50P - Lymphocytes infiltrating breast cancer : density, composition and organization

Date 08 May 2014
Event IMPAKT 2014
Session Welcome reception and Poster Walk
Topics Breast Cancer
Pathology/Molecular Biology
Presenter Laurence Buisseret
Citation Annals of Oncology (2014) 25 (suppl_1): i17-i18. 10.1093/annonc/mdu067
Authors L. Buisseret1, S. Garaud2, H. Duvillier2, C. Naveaux2, S. Duquenne3, A. De Wind3, J. Vakili4, C. Sotiriou5, K. Willard-Gallo2
  • 1Medicine, Institut Jules Bordet, Université Libre de Bruxelles, 1000 - Brussels/BE
  • 2Molecular Immunology, Institut Jules Bordet, Université Libre de Bruxelles, 1000 - Brussels/BE
  • 3Pathology, Institut Jules Bordet, Université Libre de Bruxelles, 1000 - Brussels/BE
  • 4Recherche Clinique, Institut Jules Bordet, 1000 - Brussels/BE
  • 5Bctl - Breast Cancer Translational Research Laboratory, Institut Jules Bordet, Université Libre de Bruxelles, 1000 - Brussels/BE

Abstract

The clinical relevance of tumor infiltrating lymphocytes (TIL) in breast cancer (BC) is controversial due to variation in the subpopulations of immune cells detected in tumors, with the balance of key players potentially explaining the protective immunity observed in some patients. To gain insight, we performed comprehensive immunophenotyping of T and B-TIL in early stage BC. This prospective analysis used flow cytometry to examine TIL in fresh tumor homogenates (n121). TIL were compared to lymphocytes in nonadjacent non-tumor breast tissue (NANT, n116) and normal tissue from mammary reductions (n28). TIL organization and spatial distribution was analyzed by immunohistochemistry and immunofluorescence on paraffin sections from a subset of patients (n78). The fresh tissue analyses revealed that tumors have a higher TIL density compared to normal tissue and NANT, the latter two being remarkably similar and thus used to establish a cutoff for TIL positive tumors. Using this threshold, 65 of the tumors were TIL positive. TIL density was correlated with proliferation (Ki-67 & histological grade) and inversely correlated with hormone receptor expression. Tumors have higher frequencies of lymphocytes compared with normal tissue, with associated increases in CD4 T cells and CD19 B cells. The frequency of CD4 T cells is higher in TIL positive tumors with a median CD4/CD8 ratio>1 compared to