KRAS mutation detection in Tunisian sporadic coloractal cancer patients with direct sequencing, high resolution melting and denaturating high performance liquid chromatography

Article type: Research Article

Authors: Karim, Bougatef^{a; *} | Florence, Coulet^b | Kamel, Rouissi^a | Nadia, Kourda^c | Ines, Omrane^a | Raja, Marrakchi^a | Sarra, Ben Jileni^c | Florent, Soubrier^{b; 1} | Amel, Ben Ammar-Elgaaied^{a; 1}

Affiliations: [a] Laboratoire de Génétique, Immunologie et Pathologies Humaines, Faculté des Sciences de Tunis, Université de Tunis El Manar, Tunisia | [b] Laboratoire d'Oncogénétique et d'Angiogénétique Moléculaire, Groupe Hospitalier Pitié-Salpêtrière, Paris, France | [c] Laboratoire d'anatomo-pathologies, Hôpital Charles Nicolle de Tunis, Tunis, Tunisia

Correspondence: [*] Corresponding author: Laboratoire de Génétique, Immunologie et Pathologies Humaines, Faculté des sciences de Tunis, Université de Tunis El Manar, Tunisia. Tel.: +216 98 48 98 31; E-mail: [email protected].

Note: [1] The authors have collaborated on the same level.

Abstract: The Kirsten Rat Sarcoma (KRAS) oncogene has been introduced recently as a genetic biomarker for metastatic sporadic colorectal cancer prior to anti-EGFR treatment. Identifying patients with KRAS mutations that not respond to EGFR targeted therapies require sensitive, rapid and efficacious routine technique. We have attempted to evaluate the efficiency of three conventional methods: direct sequencing, HRM and DHPLC, to detect mutations in codon 12 and 13 of the KRAS exon2 gene. For this first Tunisian study on KRAS, we detected 45.83% of altered KRAS gene among 48 formalin-fixed paraffin-embedded sporadic colorectal adenocarcinoma patients. The use of HRM-sequencing allowed as enlarging the detected KRAS exon 2 mutations (22/48) in comparison with direct sequencing (17/48). DHPLC was used to confirm results when consensus was not observed between HRM and direct sequencing. This study brings an interesting data concerning an inter-method validation between sequencing and HRM in the investigation of sporadic colorectal cancer biomarker. It also shows that KRAS mutations occur at similar frequencies in Tunisian patients as in other populations; and suggests that the same genes are at play in sporadic CRC cancer, despite ethnic, geographical and environmental differences between countries.

Keywords: Sporadic colorectal cancer, biomarker, KRAS, EGFR, HRM, DHPLC, direct sequencing

DOI: 10.3233/CBM-2011-0222

Journal: Cancer Biomarkers, vol. 8, no. 6, pp. 331-340, 2011