Comprehensive Analysis of the Immunogenomics of Triple-Negative Breast Cancer Brain Metastases From LCCC1419.

Background: Triple negative breast cancer (TNBC) is an aggressive variant of breast cancer that lacks the expression of estrogen and progesterone receptors (ER and PR) and HER2. Nearly 50% of patients with advanced TNBC will develop brain metastases (BrM), commonly with progressive extracranial disease. Immunotherapy has shown promise in the treatment of advanced TNBC; however, the immune contexture of BrM remains largely unknown. We conducted a comprehensive analysis of TNBC BrM and matched primary tumors to characterize the genomic and immune landscape of TNBC BrM to inform the development of immunotherapy strategies in this aggressive disease. Methods: Whole-exome sequencing (WES) and RNA sequencing were conducted on formalin-fixed, paraffin-embedded samples of BrM and primary tumors of patients with clinical TNBC (n = 25, n = 9 matched pairs) from the LCCC1419 biobank at UNC-Chapel Hill. Matched blood was analyzed by DNA sequencing as a comparison for tumor WES for the identification of somatic variants. A comprehensive genomics assessment, including mutational and copy number alteration analyses, neoantigen prediction, and transcriptomic analysis of the tumor immune microenvironment were performed. Results: Primary and BrM tissues were confirmed as TNBC (23/25 primaries, 16/17 BrM) by immunohistochemistry and of the basal intrinsic subtype (13/15 primaries and 16/19 BrM) by PAM50. Compared to primary tumors, BrM demonstrated a higher tumor mutational burden. TP53 was the most frequently mutated gene and was altered in 50% of the samples. Neoantigen prediction showed elevated cancer testis antigen- and endogenous retrovirus-derived MHC class I-binding peptides in both primary tumors and BrM and predicted that single-nucleotide variant (SNV)-derived peptides were significantly higher in BrM. BrM demonstrated a reduced immune gene signature expression, although a signature associated with fibroblast-associated wound healing was elevated in BrM. Metrics of T and B cell receptor diversity were also reduced in BrM. Conclusions: BrM harbored higher mutational burden and SNV-derived neoantigen expression along with reduced immune gene signature expression relative to primary TNBC. Immune signatures correlated with improved survival, including T cell signatures. Further research will expand these findings to other breast cancer subtypes in the same biobank. Exploration of immunomodulatory approaches including vaccine applications and immune checkpoint inhibition to enhance anti-tumor immunity in TNBC BrM is warranted.

A prospective randomized trial of standard versus multimedia-supplemented counseling in patients undergoing endometrial cancer staging surgery.

OBJECTIVES: A patient's understanding of surgery is often limited, especially in the setting of complex oncologic procedures. The use of supplemental materials can improve patients' knowledge of their procedure and satisfaction with decision making. We sought to determine if a multimedia-supplemented approach in patients undergoing robotic endometrial cancer staging improves satisfaction with preoperative counseling. Secondary objectives were patient comprehension, physician satisfaction, and visit length. METHODS: From 2018 to 2019, patients were randomized to standard physician education (SPE) or multimedia-based education (MBE), which included watching two novel videos followed by focused physician counseling. Basic demographic information was collected. Patient satisfaction was assessed using the Client Satisfaction Questionnaire-8 (CSQ-8, a validated satisfaction survey, scored 8-32) and a global satisfaction score (GGS, 10-point scale). Physician satisfaction was assessed using a GGS. Comprehension was assessed with a study-specific 9-question survey at three time points. t-tests and linear mixed models were used to compare groups. RESULTS: Of the 75 patients included in the analysis, the majority were white (70%), 50-70 years old (72%), and had at least some college education (74%). The MBE group reported higher satisfaction on the CSQ-8 (31.69 vs 30.69, p < 0.01) and global satisfaction score (9.95 vs 9.74, p = 0.04). There was no difference in comprehension scores over time (p = 0.84) or between groups (p = 0.23). Visit lengths were significantly longer in the MBE group (90.36 vs 80.46 min, p = 0.04). CONCLUSIONS: Patients had high satisfaction and comprehension with both SPE and MBE. Multimedia education may be implemented in preoperative counseling based on provider preference and consideration should be made for further study of satisfaction, both patient and physician, and visit length after the initial implementation period.

Evaluating the efficacy of a priming dose of cyclophosphamide prior to pembrolizumab to treat metastatic triple negative breast cancer.

PURPOSE: Triple negative breast cancer (TNBC) is characterized by the presence of immune cells in the tumor microenvironment, however, the response to single-agent immune checkpoint inhibitor (ICI) therapy is modest. Preclinical models have demonstrated that intratumoral regulatory T cells (Tregs) dampen the antitumor response to ICI. We performed a single-arm phase II trial to evaluate the efficacy of a single low dose of cyclophosphamide (Cy) to deplete Tregs administered before initiating pembrolizumab. PATIENTS AND METHODS: 40 patients with pretreated metastatic TNBC were enrolled. The primary endpoints were progression-free survival (PFS) and change in peripheral blood Tregs after Cy. Secondary endpoints included overall response rate (ORR), duration of response, overall survival, treatment-related adverse events (AEs), and correlative evaluations. RESULTS: Median PFS was 1.8 months, and the ORR was 21%. Tregs were not significantly decreased after Cy prior to ICI (-3.3%, p=0.19), and increased significantly after the first cycle of therapy (+21% between cycles 1 and 2, p=0.005). Immune-related AEs were similar to historical pembrolizumab monotherapy, and were associated with response to therapy (p=0.02). Patients with pretreatment tumors harboring increased expression of B cell metagene signatures and increased circulating B cell receptor repertoire diversity were associated with clinical response and immune-related toxicity (IRT). CONCLUSIONS: Among patients with heavily pretreated TNBC, Cy prior to pembrolizumab did not significantly deplete Tregs, and in those with decreased numbers there was rapid recovery following therapy. Increased B cell gene expression in baseline samples was associated with clinical response and IRT.