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Disease Markers
Volume 22, Issue 5-6, Pages 343-349

Genome Wide Screening of CAG Trinucleotide Repeat Lengths in Breast Cancer

Hamdi Jarjanazi,1,2 Hong Li,1 Irene L. Andrulis,1,2,3 and Hilmi Ozcelik1,2

1F. Litwin Centre for Cancer Genetics, Samuel Lunenfeld Research Institute and Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ont., Canada
2Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ont., Canada
3Molecular and Medical Genetics, University of Toronto, Toronto, Ont., Canada

Received 18 January 2007; Accepted 18 January 2007

Copyright © 2006 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Trinucleotide repeat sequences are widely present in the human genome. The expansion of CAG repeats have been studied very extensively, and shown to be the causative mechanism of more than 40 neuromuscular and neurodegenerative diseases. In the present study, we performed a genome wide screening of CAG repeat expansions in non-neoplastic tissues of 212 breast cancer cases and 196 healthy population controls using the Repeat Expansion Detection (RED) method. Distribution of CAG repeat lengths in cases was not significantly different from controls. However, dramatically expanded CAG repeats were detected in 2.4% (n = 5) of breast cancer cases where no repeats of similar size were detected in any of the healthy population controls. Although this trend shows only borderline significance (p = 0.06), this finding suggests a potential involvement of CAG repeat expansion in breast cancer susceptibility. These repeats may potentially affect the function of cancer predisposition genes, with a similar mechanism as in neurodegenerative and neuromuscular disorders.