Integrating multiplexed imaging and multiscale modeling identifies tumor phenotype conversion as a critical component of therapeutic T cell efficacy.

Cancer progression is a complex process involving interactions that unfold across molecular, cellular, and tissue scales. These multiscale interactions have been difficult to measure and to simulate. Here, we integrated CODEX multiplexed tissue imaging with multiscale modeling software to model key action points that influence the outcome of T cell therapies with cancer. The initial phenotype of therapeutic T cells influences the ability of T cells to convert tumor cells to an inflammatory, anti-proliferative phenotype. This T cell phenotype could be preserved by structural reprogramming to facilitate continual tumor phenotype conversion and killing. One takeaway is that controlling the rate of cancer phenotype conversion is critical for control of tumor growth. The results suggest new design criteria and patient selection metrics for T cell therapies, call for a rethinking of T cell therapeutic implementation, and provide a foundation for synergistically integrating multiplexed imaging data with multiscale modeling of the cancer-immune interface. A record of this paper's transparent peer review process is included in the supplemental information.

T cell-mediated curation and restructuring of tumor tissue coordinates an effective immune response.

Antigen-specific T cells traffic to, are influenced by, and create unique cellular microenvironments. Here we characterize these microenvironments over time with multiplexed imaging in a melanoma model of adoptive T cell therapy and human patients with melanoma treated with checkpoint inhibitor therapy. Multicellular neighborhood analysis reveals dynamic immune cell infiltration and inflamed tumor cell neighborhoods associated with CD8+ T cells. T cell-focused analysis indicates T cells are found along a continuum of neighborhoods that reflect the progressive steps coordinating the anti-tumor immune response. More effective anti-tumor immune responses are characterized by inflamed tumor-T cell neighborhoods, flanked by dense immune infiltration neighborhoods. Conversely, ineffective T cell therapies express anti-inflammatory cytokines, resulting in regulatory neighborhoods, spatially disrupting productive T cell-immune and -tumor interactions. Our study provides in situ mechanistic insights into temporal tumor microenvironment changes, cell interactions critical for response, and spatial correlates of immunotherapy outcomes, informing cellular therapy evaluation and engineering.

Integrating Multiplexed Imaging and Multiscale Modeling Identifies Tumor Phenotype Transformation as a Critical Component of Therapeutic T Cell Efficacy.

Cancer progression is a complex process involving interactions that unfold across molecular, cellular, and tissue scales. These multiscale interactions have been difficult to measure and to simulate. Here we integrated CODEX multiplexed tissue imaging with multiscale modeling software, to model key action points that influence the outcome of T cell therapies with cancer. The initial phenotype of therapeutic T cells influences the ability of T cells to convert tumor cells to an inflammatory, anti-proliferative phenotype. This T cell phenotype could be preserved by structural reprogramming to facilitate continual tumor phenotype conversion and killing. One takeaway is that controlling the rate of cancer phenotype conversion is critical for control of tumor growth. The results suggest new design criteria and patient selection metrics for T cell therapies, call for a rethinking of T cell therapeutic implementation, and provide a foundation for synergistically integrating multiplexed imaging data with multiscale modeling of the cancer-immune interface.

Targeting KDM2A Enhances T-cell Infiltration in NSD1-Deficient Head and Neck Squamous Cell Carcinoma.

In head and neck squamous cell carcinoma (HNSCC), a significant proportion of tumors have inactivating mutations in the histone methyltransferase NSD1. In these tumors, NSD1 inactivation is a driver of T-cell exclusion from the tumor microenvironment (TME). A better understanding of the NSD1-mediated mechanism regulating infiltration of T cells into the TME could help identify approaches to overcome immunosuppression. Here, we demonstrated that NSD1 inactivation results in lower levels of H3K36 dimethylation and higher levels of H3K27 trimethylation, the latter being a known repressive histone mark enriched on the promoters of key T-cell chemokines CXCL9 and CXCL10. HNSCC with NSD1 mutations had lower levels of these chemokines and lacked responses to PD-1 immune checkpoint blockade. Inhibition of KDM2A, the primary lysine demethylase that is selective for H3K36, reversed the altered histone marks induced by NSD1 loss and restored T-cell infiltration into the TME. Importantly, KDM2A suppression decreased growth of NSD1-deficient tumors in immunocompetent, but not in immunodeficient, mice. Together, these data indicate that KDM2A is an immunotherapeutic target for overcoming immune exclusion in HNSCC. SIGNIFICANCE: The altered epigenetic landscape of NSD1-deficient tumors confers sensitivity to inhibition of the histone-modifying enzyme KDM2A as an immunotherapeutic strategy to stimulate T-cell infiltration and suppress tumor growth.

