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.