Letter

Are triple-negative tumours and basal-like breast cancer synonymous?

Emad A Rakha¹ , David SP Tan² , William D Foulkes³ , Ian O Ellis¹ , Andrew Tutt⁴ , Torsten O Nielsen⁵ and Jorge S Reis-Filho²

¹  Department of Histopathology, Nottingham City Hospital NHS Trust, University of Nottingham, Hucknall Road, Nottingham NG5 1PB, UK

²  The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research, Fulham Road, London, SW3 6JB, UK

³  Program in Cancer Genetics, McGill University, 546 Pine Ave W, Montreal, Quebec H2W 156, Canada

⁴  Breakthrough Breast Cancer Unit at Kings College London, Guy's Hospital, St Thomas' Street, London, SE1 9RT, UK

⁵  British Columbia Cancer Agency, Vancouver Coastal Health Research Institute, and Department of Pathology, University of British Columbia, 855 W. 12th Ave, Vancouver, BC, V5Z 1M9, Canada

author email corresponding author email

Breast Cancer Research 2007, 9:404doi:10.1186/bcr1827

Published:	30 November 2007

See related research article by Kreike et al., http://breast-cancer-research.com/content/9/5/R65 and related letter by Kreike et al., http://breast-cancer-research.com/content/96/6/405

First paragraph (this article has no abstract)

Kreike and colleagues [1] examined the gene expression and pathological characteristics of a retrospectively accrued cohort of 97 triple-negative phenotype (TNP) (oestrogen receptor [ER]-negative, progesterone receptor-negative, and HER2-negative) invasive breast cancers. TNP tumours were profiled with oligonucleotide microarrays and compared with a control group of 102 non-TNP tumours, which were obtained from an unrelated project. The authors then investigated whether the TNP would accurately identify basal-like cancers, by assessing the correlation coefficient between the gene expression profiles of each TNP cancer and the centroids of the molecular subgroups as defined by Hu and colleagues [2]. As expected, the majority (91%) of TNP tumours were classified as 'basal-like' tumours. However, 9% of tumours either showed a normal-like phenotype or were unclassifiable [1]. The authors presented a hierarchical clustering analysis of both TNP and control cases, based on a partial 'intrinsic gene list' and a different reference RNA when compared with those reported by Hu and colleagues [2], and observed that all of the TNP group and 18.6% of the control non-TNP group clustered together [1]. Based on the above results, the authors drew the provocative conclusions that 'basal-like tumours can be reliably defined by triple-negative immunohistochemistry' and that 'triple-negative tumours are synonymous with basal-like tumours'.