@article{8902087f08fd490b87edcfcc6fcf3504,
title = "Heterogeneity of luminal breast cancer characterised by immunohistochemical expression of basal markers",
abstract = "Background:Luminal A breast cancer defined as hormone receptor positive and human epidermal growth factor receptor 2 (HER2) negative is known to be heterogeneous. Previous study showed that luminal A tumours with the expression of basal markers ((cytokeratin (CK) 5 or CK5/6) or epidermal growth factor receptor (EGFR)) were associated with poorer prognosis compared with those that stained negative for basal markers. Prompted by this study, we assessed whether tumour characteristics and risk factors differed by basal marker status within luminal A tumours.Methods:We pooled 5040 luminal A cases defined by immunohistochemistry (4490 basal-negative ((CK5 (or CK5/6))- and EGFR-) and 550 basal-positive ((CK5 (or CK5/6+)) or EGFR+)) from eight studies participating in the Breast Cancer Association Consortium. Case-case comparison was performed using unconditional logistic regression.Results:Tumour characteristics and risk factors did not vary significantly by the expression of basal markers, although results suggested that basal-positive luminal tumours tended to be smaller and node negative, and were more common in women with a positive family history and lower body mass index.Conclusions:Most established breast cancer risk factors were similar in basal-positive and basal-negative luminal A tumours. The non-significant but suggestive differences in tumour features and family history warrant further investigations.",
keywords = "CK5/6, EGFR, breast cancer, luminal A tumour, risk factors, tumour characteristics",
author = "Hyuna Sung and Montserrat Garcia-Closas and Jenny Chang-Claude and Blows, {Fiona M.} and Ali, {H. Raza} and Jonine Figueroa and Heli Nevanlinna and Rainer Fagerholm and Paivi Heikkil{\"a} and Carl Blomqvist and Giles, {Graham G.} and Milne, {Roger L.} and Southey, {Melissa C.} and Catriona McLean and Arto Mannermaa and Kosma, {Veli Matti} and Vesa Kataja and Reijo Sironen and Couch, {Fergus J.} and Olson, {Janet E.} and Emily Hallberg and Curtis Olswold and Angela Cox and Cross, {Simon S.} and Peter Kraft and Tamimi, {Rulla M.} and Eliassen, {A. Heather} and Schmidt, {Marjanka K.} and Bolla, {Manjeet K.} and Qin Wang and Douglas Easton and Howat, {William J.} and Penny Coulson and Pharoah, {Paul D.P.} and Sherman, {Mark E.} and Yang, {Xiaohong R.}",
note = "Funding Information: The Helsinki Breast Cancer Study (HEBCS) thanks Kristiina Aittom{\"a}ki, Kirsimari Aaltonen, Taru A Muranen, Karl von Smitten, and Irja Erkkil{\"a} for their kind help with the patient samples and data. The Study of Epidemiology and Risk factors in Cancer Heredity (SEARCH) thanks Elena Provenzano and Marie Mack. The HEBCS was supported by The Helsinki University Central Hospital Research Fund, Academy of Finland (266528), the Finnish Cancer Society, and The Nordic Cancer Union and the Sigrid Juselius Foundation. The Mayo Clinic Breast Cancer Study (MCBCS) was supported by The Breast Cancer Research Foundation, the National Institutes of Health Specialized Program of Research Excellence (SPORE) in Breast Cancer (CA116201), R01 grants (CA128978 and CA176785), and the Grohne Family. The Melbourne Collaborative Cohort Study (MCCS) was supported by The Cancer Council Victoria, VicHealth, NHMRC (209057, 251533, 396414, and 504711), Victorian Cancer Registry (VCR) and the Australian Institute of Health and Welfare (AIHW), including the National Death Index (NDI). The Nurses{\textquoteright} Health Study (NHS) was supported by National Institutes of Health/ National Cancer Institute (UM1 CA186107 and P01 CA 87969). The NHS thanks the following state cancer registries for their help: AL, AZ, AR, CA, CO, CT, DE, FL, GA, ID, IL, IN, IA, KY, LA, ME, MD, MA, MI, NE, NH, NJ, NY, NC, ND, OH, OK, OR, PA, RI, SC, TN, TX, VA, WA, WY. The Polish Breast Cancer Study (PBCS) was supported by Intramural Research Program of US NIH, NCI, Division of Cancer Epidemiology and Genetics (DCEG). The Sheffield Breast Cancer Study (SBCS) was supported by Yorkshire Cancer Research (S295, S299, and S305PA) and Sheffield Experimental Cancer Medicine Centre. The SEARCH was supported by Cancer Research UK (C490/A16561), the Biomedical Research Centre at the University of Cambridge. The Kuopio Breast Cancer Project (KBCP) was supported by The special Government Funding of Kuopio University Hospital grants, Cancer Fund of North Savo, the Finnish Cancer Organizations, the strategic funding of the University of Eastern Finland. Funding Information: The Helsinki Breast Cancer Study (HEBCS) thanks Kristiina Aittomaki, Kirsimari Aaltonen, Taru A Muranen, Karl von Smitten, and Irja Erkkila¨ for their kind help with the patient samples and data. The Study of Epidemiology and Risk factors in Cancer Heredity (SEARCH) thanks Elena Provenzano and Marie Mack. The HEBCS was supported by The Helsinki University Central Hospital Research Fund, Academy of Finland (266528), the Finnish Cancer Society, and The Nordic Cancer Union and the Sigrid Juselius Foundation. Publisher Copyright: {\textcopyright} 2016 Cancer Research UK.",
year = "2016",
month = feb,
day = "2",
doi = "10.1038/bjc.2015.437",
language = "English (US)",
volume = "114",
pages = "298--304",
journal = "British Journal of Cancer",
issn = "0007-0920",
publisher = "Nature Publishing Group",
number = "3",
}