Microsatellite instability and mutations in BRAF and KRAS are significant predictors of disseminated disease in colon cancer.

Abstract

BACKGROUND:

Molecular alterations are well studied in colon cancer, however there is still need for an improved understanding of their prognostic impact. This study aims to characterize colon cancer with regard to KRAS, BRAF, and PIK3CA mutations, microsatellite instability (MSI), and average DNA copy number, in connection with tumour dissemination and recurrence in patients with colon cancer.

METHODS:

Disease stage II-IV colon cancer patients (n = 121) were selected. KRAS, BRAF, and PIK3CA mutation status was assessed by pyrosequencing and MSI was determined by analysis of mononucleotide repeat markers. Genome-wide average DNA copy number and allelic imbalance was evaluated by SNP array analysis.

RESULTS:

Patients with mutated KRAS were more likely to experience disease dissemination (OR 2.75; 95% CI 1.28-6.04), whereas the opposite was observed for patients with BRAF mutation (OR 0.34; 95% 0.14-0.81) or MSI (OR 0.24; 95% 0.09-0.64). Also in the subset of patients with stage II-III disease, both MSI (OR 0.29; 95% 0.10-0.86) and BRAF mutation (OR 0.32; 95% 0.16-0.91) were related to lower risk of distant recurrence. However, average DNA copy number and PIK3CA mutations were not associated with disease dissemination.

CONCLUSIONS:

The present study revealed that tumour dissemination is less likely to occur in colon cancer patients with MSI and BRAF mutation, whereas the presence of a KRAS mutation increases the likelihood of disseminated disease.

• Authors: Helgi Birgisson, Karolina Edlund, Ulrik Wallin, Lars Påhlman, Hanna Göransson Kultima, Markus Mayrhofer, Patrick Micke, Anders Isaksson, Johan Botling, Bengt Glimelius, Magnus Sundström
• Journal: BMC cancer (BMC Cancer) Vol. 15 Pg. 125 (Mar 14 2015) ISSN: 1471-2407 [Electronic] England
• PMID: 25884297 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• KRAS protein, human
• Proto-Oncogene Proteins
• BRAF protein, human
• Proto-Oncogene Proteins B-raf
• Proto-Oncogene Proteins p21(ras)
• ras Proteins

Topics

• Aged
• Colonic Neoplasms (diagnosis, genetics)
• Female
• Follow-Up Studies
• Humans
• Male
• Microsatellite Instability
• Mutation (genetics)
• Predictive Value of Tests
• Proto-Oncogene Proteins (genetics)
• Proto-Oncogene Proteins B-raf (genetics)
• Proto-Oncogene Proteins p21(ras)
• ras Proteins (genetics)