Mutation status of full RAS and BRAF in 169 Moroccan patients with colorectal cancer.

Authors

null

Sara El Zaitouni

Laboratory of Biology of Human Pathologies, Genomic Center of Human Pathologies, Department of Biology, Faculty of Sciences, Mohammed V University in Rabat, Rabat, Morocco;

Sara El Zaitouni , Abdelilah Laraqui , Meriem Ghaouti , Asmae Benzekri , Fouad Kettani , Hicham El Annaz , Rachid Abi , Mohamed Rida Tagajdid , Safae El Kochri , Idriss Amine Lahlou , Rabii Ameziane El Hassani , Khalid Ennibi

Organizations

Laboratory of Biology of Human Pathologies, Genomic Center of Human Pathologies, Department of Biology, Faculty of Sciences, Mohammed V University in Rabat, Rabat, Morocco; , Sequencing Unit, Laboratory of Virology, Center of Virology, Infectious and Tropical Diseases, Mohammed V Military Teaching Hospital, Faculty of Medicine and Pharmacy, Mohammed V University in Rabat, Rabat, Morocco; , Department of Pathology, Nations-Unites Pathology Center, Rabat, Morocco;

Research Funding

No funding received
None.

Background: Morocco has the highest cancer mortality rate in MENA Countries. Colorectal cancer (CRC) is classified as the first digestive cancer and remains a burden in Morocco. According to the data on GLOBOCAN 2020, there were 4324 new CRC patients and 2374 deaths, accounting for 7.3% and 2.8% of all cancers, respectively. Our study aimed to investigate the frequency of the full RAS (KRAS, NRAS) and BRAF genes in CRC patients from Morocco and their possible associations with clinico-pathological features. Methods: Archived FFPE of 169 CRC patients were screened for KRAS, NRAS and BRAF mutations by Idylla technology. Results: Full RAS mutations were identified in 46.1% (42% in KRAS, 4.1% in NRAS). In KRAS gene, exon 2 mutations accounted for 84.5% (69% in codon 12, 15.5 % in codon 13). Within codon 12, KRAS G12D and G12C were more frequently detected (29.5% and 16.9%, respectively). Detection of KRAS mutations, and particularly G12D and G12C subtypes, are of large significance for CRC patients, have possible therapeutic implications. Within codon 13, the most frequently observed mutation was G13D (15.5 %). Outside exon 2, the mutation rate was 35.1% (8.4% in exon 3 and 26.7% in exon 4). Concurrent KRAS mutations were identified in 8 cases, which suggests that multiple mutations can occur in the same or different codons. In NRAS gene, the mutation rates of exon 2 and 3 were 71.4% and 57.1% respectively. G13V and Q61K were the most common mutations, accounting for 28.6 % of each. Concurrent KRAS mutations were identified in 2 cases. Of the 169 samples, mutations in the BRAF gene at V600E were detected in 3.5%. Combined mutational analysis of KRAS, NRAS and BRAF was able to identify 49.6% of patients with CRC as likely non-responders to anti-EGFR therapy. There was an association between KRAS mutations and age, which were higher in the age group>50 years old (p=0.022). Tumors in the left colon (36.61%) are more likely to harbor mutations in KRAS than the rectum (19.7%) in both sexes. The adenocarcinoma well-differentiated was the most frequent for patients with KRAS mutations (54.9%). No significant clinicopathologic correlations with NRAS and BRAF mutations were identified. Conclusions: Beside established anti-CRC treatment, better understanding of the causality of CRC can be established by combining epidemiology and genetic/epigenetic on CRC etiology in Morocco. This approach may be able to significantly reduce the burden of disease in the country. Moreover, the Moroccan government should develop policy on CRC prevention and public health programs which may serve as a feasible setting to increase public awareness on lifestyle risk factors.

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Abstract Details

Meeting

2023 ASCO Gastrointestinal Cancers Symposium

Session Type

Poster Session

Session Title

Poster Session C: Cancers of the Colon, Rectum, and Anus

Track

Colorectal Cancer,Anal Cancer

Sub Track

Tumor Biology, Biomarkers, and Pathology

Citation

J Clin Oncol 41, 2023 (suppl 4; abstr 216)

DOI

10.1200/JCO.2023.41.4_suppl.216

Abstract #

216

Poster Bd #

L18

Abstract Disclosures

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