Lymphoid environment in molecular subtypes ofbreast cancer.

Abstract

Recently, alarge body ofevidence has shown that themicroenvironment ofinvasive breast carcinoma affects its development and thepatient's outcome, and vice versa - cancer cells express factors that modulate tumour milieu in terms ofits composition and function. We performed animmunohistochemical (IHC) staining of108 formalin-fixed, paraffin-embedded (FFPE) tissue samples to investigate therelationships between T-cell, B-cell, and NK-cell infiltrate, invasive breast carcinomas molecular subtypes, and other prognostic indicators. Themain findings ofour study were as follows: thesignificantly higher infiltrate oftheanalysed immune cell subsets in triple-negative (TNBC), HER2-positive, non-luminal and luminal B/HER2+ breast carcinomas than in luminal Acancers; their higher densities in poorly differentiated lesions; correlations between lymphoid cells and theexpression ofhormonal receptors, HER2 receptor status, and marker ofcancer proliferation. Furthermore, we observed T-cell numbers to be associated with greater tumour diameter. In summary, theresults ofour study indicate associations between tumoural lymphoid infiltration and theunfavourable intrinsic subtypes as well as other detrimental prognostic factors in invasive breast carcinomas.