Tumor-Infiltrating Lymphocytes/Plasmocytes in Chemotherapeutically Non-Influenced Triple-Negative Breast Cancers -...

Triple-negative breast cancers (TNBCs) are considered a morphologically heterogeneous group of breast carcinomas characterized by the absence or low protein expression of hormone receptors and HER2/neu/ERBB2 with a specific biological behavior and therapeutic response. This study aimed to evaluate correlations of the density of tumor-infiltrating lymphocytes/plasmocytes (TILs) in the tumor parenchyma, stroma, and invasive margins with tumor morphology, the proliferation rate, Bcl-2 expression, and selected clinical and pathological parameters in early breast cancer patients prior to mastectomy who had not received initial chemotherapy.

Samples of 3,544 breast cancer patients investigated in our department between 2007 and 2017 were re-examined. In total, 413 (11.65%) patients were diagnosed with TNBC. Only 61 cases did not undergo neoadjuvant therapy prior to mastectomy. Correlations between the density of TILs and tumor morphology, Bcl-2 expression, proliferative activity measured by Ki-67, patient age at diagnosis, tumor grade, and metastases were investigated.

The samples were predominantly relatively well-localized invasive carcinomas of no special type with medullary features (80.32%) that measured on average 13.4mm (range 5-20mm, median 15mm) and exhibited central necrosis or fibrosis, a tendency to undergo spindle cell and/or apocrine-like differentiation, and intensive infiltration of TILs. There were significant positive correlations between TILs and premenopausal status (p=0.003), Ki-67 expression (p=0.015), and tumor grade (p=0.002), a marginal positive correlation between TILs and tumor size (p=0.065), and a significant negative correlation between TILs and Bcl-2 expression (p=0.035). In younger patients (< 50 years) with tumor size less than or equal to 20 mm (pT1a-pT1c) we recorded a lower number of women with metastatic lymph node involvement (p=0.001).

The density and location of TILs in non-therapeutically influenced TNBCs, evaluated in the context of morphological changes and other clinicopathological parameters, may have prognostic significance and assist effective therapy planning.