The Effect of Black Cohosh on Ki67 expression and Tumor Volume: A Pilot Study of Ductal Carcinoma in Situ Patients.

BACKGROUND: Black cohosh (BC) (Cimicifuga racemosa) may prevent and treat breast cancer through anti-proliferative, pro-apoptotic, anti-estrogenic, and anti-inflammatory effects. This study sought to evaluate the effect of BC on tumor cellular proliferation, measured by Ki67 expression, in a pre-operative window trial of ductal carcinoma in situ (DCIS) patients. METHODS: Patients were treated pre-operatively for 2 to 6 weeks with BC extract. Eligible subjects were those who had DCIS on core biopsy. Ki67 was measured using automated quantitative immunofluorescence (AQUA) pre/post-operatively. Ki67, tumor volume, and hormone changes were assessed with 2-sided Wilcoxon signed-rank tests, α = .05. RESULTS: Thirty-one patients were treated for an average of 24.5 days (median 25; range 15-36). Ki67 decreased non-significantly (n = 26; P = .20; median pre-treatment 1280, post-treatment 859; range pre-treatment 175-7438, post-treatment 162-3370). Tumor volume, estradiol, and FSH did not change significantly. No grade 3 or 4 adverse events were reported. CONCLUSIONS: BC use showed no significant impact on cellular proliferation, tumor volume, or invasive disease upgrade rates in DCIS patients. It was well-tolerated, with no observed significant toxicities. Further study is needed to elucidate BC's role in breast cancer treatment and prevention.ClinicalTrials.gov Identifier: NCT01628536https://clinicaltrials.gov/ct2/show/NCT01628536.

Identification of Known and Novel Long Noncoding RNAs Potentially Responsible for the Effects of Bone Mineral Density (BMD) Genomewide Association Study (GWAS) Loci.

Osteoporosis, characterized by low bone mineral density (BMD), is the most common complex disease affecting bone and constitutes a major societal health problem. Genome-wide association studies (GWASs) have identified over 1100 associations influencing BMD. It has been shown that perturbations to long noncoding RNAs (lncRNAs) influence BMD and the activities of bone cells; however, the extent to which lncRNAs are involved in the genetic regulation of BMD is unknown. Here, we combined the analysis of allelic imbalance (AI) in human acetabular bone fragments with a transcriptome-wide association study (TWAS) and expression quantitative trait loci (eQTL) colocalization analysis using data from the Genotype-Tissue Expression (GTEx) project to identify lncRNAs potentially responsible for GWAS associations. We identified 27 lncRNAs in bone that are located in proximity to a BMD GWAS association and harbor single-nucleotide polymorphisms (SNPs) demonstrating AI. Using GTEx data we identified an additional 31 lncRNAs whose expression was associated (false discovery rate [FDR] correction < 0.05) with BMD through TWAS and had a colocalizing eQTL (regional colocalization probability [RCP] > 0.1). The 58 lncRNAs are located in 43 BMD associations. To further support a causal role for the identified lncRNAs, we show that 23 of the 58 lncRNAs are differentially expressed as a function of osteoblast differentiation. Our approach identifies lncRNAs that are potentially responsible for BMD GWAS associations and suggest that lncRNAs play a role in the genetics of osteoporosis. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Temporal and Quantitative Transcriptomic Differences Define Sexual Dimorphism in Murine Postnatal Bone Aging.

