Tumor Immune Microenvironment Changes by Multiplex Immunofluorescence Staining in a Pilot Study of Neoadjuvant Talazoparib for Early-Stage Breast Cancer Patients with a Hereditary BRCA Mutation

Authors

Tapsi Kumar
Evie Hobbs
Fei Yang
Jeffrey T Chang
Alejandro Contreras
Edwin Roger Parra Cuentas
Haven Garber
Sanghoon Lee
Yiling Lu
Marion E Scoggins
Beatriz E Adrada
Gary J Whitman
Banu K Arun
Elizabeth A Mittendorf
Jennifer K Litton

Publication Date

9-1-2022

Journal

Clinical Cancer Research

Abstract

PURPOSE: The immunological profile of early-stage breast cancer treated with neoadjuvant PARP inhibitors has not been described. The aim of this study was to delineate the changes in the tumor immune microenvironment (TiME) induced by talazoparib.

PATIENTS AND METHODS: Patients with operable germline BRCA1/2 pathogenic variant (gBRCA1/2+) breast cancer were enrolled in a feasibility study of neoadjuvant talazoparib. Thirteen patients who received 8 weeks of neoadjuvant talazoparib were available for analysis, including 11 paired pre- and post-talazoparib core biopsies. Treatment-related changes in tumor-infiltrating lymphocytes were examined and immune cell phenotypes and their spatial distribution in the TiME were identified and quantified by multiplex immunofluorescence using a panel of 6 biomarkers (CD3, CD8, CD68, PD-1, PD-L1, and CK).

RESULTS: Neoadjuvant talazoparib significantly increased infiltrating intratumoral and stromal T-cell and cytotoxic T-cell density. There was no difference in PD-1 or PD-L1 immune cell phenotypes in the pre- and post-talazoparib specimens and PD-L1 expression in tumor cells was rare in this cohort. Spatial analysis demonstrated that pre-talazoparib interactions between macrophages and T cells may correlate with pathologic complete response.

CONCLUSIONS: This is the first study with phenotyping to characterize the immune response to neoadjuvant talazoparib in patients with gBRCA1/2+ breast cancer. These findings support an emerging role for PARP inhibitors in enhancing tumor immunogenicity. Further investigation of combinatorial strategies is warranted with agents that exploit the immunomodulatory effects of PARP inhibitors on the TiME.

Keywords

B7-H1 Antigen, Breast Neoplasms, Female, Fluorescent Antibody Technique, Germ-Line Mutation, Humans, Lymphocytes, Tumor-Infiltrating, Neoadjuvant Therapy, Phthalazines, Pilot Projects, Poly(ADP-ribose) Polymerase Inhibitors, Programmed Cell Death 1 Receptor, Staining and Labeling, Tumor Microenvironment

Comments

Supplementary Materials

PMID: 35736816