Albergaria et al. BMC Cancer 2011, 11:299 http://www.biomedcentral.com/1471-2407/11/299 R E S E A R C H A R T I C L E Open Access Nottingham Prognostic Index in Triple-Negative Breast Cancer: a reliable prognostic tool? André Albergaria1, Sara Ricardo1,2, Fernanda Milanezi1, Vítor Carneiro3, Isabel Amendoeira4, Daniella Vieira5, Jorge Cameselle-Teijeiro6 and Fernando Schmitt1,4* Abstract Background: A breast cancer prognostic tool should ideally be applicable to all types of invasive breast lesions. A number of studies have shown histopathological grade to be an independent prognostic factor in breast cancer, adding prognostic power to nodal stage and tumour size. The Nottingham Prognostic Index has been shown to accurately predict patient outcome in stratified groups with a follow-up period of 15 years after primary diagnosis of breast cancer. Clinically, breast tumours that lack the expression of Oestrogen Receptor, Progesterone Receptor and Human Epidermal growth factor Receptor 2 (HER2) are identified as presenting a “triple-negative” phenotype or as triple-negative breast cancers. These poor outcome tumours represent an easily recognisable prognostic group of breast cancer with aggressive behaviour that currently lack the benefit of available systemic therapy. There are conflicting results on the prevalence of lymph node metastasis at the time of diagnosis in triple-negative breast cancer patients but it is currently accepted that triple-negative breast cancer does not metastasize to axillary nodes and bones as frequently as the non-triple-negative carcinomas, favouring instead, a preferentially haematogenous spread. Hypothetically, this particular tumour dissemination pattern would impair the reliability of using Nottingham Prognostic Index as a tool for triple-negative breast cancer prognostication. Methods: The present study tested the effectiveness of the Nottingham Prognostic Index in stratifying breast cancer patients of different subtypes with special emphasis in a triple-negative breast cancer patient subset versus non- triple-negative breast cancer. Results: We demonstrated that besides the fact that TNBC disseminate to axillary lymph nodes as frequently as luminal or HER2 tumours, we also showed that TNBC are larger in size compared with other subtypes and almost all grade 3. Additionally, survival curves demonstrated that these prognostic factors are equally important to stratify different survival outcomes in non-TNBC as in TNBC. We also showed that the NPI retains the ability to stratify and predict survival of TNBC patients. Conclusion: The importance of this study relies on the need of prognostication improvements on TNBC, showing, at a clinical standpoint, that Nottingham Prognostic Index is as a truthful prognostic tool in TNBC. Background Breast cancer comprises a complex and heterogeneous group of diseases at clinical, morphological and molecu- lar levels [1-3]. It is clear that breast tumours of the same histological type show remarkably different clinical behaviour, which is probably a reflex of their distinct pattern of molecular aberrations [1,4]. Microarray tech- nology has changed the way we understand breast * Correspondence: fschmitt@ipatimup.pt 1Institute of Molecular Pathology and Immunology of Porto University (IPATIMUP), Porto, Portugal Full list of author information is available at the end of the article cancer classification by looking towards a molecular- based approach instead the traditional morphology and histopathological-based system [5,6]. Pioneered by the Stanford group [6-9] and lately explored by several other groups, a new taxonomy for breast cancer based on expression profile has claimed that the morphologi- cal heterogeneity of breast cancer can be recapitulated and systematically classified at the transcriptomic level and into clinically meaningful groups [10-12]. Such stu- dies have shown that the molecular profile of breast cancer present a systematic variation which allowed its differential identification into two distinct branches [11], © 2011 Albergaria et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.