Time is a central element of the sexual dimorphic patterns of development, pathology, and aging of the skeleton. Because the transcriptome is a representation of the phenome, we hypothesized that both sex and sex-specific temporal, transcriptomic differences in bone tissues over an 18-month period would be informative to the underlying molecular processes that lead to postnatal sexual dimorphism. Regardless of age, sex-associated changes of the whole bone transcriptomes were primarily associated not only with bone but also vascular and connective tissue ontologies. A pattern-based approach used to screen the entire Gene Expression Omnibus (GEO) database against those that were sex-specific in bone identified two coordinately regulated gene sets: one related to high phosphate-induced aortic calcification and one induced by mechanical stimulation in bone. Temporal clustering of the transcriptome identified two skeletal tissue-associated, sex-specific patterns of gene expression. One set of genes, associated with skeletal patterning and morphology, showed peak expression earlier in females. The second set of genes, associated with coupled remodeling, had quantitatively higher expression in females and exhibited a broad peak between 3 to 12 months, concurrent with the animals' reproductive period. Results of phenome-level structural assessments of the tibia and vertebrae, and in vivo and in vitro analysis of cells having osteogenic potential, were consistent with the existence of functionally unique, skeletogenic cell populations that are separately responsible for appositional growth and intramedullary functions. These data suggest that skeletal sexual dimorphism arises through sex-specific, temporally different processes controlling morphometric growth and later coupled remodeling of the skeleton during the reproductive period of the animal. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Association of Medicaid Expansion with Post-mastectomy Reconstruction Rates.

BACKGROUND: The Affordable Care Act sought to improve access to health care for low-income individuals. This study aimed to assess whether expansion of Medicaid coverage increased rates of post-mastectomy reconstruction (PMR) for patients who had Medicaid or no insurance. METHODS: A retrospective analysis performed through the National Cancer Database examined women who underwent PMR and were uninsured or had Medicaid, private insurance, or Medicare, and whose race/ethnicity, age, and state expansion status were known. Trends in the use of PMR after passage of Medicaid expansion in 2014 were evaluated. RESULTS: In all states and at all time periods, patients with private insurance were about twice as likely to undergo PMR as patients who had Medicaid or no insurance. In 2016, only 28.7 % of patients with Medicaid or no insurance in nonexpansion states underwent PMR (p < 0.001) compared with 38.5 % of patients in expansion states (p < 0.001). Patients in expansion states also have higher levels of education, higher income, and greater likelihood of living in metropolitan areas. Additionally, patients in all states saw an increase in early-stage disease, with a concomitant reduction in late disease, but this change was greater in expansion states than in non-expansion states. CONCLUSIONS: Expansion states have larger proportions of patients undergoing PMR than non-expansion states. This difference stems from significant differences in income, education, comorbidities, race, and location. Large metropolitan areas have the largest number of patients undergoing PMR, whereas rural areas have the least.

Apocrine Breast Cancer: Unique Features of a Predominantly Triple-Negative Breast Cancer.

INTRODUCTION: Invasive apocrine carcinoma is a rare breast cancer that is frequently triple negative. Little is known about the characteristics of its molecular subtypes. We compared the incidence, demographics, and clinicopathologic features of this cancer with non-apocrine carcinomas stratified by molecular subtype. METHODS: Women with invasive apocrine cancer were retrospectively identified from the Surveillance, Epidemiology, and End Results (SEER) database. Clinicopathologic and demographic features were compared with non-apocrine carcinomas, both overall using data from 2004 to 2017 and stratified by molecular subtypes using data from 2010 to 2017. The life table method was used to determine the 7-year breast cancer-specific survival. RESULTS: Compared with non-apocrine cancers, apocrine cancers presented at a younger age, with larger, higher-grade tumors that were much more likely to be triple negative (50% vs. 11%) or human epidermal growth factor receptor 2 (HER2)-positive (28% vs. 15%) and less likely to be luminal (22% vs. 74%); however, the 7-year survival was the same at 85%. The characteristics varied dramatically by molecular type. Compared with non-apocrine triple-negative, apocrine triple-negative patients were less likely to be African American and were much older, with smaller, lower-grade tumors and much better survival (86% vs. 74%). In contrast, compared with luminal non-apocrine, apocrine luminal patients had larger, higher-grade tumors and worse survival (79% vs. 89%). CONCLUSIONS: Invasive apocrine carcinomas have more aggressive features than non-apocrine carcinomas but the breast cancer-specific survival is the same. Half of these apocrine tumors are triple negative but these have more favorable features and much better survival than non-apocrine triple-negative cancers.

Landscape of innate lymphoid cells in human head and neck cancer reveals divergent NK cell states in the tumor microenvironment.

