Tumor-Infiltrating Lymphocytes in Breast Cancer. Association with Clinical and Pathological Parameters

Area of Science:

• Immunology
• Oncology
• Cell Biology

Background:

• The tumor microenvironment in breast cancer involves complex immune cell interactions.
• Understanding lymphocyte subsets and their roles is crucial for predicting prognosis and treatment response.

Purpose of the Study:

• To investigate the correlations between immune cell populations (CD16+, CD4+CD25+CD127-, CD8+ T cells) and tumor characteristics (Ki-67, hormone receptor status, tumor load) in primary resectable breast cancer.

Main Methods:

• Flow cytometry analysis of lymphocyte subsets in tumor-infiltrating lymphocytes.
• Assessment of tumor proliferative activity using Ki-67.
• Correlation analysis with patient age, tumor load, and estrogen/progesterone receptor (ER/PR) status.

Main Results:

• A positive correlation was found between patient age and CD16+ lymphocyte count.
• Increased Ki-67 (tumor proliferation) correlated with reduced effector lymphocytes (CD8+, CD16+) and increased regulatory CD8+ T cells.
• Estrogen receptor-negative (ER-) breast cancer showed reduced CD8+ T cell cytotoxic potential compared to ER+.
• Progesterone receptor-positive (PR+) tumors had a higher percentage of infiltrating CD8+ lymphocytes.
• Tumor load negatively impacted CD16+ lymphocyte numbers and their cytotoxic potential.

Conclusions:

• Immune cell profiles, including CD16+ lymphocytes and regulatory T cells, are associated with tumor characteristics and patient age in breast cancer.
• Tumor proliferation and hormone receptor status influence the cytotoxic capacity of tumor-infiltrating lymphocytes.
• Increasing tumor burden diminishes the number and function of CD16+ lymphocytes, suggesting immune evasion mechanisms.