Abstract
Background: A recent study showed a higher frequency of GA deletion at rs67491583 in African American colorectal cancer (CRC) patients compared to controls, suggesting a likely contribution of this allele to racial disparity in CRC risk predisposition. We conducted apilot study in an indigenous African population to evaluate this potential CRC risk variant.
Methods: We collected epidemiological data and biological specimen from consenting consecutive CRC cases and controls presenting at the Oncology Clinic of University College Hospital, Ibadan from 2001 to 2007. We examined germline DNA for delGA by PCR-amplification of two overlapping fragments using standard primers. The products were directly sequenced using Applied Biosystems BigDye v3.1 sequencing chemistry and AB13730 automatic DNA sequencer.
Results: There were 45 cases and 45 controls of which genotyping was successful in 39 cases and 38 controls. There were 5 heterozygous and 2 homozygous GA deletions with frequency of 11.54% (9/78) among cases whereas there were 8 heterozygous and 1homozygous GA deletions among controls with frequency of 13.15% (10/76). (p= 0.79, OR 0.88, 95% CI 0.34-2.28)
Conclusion: This study suggests that there is no association between the delGA (rs67491583) variant and CRC risk in thisindigenous African population. However our sample size was small and the participants were not ethnically homogenous. Further studies are required to evaluate this marker in African CRC.
Keywords: rs67491583, colorectal cancer risk, Nigeria
Abstrait
Objectif: Une étude récente a montré une fréquence plus élevée de la suppression de GA à rs67491583 chez les patients atteints du cancer colorectal des afro-américains (CRC) par rapport aux témoins, suggérant une contribution probable de cet allèle à une disparité raciale dans le risque de prédisposition du CCR. Nous avons mémé une enquête pilote auprès d’une population africaine indigène pour évaluer cette variante risque potentiel du CRC.
Méthodes: Nous avons recueilli des données épidémiologiques et des échantillons biologiques des cas de CCR consécutivement consentis et des contrôles présentés à la clinique d’oncologie du centre hospitalier universitaire d’ Ibadan de 2001 à 2007. Nous avons examiné la lignée germinale ADN pour DelGA par amplification PCR de deux fragments chevauchants en utilisant des amorces standard. Les produits ont été directement séquencés à l’aide de l’application BiosystemsBigDye v3.1 séquençage de la chimie et du séquenceur AB13730 d’ADN automatique.
Résultats: Il y avait 45 cas et 45 contrôles dont le génotypage a réussi dans 39 cas et 38 contrôles. Il y avait la suppression GA de 5 hétérozygotes et de 2 homozygotes avec une fréquence de 11,54% (9/78) parmi les cas tandis qu’il y avait la GA de 8 hétérozygotes et d’1 homozygotes chez les témoins avec une fréquence de 13,15% (10/76). (p = 0,79, OR 0,88, IC à 95% 0.34 -2.28)
Conclusion: Cette étude suggère qu’il n’y a pas d’association entre la variante de DelGA (rs67491583) et le risque de CCR parmi cette population indigène africaine. Cependant la taille de notre échantillon était petite et les participants n’étaient pas ethniquement homogènes. D’autres études sont nécessaires pour évaluer cet élément important chez les CRC africains.
Correspondence: Dr. Temkitayo Ogundiran, Department of Surgery, University College Hospital, Ibadan, Nigeria. Email: toogundiran@yahoo.co.uk
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