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IRS2 is a candidate driver oncogene on 13q34 in colorectal cancer
Author(s) -
Day Elizabeth,
Poulogiannis George,
McCaughan Frank,
Mulholland Shani,
Arends Mark J.,
Ibrahim Ashraf E. K.,
Dear Paul H.
Publication year - 2013
Publication title -
international journal of experimental pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.671
H-Index - 72
eISSN - 1365-2613
pISSN - 0959-9673
DOI - 10.1111/iep.12021
Subject(s) - oncogene , gene duplication , biology , colorectal cancer , cancer , cancer research , carcinogenesis , deleted in colorectal cancer , gene , genetics , cell cycle
Summary Copy number alterations are frequently found in colorectal cancer ( CRC ), and recurrent gains or losses are likely to correspond to regions harbouring genes that promote or impede carcinogenesis respectively. Gain of chromosome 13q is common in CRC but, because the region of gain is frequently large, identification of the driver gene(s) has hitherto proved difficult. We used array comparative genomic hybridization to analyse 124 primary CRC s, demonstrating that 13q34 is a region of gain in 35% of CRC s, with focal gains in 4% and amplification in a further 1.6% of cases. To reduce the number of potential driver genes to consider, it was necessary to refine the boundaries of the narrowest copy number changes seen in this series and hence define the minimal copy region ( MCR ). This was performed using molecular copy‐number counting, identifying IRS2 as the only complete gene, and therefore the likely driver oncogene, within the refined MCR . Analysis of available colorectal neoplasia data sets confirmed IRS2 gene gain as a common event. Furthermore, IRS 2 protein and m RNA expression in colorectal neoplasia was assessed and was positively correlated with progression from normal through adenoma to carcinoma. In functional in vitro experiments, we demonstrate that deregulated expression of IRS 2 activates the oncogenic PI 3 kinase pathway and increases cell adhesion, both characteristics of invasive CRC cells. Together, these data identify IRS2 as a likely driver oncogene in the prevalent 13q34 region of gain/amplification and suggest that IRS 2 over‐expression may provide an additional mechanism of PI 3 kinase pathway activation in CRC .