BMJ Open 4:e004652 doi:10.1136/bmjopen-2013-004652
  • Oncology
    • Research

KRAS, NRAS and BRAF mutations in Greek and Romanian patients with colorectal cancer: a cohort study

  1. George Nasioulas2
  1. 1University of Medicine and Pharmacy of Timisoara, Timisoara, Romania
  2. 2Department of Molecular Biology, GENEKOR, Athens, Greece
  3. 3Institute of Oncology, Bucharest, Romania
  4. 4Institute of Oncology Ion Chiricuta, Cluj-Napoca, Romania
  5. 5Centrul de Oncologie Medicala, Iasi, Romania
  6. 6Department of Medical Oncology, Fundeni Clinical Institute Bucharest, Bucharest, Romania
  7. 7Department of Medical Oncology, University General Hospital of Alexandroupolis, Thrace, Greece
  8. 8Second Department of Medical Oncology, “Agii Anargiri” Cancer Hospital, Athens, Greece
  9. 9First Department of Medical Oncology, ‘METAXA’ Anticancer Hospital of Athens, Athens, Greece
  10. 10Department of Medical Oncology, Mitera Hospital, Athens, Greece
  11. 11Department of Medical Oncology, Interbalkan Medical Center, Thessaloniki, Greece
  12. 12Department of Medical Oncology, University of Ioannina School of Medicine, Ioannina, Greece
  13. 13Clinical Oncology Laboratory, Division of Oncology, Department of Medicine, University of Patras, Patras Medical School, Rio, Greece
  1. Correspondence to Dr George Nasioulas; gnasioulas{at}
  • Received 13 December 2013
  • Revised 9 April 2014
  • Accepted 2 May 2014
  • Published 23 May 2014


Objectives Treatment decision-making in colorectal cancer is often guided by tumour tissue molecular analysis. The aim of this study was the development and validation of a high-resolution melting (HRM) method for the detection of KRAS, NRAS and BRAF mutations in Greek and Romanian patients with colorectal cancer and determination of the frequency of these mutations in the respective populations.

Setting Diagnostic molecular laboratory located in Athens, Greece.

Participants 2425 patients with colorectal cancer participated in the study.

Primary and secondary outcome measures 2071 patients with colorectal cancer (1699 of Greek and 372 of Romanian origin) were analysed for KRAS exon 2 mutations. In addition, 354 tumours from consecutive patients (196 Greek and 161 Romanian) were subjected to full KRAS (exons 2, 3 and 4), NRAS (exons 2, 3 and 4) and BRAF (exon 15) analysis. KRAS, NRAS and BRAF mutation detection was performed by a newly designed HRM analysis protocol, followed by Sanger sequencing.

Results KRAS exon 2 mutations (codons 12/13) were detected in 702 of the 1699 Greek patients with colorectal carcinoma analysed (41.3%) and in 39.2% (146/372) of the Romanian patients. Among the 354 patients who were subjected to full KRAS, NRAS and BRAF analysis, 40.96% had KRAS exon 2 mutations (codons 12/13). Among the KRAS exon 2 wild-type patients 15.31% harboured additional RAS mutations and 12.44% BRAF mutations. The newly designed HRM method used showed a higher sensitivity compared with the sequencing method.

Conclusions The HRM method developed was shown to be a reliable method for KRAS, NRAS and BRAF mutation detection. Furthermore, no difference in the mutation frequency of KRAS, NRAS and BRAF was observed between Greek and Romanian patients with colorectal cancer.

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