Tumor-infiltrating lymphocytes in HER2-positive breast cancer treated with neoadjuvant chemotherapy and dual HER2-blockade

Tumor-infiltrating lymphocytes (TILs) have been associated with outcomes in HER2-positive breast cancer patients treated with neoadjuvant chemotherapy and trastuzumab. However, it remains unclear if TILs could be a prognostic and/or predictive biomarker in the context of dual HER2-targeting treatment. In this study, we evaluated the association between TILs and pathological response (pCR) and invasive-disease free survival (IDFS) in 389 patients with stage II-III HER2 positive breast cancer who received neoadjuvant anthracycline-containing or anthracycline-free chemotherapy combined with trastuzumab and pertuzumab in the TRAIN-2 trial. Although no significant association was seen between TILs and pCR, patients with TIL scores ≥60% demonstrated an excellent 3-year IDFS of 100% (95% CI 100-100), regardless of hormone receptor status, nodal stage and attainment of pCR. Additionally, in patients with hormone receptor positive disease, TILs as a continuous variable showed a trend to a positive association with pCR (adjusted Odds Ratio per 10% increase in TILs 1.15, 95% CI 0.99-1.34, p = 0.070) and IDFS (adjusted Hazard Ratio per 10% increase in TILs 0.71, 95% CI 0.50-1.01, p = 0.058). We found no interactions between TILs and anthracycline treatment. Our results suggest that high TIL scores might be able to identify stage II-III HER2-positive breast cancer patients with a favorable prognosis.

Prognostic value of histopathologic traits independent of stromal tumor-infiltrating lymphocyte levels in chemotherapy-naïve patients with triple-negative breast cancer

BACKGROUND

In the absence of prognostic biomarkers, most patients with early-stage triple-negative breast cancer (eTNBC) are treated with combination chemotherapy. The identification of biomarkers to select patients for whom treatment de-escalation or escalation could be considered remains an unmet need. We evaluated the prognostic value of histopathologic traits in a unique cohort of young, (neo)adjuvant chemotherapy-naïve patients with early-stage (stage I or II), node-negative TNBC and long-term follow-up, in relation to stromal tumor-infiltrating lymphocytes (sTILs) for which the prognostic value was recently reported.

MATERIALS AND METHODS

We studied all 485 patients with node-negative eTNBC from the population-based PARADIGM cohort which selected women aged <40 years diagnosed between 1989 and 2000. None of the patients had received (neo)adjuvant chemotherapy according to standard practice at the time. Associations between histopathologic traits and breast cancer-specific survival (BCSS) were analyzed with Cox proportional hazard models.

RESULTS

With a median follow-up of 20.0 years, an independent prognostic value for BCSS was observed for lymphovascular invasion (LVI) [adjusted (adj.) hazard ratio (HR) 2.35, 95% confidence interval (CI) 1.49-3.69], fibrotic focus (adj. HR 1.61, 95% CI 1.09-2.37) and sTILs (per 10% increment adj. HR 0.75, 95% CI 0.69-0.82). In the sTILs <30% subgroup, the presence of LVI resulted in a higher cumulative incidence of breast cancer death (at 20 years, 58%; 95% CI 41% to 72%) compared with when LVI was absent (at 20 years, 32%; 95% CI 26% to 39%). In the ≥75% sTILs subgroup, the presence of LVI might be associated with poor survival (HR 11.45, 95% CI 0.71-182.36, two deaths). We confirm the lack of prognostic value of androgen receptor expression and human epidermal growth factor receptor 2 -low status.

CONCLUSIONS

sTILs, LVI and fibrotic focus provide independent prognostic information in young women with node-negative eTNBC. Our results are of importance for the selection of patients for de-escalation and escalation trials.

