KRAS mutations in primary tumours and post-FOLFOX metastatic lesions in cases of colorectal cancer

British Journal of Cancer, 05/25/2012

Kawamoto Y et al. – Because the mutational statuses of predictive biomarker genes were not altered by FOLFOX therapy, specimens from both primary tumours and post-FOLFOX tumour metastases might serve as valid sources of DNA for known genomic biomarker testing.


  • A total of 63 lesions (23 baseline primary, 18 metastatic and 24 post-treatment metastatic) from 21 patients who were treated with FOLFOX as adjuvant therapy for stage III/IV colorectal cancer following curative resection were examined.
  • The DNA samples were obtained from formalin-fixed paraffin-embedded specimens, and KRAS, NRAS, BRAF and PIK3CA mutations were evaluated.


  • The numbers of primary lesions with wild-type and mutant KRAS codons 12 and 13 were 8 and 13, respectively.
  • The mutational status of KRAS remained concordant between the primary tumours and the post-FOLFOX metastatic lesions, irrespective of patient background, treatment duration and disease-free survival.
  • Furthermore, the mutational statuses of the other genes evaluated were also concordant between the primary and metastatic lesions.

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