Open Access Research article

Allelotyping identification of genomic alterations in rectal chromosomally unstable tumors without preoperative treatment

Benoît Romain12*, Agnès Neuville23, Nicolas Meyer4, Cécile Brigand1, Serge Rohr1, Anne Schneider5, Marie-Pierre Gaub25 and Dominique Guenot2

Author Affiliations

1 Service de Chirurgie Générale et Digestive, Hôpitaux Universitaires de Strasbourg, Hôpital de Hautepierre, Avenue Molière, 67098 Strasbourg Cedex, France

2 Université de Strasbourg (UdS), EA 4438 Physiopathologie et Médecine Translationnelle, 3 Avenue Molière, 67200 Strasbourg, France

3 Laboratoire d'Anatomie Pathologique, Hôpitaux Universitaires de Strasbourg, Hôpital de Hautepierre, Avenue Molière, 67098 Strasbourg Cedex, France

4 Département de Santé Publique, CHRU, 67091 Strasbourg Cedex, France

5 Laboratoire de Biochimie et Biologie Moléculaire, Hôpitaux Universitaires de Strasbourg, Hôpital de Hautepierre, Avenue Molière, 67098 Strasbourg Cedex, France

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BMC Cancer 2010, 10:561  doi:10.1186/1471-2407-10-561

Published: 18 October 2010

Abstract

Background

Numerous studies reported genomic alterations in colorectal human tumors but few focused on rectal tumors with the specification of preoperative-treated or untreated tumors. The goals of this study were to list chromosome allelic imbalances and correlate their frequency with tumor progression and to identify potential molecular markers of progression in rectal chromosomally unstable tumors without preoperative treatment.

Methods

Genomic alterations of 57 rectal tumors assessed by allelotyping targeting 33 chromosomal loci, were clusterised and compared to those of 151 left colon tumors.

Results

Clustering separated the rectal tumors without preoperative treatment into three subtypes according to the allelic imbalance frequency and genomic alteration associations. The tumors without preoperative treatment displayed a significantly higher allelic imbalance frequency (54%) than the tumors with preoperative treatment (33%), suggesting that treatment could target highly altered tumor clones. Interestingly, the survival analysis identified three potential prognostic molecular survival markers, D1S197, D5S430, and D14S65, for tumors without preoperative treatment.

Conclusion

Based on the genomic status of 33 chromosomal loci, we observed that rectal tumors without preoperative treatment segregate according to the global allelic imbalance frequency but without correlation to the tumor progression. Moreover, the detailed associations of alterations in rectal tumors are different from those described in colon tumors suggesting that rectal and left tumors should be considered as separate entities. Finally, potential prognostic genomic molecular markers for survival are proposed which status could specify the clinical course of the tumors.