ESMO expert consensus statements (ECS) on the definition, diagnosis, and management of HER2-low breast cancer

Human epidermal growth factor receptor 2 (HER2)-low breast cancer has recently emerged as a targetable subset of breast tumors, based on the evidence from clinical trials of novel anti-HER2 antibody-drug conjugates. This evolution has raised several biological and clinical questions, warranting the establishment of consensus to optimally treat patients with HER2-low breast tumors. Between 2022 and 2023, the European Society for Medical Oncology (ESMO) held a virtual consensus-building process focused on HER2-low breast cancer. The consensus included a multidisciplinary panel of 32 leading experts in the management of breast cancer from nine different countries. The aim of the consensus was to develop statements on topics that are not covered in detail in the current ESMO Clinical Practice Guideline. The main topics identified for discussion were (i) biology of HER2-low breast cancer; (ii) pathologic diagnosis of HER2-low breast cancer; (iii) clinical management of HER2-low metastatic breast cancer; and (iv) clinical trial design for HER2-low breast cancer. The expert panel was divided into four working groups to address questions relating to one of the four topics outlined above. A review of the relevant scientific literature was conducted in advance. Consensus statements were developed by the working groups and then presented to the entire panel for further discussion and amendment before voting. This article presents the developed statements, including findings from the expert panel discussions, expert opinion, and a summary of evidence supporting each statement.

Unleashing NK- and CD8 T cells by combining monalizumab and trastuzumab for metastatic HER2-positive breast cancer: Results of the MIMOSA trial

The large majority of patients with HER2-positive metastatic breast cancer (MBC) will eventually develop resistance to anti-HER2 therapy and die of this disease. Despite, relatively high levels of stromal tumor infiltrating lymphocytes (sTILs), PD1-blockade has only shown modest responses. Monalizumab targets the inhibitory immune checkpoint NKG2A, thereby unleashing NK- and CD8 T cells. We hypothesized that monalizumab synergizes with trastuzumab by promoting antibody-dependent cell-mediated cytotoxicity. In the phase II MIMOSA-trial, HER2-positive MBC patients were treated with trastuzumab and 750 mg monalizumab every two weeks. Following a Simon's two-stage design, 11 patients were included in stage I of the trial. Treatment was well tolerated with no dose-limiting toxicities. No objective responses were observed. Therefore, the MIMOSA-trial did not meet its primary endpoint. In summary, despite the strong preclinical rationale, the novel combination of monalizumab and trastuzumab does not induce objective responses in heavily pre-treated HER2-positive MBC patients.

PRECISION: the Belgian molecular profiling program of metastatic cancer for clinical decision and treatment assignment

PRECISION is an initiative from the Belgian Society of Medical Oncology (BSMO) in collaboration with several stakeholders, encompassing four programs that aim to boost genomic and clinical knowledge with the ultimate goal to offer patients with metastatic solid tumors molecularly guided treatments. The PRECISION 1 study has led to the creation of a clinico-genomic database. The Belgian Approach for Local Laboratory Extensive Tumor Testing (BALLETT) and GeNeo studies will increase the number of patients with advanced cancer that have comprehensive genotyping of their cancer. The PRECISION 2 project consists of investigator-initiated phase II studies aiming to provide access to a targeted drug for patients whose tumors harbor actionable mutations in case the matched drug is not available through reimbursement or clinical trials in Belgium.

Aligning tumor mutational burden (TMB) quantification across diagnostic platforms: phase II of the Friends of Cancer Research TMB Harmonization Project

BACKGROUND

Tumor mutational burden (TMB) measurements aid in identifying patients who are likely to benefit from immunotherapy; however, there is empirical variability across panel assays and factors contributing to this variability have not been comprehensively investigated. Identifying sources of variability can help facilitate comparability across different panel assays, which may aid in broader adoption of panel assays and development of clinical applications.

MATERIALS AND METHODS

Twenty-nine tumor samples and 10 human-derived cell lines were processed and distributed to 16 laboratories; each used their own bioinformatics pipelines to calculate TMB and compare to whole exome results. Additionally, theoretical positive percent agreement (PPA) and negative percent agreement (NPA) of TMB were estimated. The impact of filtering pathogenic and germline variants on TMB estimates was assessed. Calibration curves specific to each panel assay were developed to facilitate translation of panel TMB values to whole exome sequencing (WES) TMB values.

RESULTS

Panel sizes >667 Kb are necessary to maintain adequate PPA and NPA for calling TMB high versus TMB low across the range of cut-offs used in practice. Failure to filter out pathogenic variants when estimating panel TMB resulted in overestimating TMB relative to WES for all assays. Filtering out potential germline variants at >0% population minor allele frequency resulted in the strongest correlation to WES TMB. Application of a calibration approach derived from The Cancer Genome Atlas data, tailored to each panel assay, reduced the spread of panel TMB values around the WES TMB as reflected in lower root mean squared error (RMSE) for 26/29 (90%) of the clinical samples.

