Using immunohistochemical analysis of Ku70 and Ku80 on primary tumour biopsies from stage I–III cervical cancer patients, Wilson et al (2000) showed that all tumours with a low frequency of Ku70 or Ku80 immunopositive cells (<60%) were radiosensitive in a clonogenic assay. The gene discussed is XRCC6; the disease is cervical carcinoma.