%0 Journal Article
%T Expression of the Classical and Nonclassical HLA Molecules in Breast Cancer
%A Gisela Bevilacqua Rolfsen Ferreira da Silva
%A Tarsia Giabardo Alves Silva
%A Roberta Aparecida Duarte
%A Nicolino Lia Neto
%A H¨¦lio Humberto Angotti Carrara
%A Eduardo Ant£¿nio Donadi
%A Maria Alice Guimar£¿es Gon£¿alves
%A Edson Garcia Soares
%A Christiane Pienna Soares
%J International Journal of Breast Cancer
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/250435
%X Considering that downregulation of HLA expression could represent a potential mechanism for breast carcinogenesis and metastasis, the aim of the present study was to use immunohistochemical methods to analyze the expression of HLA-Ia, HLA-DR, HLA-DQ, HLA-E, and HLA-G in invasive ductal carcinoma (IDC) of the breast and to relate this HLA profile to anatomopathological parameters. Fifty-two IDC from breast biopsies were stratified according to histological differentiation (well, moderately, and poorly differentiated) and to the presence of metastases in axillary lymph nodes. The expression of HLA molecules was assessed by immunohistochemistry, using a computer-assisted system. Overall, 31 (59.6%) out of the 52 IDC breast biopsies exhibited high expression of HLA-G, but only 14 (26.9%) showed high expression of HLA-E. A large number (41, 78.8%) of the biopsies showed low expression of HLA-Ia, while 45 (86.5%) showed high expression of HLA-DQ and 36 (69.2%) underexpressed HLA-DR. Moreover, 24 (41.2%) of 52 biopsies had both low HLA-Ia expression and high HLA-G expression, while 11 (21.2%) had low HLA-Ia expression and high HLA-E expression. These results suggest that, by different mechanisms, the downregulation of HLA-Ia, HLA-E, and HLA-DR and the upregulation of HLA-G and HLA-DQ are associated with immune response evasion and breast cancer aggressiveness. 1. Introduction Breast cancer is the commonest neoplasm and the second cause of cancer death in women worldwide. It is estimated that in the world more than one million women are diagnosed with breast cancer every year, and more than 410,000 will die from the disease, representing approximately 14% of female cancer deaths [1]. Human leukocyte antigen (HLA) class I molecules have a central role in the cell-mediated immune system, especially as antigen-presenting molecules for cytotoxic T lymphocytes (CTLs), which can recognize tumor antigenic bound peptides, presented on the cell surface with HLA class I molecules, and kill the target cell [2, 3]. HLA-I expression seems to be lost or downregulated on the tumor cell surface and this might represent a mechanism for neoplastic cells to escape from being killed by CTLs, allowing tumor dissemination and metastasis [4]. HLA class II molecules (HLA-DR and HLA-DQ) are essential for peptide presentation to T-helper lymphocytes, and their expression may be responsible for triggering the immune response. Thus, the presence of these antigens may make the tumor more immunogenic, which could lead to a favorable prognosis. However, it has been proposed that HLA-DR
%U http://www.hindawi.com/journals/ijbc/2013/250435/