Tumor Infiltrating Lymphocytes and Tertiary Lymphoid Structure as Prognostic and Predictive Factor for Neoadjuvant Chemotherapy in Stage II & III Breast Cancer

Purpose: Tumor-infiltrating lymphocytes (TILs) have a strong prognostic and predictive value in triple-negative breast cancer (TNBC) and HER2 enriched subtype but no other breast subtypes but no studies have evaluated tertiary lymphoid structure (TLS). Materials and Methods: Eighty patients with stage II and III breast cancer in Tanta oncology and pathology department with luminal A, B and her 2 enriched and TNBC diagnosed with core needle biopsy treated with neoadjuvant chemotherapy (4 AC followed by 12-week taxol + herceptin). TIL and TLS were evaluated histopathologically using hematoxylin and eosin–stained slides. The immune cell aggregates which were TLS positive showed the presence of CD20+ B lymphocytes within the follicles, with areas of CD3+, CD4+ T lymphocytes mainly in the periphery [T-cell zone] resembling the highly organized structures of secondary lymphoid organs. Results: TLS were detected in 53.7% of the tumors in whole breast groups, 83.7% in triple negative subgroup. Increased number of tumor infiltrating lymphocytes and tertiary lymphoid structure are associated with longer OS and DFS for TNBC and HER2-positive breast cancer. Conclusion: For predicting treatment response in patients with TNBC and HER2 enriched subtype, TILs and TLS may be prognostic and predictive marker triplenegative breast cancer (TNBC) and HER2 enriched subtype but no other breast subtypes.