Research

Genome-wide expression patterns of invasion front, inner tumor mass and surrounding normal epithelium of colorectal tumors

Eike Staub^1,2 , Joern Groene⁴ , Maya Heinze⁴ , Detlev Mennerich⁵ , Stefan Roepcke^1,11 , Irina Klaman⁶ , Bernd Hinzmann⁶ , Esmeralda Castanos-Velez⁷ , Christian Pilarsky⁸ , Benno Mann⁹ , Thomas Brümmendorf^3,10 , Birgit Weber^3,12 , Heinz-Johannes Buhr⁴ and André Rosenthal⁶

¹  Max Planck Institute for Molecular Genetics, Department of Computational Molecular Biology, Berlin, Germany

²  Merck Serono, Bio- & Chemoinformatics, Darmstadt, Germany

³  metaGen Pharmaceuticals i.L., Berlin, Germany

⁴  Charité – Campus Benjamin Franklin, Department of General, Vascular and Thoracic Surgery, Berlin, Germany

⁵  Boehringer Ingelheim Pharma GmbH & Co KG, Biberach, Germany

⁶  Signature Diagnostics, Potsdam, Germany

⁷  Epigenomics, Berlin, Germany

⁸  University Hospital Carl Gustav Carus Dresden, Department of Visceral, Thoracic, and Vascular Surgery, Germany

⁹  Augusta-Kranken-Anstalt GmbH, Department of Surgery, Bochum, Germany

¹⁰  Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland

¹¹  Nycomed, Konstanz, Germany

¹²  ratiopharm, Ulm, Germany

author email corresponding author email

Molecular Cancer 2007, 6:79doi:10.1186/1476-4598-6-79

Published:	14 December 2007

Abstract

Colorectal tumors have characteristic genome-wide expression patterns that allow their distinction from normal colon epithelia and facilitate clinical prognosis. The expression heterogeneity within a primary colorectal tumor has not been studied on a genome scale yet. Here we investigated three compartments of colorectal tumors, the invasion front, the inner tumor mass, and surrounding normal epithelial tissue by microdissection and microarray-based expression profiling. In both tumor compartments many genes were differentially expressed when compared to normal epithelium. The sets of significantly deregulated genes in both compartments overlapped to a large extent and revealed various interesting known and novel pathways that could have contributed to tumorigenesis. Cells from the invasion front and inner tumor mass, however, did not show significant differences in their expression profile, neither on the single gene level nor on the pathway level. Instead, gene expression differences between individuals are more pronounced as all patient-matched tumor samples clustered in close proximity to each other. With respect to invasion front and inner tumor mass we conclude that the specific tumor cell micro-environment does not have a strong influence on expression patterns: largely similar genome-wide expression programs operate in the invasion front and interior compartment of a colorectal tumor.