Exploratory analysis of immune checkpoint receptor expression by circulating T cells and tumor specimens in patients receiving neo-adjuvant chemotherapy for operable breast cancer

Abstract

Background While combinations of immune checkpoint (ICP) inhibitors and neo-adjuvant chemotherapy (NAC) have begun testing in patients with breast cancer (BC), the effects of chemotherapy on ICP expression in circulating T cells and within the tumor microenvironment are still unclear. This information could help with the design of future clinical trials by permitting the selection of the most appropriate ICP inhibitors for incorporation into NAC. Methods Peripheral blood samples and/or tumor specimens before and after NAC were obtained from 24 women with operable BC. The expression of CTLA4, PD-1, Lag3, OX40, and Tim3 on circulating T lymphocytes before and at the end of NAC were measured using flow cytometry. Furthermore, using multi-color immunohistochemistry (IHC), the expression of immune checkpoint molecules by stromal tumor-infiltrating lymphocytes (TILs), CD8+ T cells, and tumor cells was determined before and after NAC. Differences in the percentage of CD4+ and CD8+ T cells expressing various checkpoint receptors were determined by a paired Student’s t-test. Results This analysis showed decreased ICP expression by circulating CD4+ T cells after NAC, including significant decreases in CTLA4, Lag3, OX40, and PD-1 (all p values < 0.01). In comparison, circulating CD8+ T cells showed a significant increase in CTLA4, Lag3, and OX40 (all p values < 0.01). Within tumor samples, TILs, CD8+ T cells, and PD-L1/PD-1 expression decreased after NAC. Additionally, fewer tumor specimens were considered to be PD-L1/PD-1 positive post-NAC as compared to pre-NAC biopsy samples using a cutoff of 1% expression. Conclusions This work revealed that NAC treatment can substantially downregulate CD4+ and upregulate CD8+ T cell ICP expression as well as deplete the amount of TILs and CD8+ T cells found in breast tumor samples. These findings provide a starting point to study the biological significance of these changes in BC patients. Trial registration NCT04022616.

An immune cell infiltration-based immune score model predicts prognosis and chemotherapy effects in breast cancer

“…Recently, a clinical trial found that the induction of chemotherapy in TNBC causes a favorable tumor immunologic microenvironment and increases sensitivity to PD-1 blockade 44 . In another study by Wesolowski et al, the authors concluded that neo-ACT influences the immune microenvironment by downregulating CD4+ and upregulating CD8+ cells, which leads to a reduction in the number of TILs and CD8+ T cells in breast cancer samples 45 . These reports are consistent with our present observations, as we observed a statistically significant potential link with chemotherapy for the METABRIC cohort.…”

PD-L1 Protein Expression Is Associated With Good Clinical Outcomes and Nomogram for Prediction of Disease Free Survival and Overall Survival in Breast Cancer Patients Received Neoadjuvant Chemotherapy

“…Previous studies have shown that PD-1 and PD-L1 protein expression were associated with the prognosis in different malignant tumors ( 33 – 35 ). However, due to significant limitations of these studies (e.g., Ahmed FS’s study ( 36 ), Wesolowski R’s study ( 37 ), and Loibl S’s study ( 38 )), research into the potential significance of PD-1 and PD-L1 protein expression in breast cancer patients treated with NACT was often considered flawed or controversial. Therefore, in light of their research and practical significance, to bridge the research gap, the present study investigated the PD-L1 protein expression in post-NACT patients’ tumor tissues and examined the relationship between the PD-L1 protein expression and patients’ treatment efficacy.…”

Modulation of Lymphocyte Functions in the Microenvironment by Tumor Oncogenic Pathways

“…Immune checkpoints (ICPs) are co-regulatory molecules controlling T cell activation and can be classified into stimulatory and inhibitory receptors. The former include CD28, CD27, ICOS, CD226, HVEM and OX40, while the latter comprise CTLA-4 (cytotoxic T lymphocyte-associated protein-4), PD1 (programmed cell death-1), TIGIT (T cell immunoreceptor with immunoglobulin and ITIM domain), VISTA (V-domain Ig suppressor of T cell activation) and LAG-3 (lymphocyte activation gene 3) ( 13 – 15 ). Some molecules, like BTLA and TIM-3 (T cell immunoglobulin and mucin domain 3), could exert both stimulatory as well as inhibitory activities depending on the cellular context ( 16 – 18 ).…”