
Conclusions:
We have demonstrated that impaired DSB DNA repair may underlie enhanced treatment sensitivity of HPV-positive HNSCC and repair capacity following platinum-induced DNA damage predicts response in HNSCC. This has potential as a biomarker for patient selection in trials of DNA damage response pathway modulation.
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