Influence of mutagenic versus non-mutagenic pre-operative chemotherapy on the immune infiltration of breast cancer

Background: Chemotherapeutic agents are often mutagenic. Induction of mutation associated neo-epitopes is one of the mechanisms by which chemotherapy is thought to increase the number of tumor-infiltrating lymphocytes, but the clinical relevance of this triggered immune response is not known. We decided to investigate, whether treatment with various chemotherapeutic agents with significantly different mutagenic capacity induce a significantly different number of stromal tumor-infiltrating lymphocytes (StrTIL) in the clinical setting. Methods: 112 breast carcinoma cases treated with pre-operative chemotherapy were selected for the study. According to chemotherapy regimen 28/112 patients received platinum-based, 42/112 cyclophosphamide-based and 42/112 anthracycline-based chemotherapy. The percentage of stromal tumor-infiltrating lymphocytes (StrTIL) was evaluated on hematoxylineosin stained slides of pre-treatment core biopsy (pre-StrTIL) and post-treatment surgical tumor samples (post-StrTIL), according to the most recent recommendation of International TILs Working Group. In survival analyses, TIL changes (ΔStrTIL) were calculated from the difference between post-StrTIL and pre-StrTIL. Results: Of the 112 cases, 58.0% (n=65) w...Continue Reading