Research article

BCoR-L1 variation and breast cancer

Felicity Lose^1,2, Jeremy Arnold¹, David B Young¹, Carolyn J Brown³, Graham J Mann⁴, Gulietta M Pupo⁴, The Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer, Kum K Khanna¹, Georgia Chenevix-Trench¹ and Amanda B Spurdle^1*

• * Corresponding author: Amanda B Spurdle Amanda.Spurdle@qimr.edu.au

Author Affiliations

¹ Cancer and Cell Biology Division, Queensland Institute of Medical Research, 300 Herston Road, Brisbane, Queensland, Australia, 4006

² School of Medicine, Central Clinical Division, University of Queensland, Royal Brisbane Hospital, Corner Butterfield Street and Bowen Bridge Road, Brisbane, Queensland, Australia, 4029

³ Department of Medical Genetics, Molecular Epigenetics Group, University of British Columbia, 2329 West Mall, Vancouver, BC, Canada, V6T 1Z4

⁴ Westmead Institute for Cancer Research, University of Sydney at Westmead Millennium Institute, Westmead Hospital, Darcy Road, Westmead, New South Wales, Australia, 2145

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Breast Cancer Research 2007, 9:R54 doi:10.1186/bcr1759

Published: 16 August 2007

Abstract

Introduction

BRCA1 is involved in numerous essential processes in the cell, and the effects of BRCA1 dysfunction in breast cancer carcinogenesis are well described. Many of the breast cancer susceptibility genes such as BRCA2, p53, ATM, CHEK2, and BRIP1 encode proteins that interact with BRCA1. BCL6 corepressor-like 1 (BCoR-L1) is a newly described BRCA1-interacting protein that displays high homology to several proteins known to be involved in the fundamental processes of DNA damage repair and transcription regulation. BCoR-L1 has been shown to play a role in transcription corepression, and expression of the X-linked BCoR-L1 gene has been reported to be dysregulated in breast cancer subjects. BCoR-L1 is located on the X chromosome and is subject to X inactivation.

Methods

We performed mutation analysis of 38 BRCA1/2 mutation-negative breast cancer families with male breast cancer, prostate cancer, and/or haplotype sharing around BCoR-L1 to determine whether there is a role for BCoR-L1 as a high-risk breast cancer predisposition gene. In addition, we conducted quantitative real-time PCR (qRT-PCR) on lymphoblastoid cell lines (LCLs) from the index cases from these families and a number of cancer cell lines to assess the role of BCoR-L1 dysregulation in cancer and cancer families.

Results

Very little variation was detected in the coding region, and qRT-PCR analysis revealed that BCoR-L1 expression is highly variable in cancer-free subjects, high-risk breast cancer patients, and cancer cell lines. We also report the investigation of a new expression control, DIDO1 (death inducer-obliterator 1), that is superior to GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and UBC (ubiquitin C) for analysis of expression in LCLs.

Conclusion

Our results suggest that BCoR-L1 expression does not play a large role in predisposition to familial breast cancer.