Novel KRAS gene mutations in sporadic colorectal cancer

Walid M. Naser, Mohamed A. Shawarby, Dalal M. Al-Tamimi, Arun Seth, Abdulaziz Al-Quorain, Areej M Al Nemer, Omar Al Bagha

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Introduction: In this article, we report 7 novel KRAS gene mutations discovered while retrospectively studying the prevalence and pattern of KRAS mutations in cancerous tissue obtained from 56 Saudi sporadic colorectal cancer patients from the Eastern Province.

Methods: Genomic DNA was extracted from formalin-fixed, paraffin-embedded cancerous and noncancerous colorectal tissues. Successful and specific PCR products were then bi-directionally sequenced to detect exon 4 mutations while Mutector II Detection Kits were used for identifying mutations in codons 12, 13 and 61. The functional impact of the novel mutations was assessed using bioinformatics tools and molecular modeling.

Results: KRAS gene mutations were detected in the cancer tissue of 24 cases (42.85%). Of these, 11 had exon 4 mutations (19.64%). They harbored 8 different mutations all of which except two altered the KRAS protein amino acid sequence and all except one were novel as revealed by COSMIC database. The detected novel mutations were found to be somatic. One mutation is predicted to be benign. The remaining mutations are predicted to cause substantial changes in the protein structure. Of these, the Q150X nonsense mutation is the second truncating mutation to be reported in colorectal cancer in the literature.

Conclusions: Our discovery of novel exon 4 KRAS mutations that are, so far, unique to Saudi colorectal cancer patients may be attributed to environmental factors and/or racial/ethnic variations due to genetic differences. Alternatively, it may be related to paucity of clinical studies on mutations other than those in codons 12, 13, 61 and 146. Further KRAS testing on a large number of patients of various ethnicities, particularly beyond the most common hotspot alleles in exons 2 and 3 is needed to assess the prevalence and explore the exact prognostic and predictive significance of the discovered novel mutations as well as their possible role in colorectal carcinogenesis.

Original languageEnglish
Article numbere113350
JournalPLoS One
Volume9
Issue number11
DOIs
Publication statusPublished - 20 Nov 2014
Externally publishedYes

Fingerprint

colorectal neoplasms
Colorectal Neoplasms
Exons
Genes
mutation
Mutation
Tissue
genes
Molecular modeling
Bioinformatics
exons
Paraffin
Formaldehyde
Proteins
Amino Acids
DNA
Testing
codons
Codon
nonsense mutation

ASJC Scopus subject areas

  • Medicine(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

Naser, W. M., Shawarby, M. A., Al-Tamimi, D. M., Seth, A., Al-Quorain, A., Nemer, A. M. A., & Al Bagha, O. (2014). Novel KRAS gene mutations in sporadic colorectal cancer. PLoS One, 9(11), [e113350]. https://doi.org/10.1371/journal.pone.0113350

Novel KRAS gene mutations in sporadic colorectal cancer. / Naser, Walid M.; Shawarby, Mohamed A.; Al-Tamimi, Dalal M.; Seth, Arun; Al-Quorain, Abdulaziz; Nemer, Areej M Al; Al Bagha, Omar.

In: PLoS One, Vol. 9, No. 11, e113350, 20.11.2014.

Research output: Contribution to journalArticle

Naser, WM, Shawarby, MA, Al-Tamimi, DM, Seth, A, Al-Quorain, A, Nemer, AMA & Al Bagha, O 2014, 'Novel KRAS gene mutations in sporadic colorectal cancer', PLoS One, vol. 9, no. 11, e113350. https://doi.org/10.1371/journal.pone.0113350
Naser WM, Shawarby MA, Al-Tamimi DM, Seth A, Al-Quorain A, Nemer AMA et al. Novel KRAS gene mutations in sporadic colorectal cancer. PLoS One. 2014 Nov 20;9(11). e113350. https://doi.org/10.1371/journal.pone.0113350
Naser, Walid M. ; Shawarby, Mohamed A. ; Al-Tamimi, Dalal M. ; Seth, Arun ; Al-Quorain, Abdulaziz ; Nemer, Areej M Al ; Al Bagha, Omar. / Novel KRAS gene mutations in sporadic colorectal cancer. In: PLoS One. 2014 ; Vol. 9, No. 11.
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