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Clinical Significance of Somatic Mutations in RAS/RAF/MAPK Signaling Pathway in Moroccan and North African Colorectal Cancer Patients

  • Benmokhtar, Soukaina
  • Laraqui, Abdelilah
  • El Boukhrissi, Fatima
  • Hilali, Farida
  • Bajjou, Tahar
  • Jafari, Meryem
  • Elzaitouni, Sara
  • Baba, Walid
  • El Mchichi, Bouchra
  • Elannaz, Hicham
  • Lahlou, Idriss Amine
  • Chahdi, Hafsa
  • Oukabli, Mohamed
  • Mahfoud, Tarik
  • Tanz, Rachid
  • Ichou, Mohamed
  • Ennibi, Khaled
  • Dakka, Nadia
  • Sekhsokh, Yassine
Published Article
Asian Pacific Journal of Cancer Prevention : APJCP
West Asia Organization for Cancer Prevention
Publication Date
Nov 01, 2022
DOI: 10.31557/APJCP.2022.23.11.3725
PMID: 36444585
PMCID: PMC9930961
PubMed Central
  • Research Article


Background: Mutations in RAS ( KRAS, NRAS ) and BRAF genes are the main biomarker predicting response to anti-EGFR monoclonal antibodies in targeted therapy in colorectal cancer (CRC). Objective: Our study aims to evaluate the frequencies of KRAS, NRAS and BRAF mutations and their possible associations with clinico-pathological features in CRC patients from Morocco. Methods: DNA was extracted from 80 FFPE samples using the QIAamp DNA FFPE-kit. RAS and BRAF mutations were assessed by pyrosequencing assays using Qiagen, KRAS Pyro®kit 24.V1, Ras-Extension Pyro®kit 24.V1 and BRAF Pyro®Kit 24.V1, respectively, and carried out in the PyroMark-Q24. Results: RAS mutations were identified in 57.5% (56.2% in KRAS, 8.8% in NRAS). In KRAS gene, exon 2 mutations accounted for 93.3% (68.9% in codon 12, 24.4% in codon 13). Within codon 12, G12D was the most prevalent mutation (37.7%), followed by G12C (13.4%), G12S (8.9%) and G12V (6.6%). Within codon 13, the most frequently observed mutation was G13D (22.3%). The mutation rates of exon 3 and 4 were 15.6% and 13.3%, respectively. In exon 3 codon 61, 2.3% patients were detected with two concurrent mutations (Q61R, Q61H), and 4.4% with three concurrent mutations (Q61R, Q61H, Q61L). In NRAS gene, the mutation rates of exon 2, 3 and 4 were 57.1%, 28.6%, and 14.3%, respectively. G13A and Q61H were the most common mutations, accounting for 42.9% and 28.5%, respectively. There were 13% patients with concurrent KRAS/NRAS mutation and 4.3% wt KRAS with NRAS mutations. No mutations were identified in BRAF gene. In both sexes, KRAS codon 12 mutations were associated with higher stage III/IV tumors. Moreover, Patients whose tumor is in the proximal colon (56.3%) are more likely to harbor KRAS mutations than those tumor located in rectum (25%). Conclusion: RAS mutations could be useful in future target anti-EGFR therapy and molecular CRC screening strategy in Morocco.

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