Natural killer (NK) cells comprise one subset of the innate lymphoid cell (ILC) family. Despite reported antitumor functions of NK cells, their tangible contribution to tumor control in humans remains controversial. This is due to incomplete understanding of the NK cell states within the tumor microenvironment (TME). Here, we demonstrate that peripheral circulating NK cells differentiate down two divergent pathways within the TME, resulting in different end states. One resembles intraepithelial ILC1s (ieILC1) and possesses potent in vivo antitumor activity. The other expresses genes associated with immune hyporesponsiveness and has poor antitumor functional capacity. Interleukin-15 (IL-15) and direct contact between the tumor cells and NK cells are required for the differentiation into CD49a+CD103+ cells, resembling ieILC1s. These data explain the similarity between ieILC1s and tissue-resident NK cells, provide insight into the origin of ieILC1s, and identify the ieILC1-like cell state within the TME to be the NK cell phenotype with the greatest antitumor activity. Because the proportions of the different ILC states vary between tumors, these findings provide a resource for the clinical study of innate immune responses against tumors and the design of novel therapy.

Humanized Mouse Models for the Advancement of Innate Lymphoid Cell-Based Cancer Immunotherapies.

Innate lymphoid cells (ILCs) are a branch of the immune system that consists of diverse circulating and tissue-resident cells, which carry out functions including homeostasis and antitumor immunity. The development and behavior of human natural killer (NK) cells and other ILCs in the context of cancer is still incompletely understood. Since NK cells and Group 1 and 2 ILCs are known to be important for mediating antitumor immune responses, a clearer understanding of these processes is critical for improving cancer treatments and understanding tumor immunology as a whole. Unfortunately, there are some major differences in ILC differentiation and effector function pathways between humans and mice. To this end, mice bearing patient-derived xenografts or human cell line-derived tumors alongside human genes or human immune cells represent an excellent tool for studying these pathways in vivo. Recent advancements in humanized mice enable unparalleled insights into complex tumor-ILC interactions. In this review, we discuss ILC behavior in the context of cancer, the humanized mouse models that are most commonly employed in cancer research and their optimization for studying ILCs, current approaches to manipulating human ILCs for antitumor activity, and the relative utility of various mouse models for the development and assessment of these ILC-related immunotherapies.

Neoadjuvant durvalumab plus weekly nab-paclitaxel and dose-dense doxorubicin/cyclophosphamide in triple-negative breast cancer.

The goal of this Phase I/II trial is to assess the safety and efficacy of administering durvalumab concurrent with weekly nab-paclitaxel and dose-dense doxorubicin/cyclophosphamide (ddAC) neoadjuvant therapy for stages I-III triple-negative breast cancer. The primary endpoint is pathologic complete response (pCR:ypT0/is, ypN0). The response was correlated with PDL1 expression and stromal tumor-infiltrating lymphocytes (sTILs). Two dose levels of durvalumab (3 and 10 mg/kg) were assessed. PD-L1 was assessed using the SP263 antibody; ≥1% immune and tumor cell staining was considered positive; sTILs were calculated as the area occupied by mononuclear inflammatory cells over the total intratumoral stromal area. 59 patients were evaluable for toxicity and 55 for efficacy in the Phase II study (10 mg/kg dose). No dose-limiting toxicities were observed in Phase I. In Phase II, pCR rate was 44% (95% CI: 30-57%); 18 patients (31%) experienced grade 3/4 treatment-related adverse events (AE), most frequently neutropenia (n = 4) and anemia (n = 4). Immune-related grade 3/4 AEs included Guillain-Barre syndrome (n = 1), colitis (n = 2), and hyperglycemia (n = 2). Of the 50 evaluable patients for PD-L1, 31 (62%) were PD-L1 positive. pCR rates were 55% (95% CI: 0.38-0.71) and 32% (95% CI: 0.12-0.56) in the PD-L1 positive and negative groups (p = 0.15), respectively. sTIL counts were available on 52 patients and were significantly higher in the pCR group (p = 0.0167). Concomitant administration of durvalumab with sequential weekly nab-paclitaxel and ddAC neoadjuvant chemotherapy resulted in a pCR rate of 44%; pCR rates were higher in sTIL-high cancers.

The impact of communication style on patient satisfaction.

