XRCC6 and colorectal cancer: Lee et al (2005, 2007) reported that negative expression of DNA-PKcs in surgical specimens was significantly associated with tumour progression and poor patient survival rate in gastric cancers. Another report stated that DNA-PK expression of tumour tissues is negatively correlated with lymphatic metastasis, and the survival of patients with colorectal cancer. They argued that Ku70 expression might be a potential indicator for the preoperative evaluation, and prognosis in colorectal cancer (Chen et al, 2008).