BACKGROUND: Communication between patients and health providers influences patient satisfaction, but it is unknown whether similarity in communication styles results in higher patient satisfaction. METHODS: This study was conducted in the Smilow Cancer Hospital Breast Center. During routine follow-up visits, patients completed a Communication Styles Assessment (CSA), health survey (SF-12), Princess Margaret Hospital Satisfaction with Doctor Questionnaire, and brief demographic form. Physicians and Advanced Practice Providers were also asked to complete the CSA. Patients and providers were blinded to each other's responses. A communication styles concordance score was calculated as the Pearson correlation between 80 binary CSA items for each provider/patient pair. Factors affecting patient satisfaction scores were assessed in mixed-effects models. RESULTS: In total, 330 patients were invited to participate; of these 289 enrolled and 245 returned surveys. One hundred seventy-four completed all survey components, and 18 providers completed the CSA. Among the factors considered, physical health score (effect size = 0.0058, 95% CI 0.00051 to 0.0011, p = 0.032) and employment status (0.12, 95% CI - 0.0094 to 0.25, p = 0.069) had the greatest impact on patient satisfaction. However, patients who were not employed and less physically healthy had significantly elevated satisfaction scores when their communication style was more similar to their provider's (1.52, 95% CI 0.66 to 2.38, p = 0.0016). CONCLUSIONS: Patients who were physically healthy and employed were generally more satisfied with their care. The similarity in communication styles of patients and providers had a greater impact on patient satisfaction for patients who were less physically healthy and not employed.

Patient-Reported Outcomes and Cosmesis in a Feasibility Study of 4-Dimensional Simulated Image Guided Accelerated Partial Breast Irradiation.

PURPOSE: Three-dimensional conformal accelerated partial breast irradiation (APBI) is a treatment option for well selected women with breast cancer, despite reports of adverse cosmetic outcome with this technique. Dose-volume relationships may be responsible for this poor cosmesis. We aimed to determine the feasibility of limiting the exposure of nontarget breast tissue to radiation through smaller planning target volumes achieved through daily image guidance and 4-dimensional computed tomography simulation. METHODS AND MATERIALS: Eligibility criteria included the following: women, age ≥50 years, Karnofsky performance status score ≥70, stage 0 and I breast cancer treated with breast-conserving surgery, margins clear by ≥2 mm, pathologic tumor size ≤2 cm, and 4-dimensional computed tomography with planning target volumes of 0.2 cm rather than the standard 1.0 cm. A dose of 3850 cGy was prescribed in 10 fractions. The study was considered successful if ≥50% of enrollees met dosimetric constraints on the breast (V50 < 45% and V100 < 23.5%). RESULTS: The study achieved its primary endpoint of feasibility of reducing the nontarget breast dose with a breast median of V50 = 31% and V100 = 11%. There were no recurrences and no toxicity grade >3. At baseline, fair/poor cosmesis was low (2.2%). By year 3, adverse cosmesis post-APBI had increased by 13.2% (to 15.4%). Patient decisional satisfaction was reached completely in 84.2% of patients. CONCLUSIONS: This study demonstrated that with 4-dimensional simulated APBI that uses stringent dosimetric constraints and image guidance radiation therapy, it is possible to obtain acceptable cosmetic outcomes. We report no locoregional recurrences in 3 years and no toxicity grade >3. The observed decline in cosmesis was acceptable compared with that of prior published studies, and patient satisfaction with APBI was excellent.

Long-Term Survival of De Novo Stage IV Human Epidermal Growth Receptor 2 (HER2) Positive Breast Cancers Treated with HER2-Targeted Therapy.

BACKGROUND: An increasing proportion of human epidermal growth receptor 2 (HER2) positive (HER2+) metastatic breast cancer (MBC) is diagnosed as de novo stage IV disease. We hypothesize that a subset of these patients who achieve no evidence of disease (NED) status after multimodality HER2-targeted treatments may have prolonged progression-free survival (PFS) and overall survival (OS). MATERIALS AND METHODS: Patients with de novo stage IV, HER2+ MBC (n = 483) diagnosed between 1998 and 2015 were identified at two institutions (Yale and MD Anderson Cancer Centers). Clinical variables, treatment details, and survival outcomes were compared between those who achieved NED and those who did not. RESULTS: All patients received trastuzumab, and 20% also received pertuzumab as first-line therapy. The median OS was 5.5 years (95% confidence interval [Cl]: 4.8-6.2). Sixty-three patients (13.0%) achieved NED; their PFS and OS rates were 100% and 98% (95% CI: 94.6%-100%), respectively, at 5 years and remained the same at 10 years. For patients with no NED (n = 420), the PFS and OS rates were 12% (95% CI: 4.5%-30.4%) and 45% (95% CI: 38.4%-52.0%) at 5 years and 0% and 4% (95% CI, 1.3%-13.2%) at 10 years, respectively. NED patients more frequently had solitary metastasis (79% vs. 51%, p = .005) and surgery to resect cancer (59% vs. 22%, p ≤ .001). In multivariate analysis, NED status (hazard ratio [HR]: 0.014, p = .0002) and estrogen receptor positive status (HR: 0.72; p = .04) were associated with prolonged OS. CONCLUSION: Among patients with de novo stage IV, HER2+ MBC, those who achieve NED status have a very high PFS and OS. Further randomized studies are required to fully understand the impact of systemic or locoregional therapy on achieving these excellent long-term outcomes. IMPLICATIONS FOR PRACTICE: In this retrospective review at two institutions, it was demonstrated that 13% of patients with de novo stage IV, human epidermal growth receptor 2 positive metastatic breast cancer achieved no evidence of disease (NED) status with trastuzumab-based therapy plus/minus local therapies, and these patients had a very high progression-free survival (100%) and overall survival (98%) at both the 5- and 10-year time points. Achieving NED status may be an important therapeutic goal. However, further randomized studies are required to fully understand the impact of systemic or locoregional therapy on achieving these excellent long-term outcomes.

Hypophosphatemia Regulates Molecular Mechanisms of Circadian Rhythm.

Transcriptomic analysis showed that the central circadian pathway genes had significantly altered expression in fracture calluses from mice fed a low phosphate diet. This led us to hypothesize that phosphate deficiency altered the circadian cycle in peripheral tissues. Analysis of the expression of the central clock genes over a 24-36 hour period in multiple peripheral tissues including fracture callus, proximal tibia growth plate and cardiac tissues after 12 days on a low phosphate diet showed higher levels of gene expression in the hypophosphatemia groups (p < 0.001) and a 3 to 6 hour elongation of the circadian cycle. A comparative analysis of the callus tissue transcriptome genes that were differentially regulated by hypophosphatemia with published data for the genes in bone that are diurnally regulated identified 1879 genes with overlapping differential regulation, which were shown by ontology assessment to be associated with oxidative metabolism and apoptosis. Network analysis of the central circadian pathway genes linked their expression to the up regulated expression of the histone methyltransferase gene EZH2, a gene that when mutated in both humans and mice controls overall skeletal growth. These data suggest that phosphate is an essential metabolite that controls circadian function in both skeletal and non skeletal peripheral tissues and associates its levels with the overall oxidative metabolism and skeletal growth of animals.

Single-arm, neoadjuvant, phase II trial of pertuzumab and trastuzumab administered concomitantly with weekly paclitaxel followed by 5-fluoruracil, epirubicin, and cyclophosphamide (FEC) for stage I-III HER2-positive breast cancer.

PURPOSE: The purpose of this two-cohort Phase II trial was to estimate the pathologic complete response (pCR: ypT0/is ypN0) rate when trastuzumab plus pertuzumab are administered concurrently during both the taxane and anthracycline phases of paclitaxel and 5-fluorouracil/epirubicin/cyclophosphamide (FEC) neoadjuvant chemotherapy. METHODS: The pCR rates were assessed separately in hormone receptor (HR) positive and negative cases following Simon's two-stage design, aiming to detect a 20% absolute improvement in pCR rates from 50 to 70 and 70 to 90% in the HR-positive and HR-`negative cohorts, respectively. RESULTS: The HR-negative cohort completed full accrual of 26 patients; pCR rate was 80% (95% CI 60-91%). The HR+ cohort was closed early after 24 patients due to lower than expected pCR rate of 26% (95% CI 13-46%) at interim analysis. Overall, 44% of patients (n = 22/50) experienced grade 3/4 adverse events. The most common were neutropenia (n = 10) and diarrhea (n = 7). There was no symptomatic heart failure, but 28% (n = 14) had ≥ 10% asymptomatic decrease in LVEF; in one patient, LVEF decreased to < 50%. Cardiac functions returned to baseline by the next assessment in 57% (8/14) of cases. CONCLUSIONS: Eighty percent of HR-negative, HER2-positive breast cancers achieve pCR with paclitaxel/FEC neoadjuvant chemotherapy administered concomitantly with pertuzumab and trastuzumab. These results are similar to pCR rates seen in trials using HER2-targeted therapy during the taxane phase only of sequential taxane-anthracycline regimens and suggest that we have reached a therapeutic plateau with HER2-targeted therapies combined with chemotherapy in the neoadjuvant setting.