CONCLUSIONS

Estimation of TMB varies across different panels, with panel size, gene content, and bioinformatics pipelines contributing to empirical variability. Statistical calibration can achieve more consistent results across panels and allows for comparison of TMB values across various panel assays. To promote reproducibility and comparability across assays, a software tool was developed and made publicly available.

West Nile Virus Vaccination Protects against Usutu Virus Disease in Mice

West Nile virus (WNV) and Usutu virus (USUV) are mosquito-borne flaviviruses that can cause neuroinvasive disease in humans. WNV and USUV circulate in both Africa and Europe and are closely related. Due to antigenic similarity, WNV-specific antibodies and USUV-specific antibodies have the potential to bind heterologous viruses; however, it is unclear whether this interaction may offer protection against infection. To investigate how prior WNV exposure would influence USUV infection, we used an attenuated WNV vaccine that contains the surface proteins of WNV in the backbone of a dengue virus 2 vaccine strain and protects against WNV disease. We hypothesized that vaccination with this attenuated WNV vaccine would protect against USUV infection. Neutralizing responses against WNV and USUV were measured in vitro using sera following vaccination. Sera from vaccinated CD-1 and Ifnar1^-/- mice cross-neutralized with WNV and USUV. All mice were then subsequently challenged with an African or European USUV strain. In CD-1 mice, there was no difference in USUV titers between vaccinated and mock-vaccinated mice. However, in the Ifnar1^-/- model, vaccinated mice had significantly higher survival rates and significantly lower USUV viremia compared to mock-vaccinated mice. Our results indicate that exposure to an attenuated form of WNV protects against severe USUV disease in mice and elicits a neutralizing response to both WNV and USUV. Future studies will investigate the immune mechanisms responsible for the protection against USUV infection induced by WNV vaccination, providing critical insight that will be essential for USUV and WNV vaccine development.

Rising utilization of coronary CT angiography across Europe over the last decade: insights from a large prospective European registry

Background/Introduction

The recently updated 2019 ESC guidelines for the diagnosis and management of chronic coronary syndromes endorse the use of coronary computed tomography angiography (CCTA) for exclusion of obstructive coronary artery disease in patients with a low clinical likelihood (Class I, LOE B). Higher demand for CCTA requires broad availability, inevitably involving smaller healthcare providers, such as non-academic hospitals and private practices. Nevertheless, most published data on CCTA image quality and safety rely on exams performed in high-volume academic centers, and little is known about CCTA in non-academic settings.

Purpose

To investigate the utilization of CCTA across Europe over the last decade, focusing on differences between academic and non-academic centers.

Methods

We included patients with stable chest pain and suspected coronary artery disease (CAD) who received CCTA and were included in the European Society of Cardiovascular Radiology MR/CT registry 01/2010–01/2020. We compared CT equipment, image quality, radiation dose, the incidence of periprocedural adverse events, patient characteristics, and CCTA findings between academic (high volume university hospitals) and non-academic centers (non-academic hospitals and private practices).

Results

Overall, 64,317 patients (41.2% women; age 60±13 years) from 212 sites across 19 European countries were included. Academic centers submitted most cases in 2010—2014 (51.6%), whereas non-academic centers accounted for 71.3% of records in 2015–2020. While non-academic centers used less advanced technology, radiation dose remained low (4.54 [interquartile range (IQR) 2.28–6.76] mSv) with a 30% decline of high-dose scans (&gt;7 mSv) over time. Diagnostic image quality was reported in 97.7% of cases, and the rate of acute scan-related events was low (0.4%) (Figure 1). From 2010–2014 to 2015–2020, CCTA nearly doubled in patients with low to intermediate pretest-probability, women &gt;50, and 40–60 years old men (Figure 2). CAD presence and extent decreased slightly over time (prevalence: 2010–2014: 41.5% vs. 2015–2020: 40.6%), (multi-vessel disease in those with CAD: 2010–2014: 61.9% vs. 2015–2020: 55.9%; all p&lt;0.01).

Conclusion

CCTA expands rapidly to non-academic centers across Europe, increasing availability while maintaining relatively low radiation dose, high diagnostic image quality, and safety. Broad availability of high-quality CCTA is essential for a successfully implementation of the recently updated guidelines for the diagnosis and management of chronic coronary syndromes.

Funding Acknowledgement

Type of funding sources: None. Changes in CCTA utilizationChanges in patient characteristics

The journey of tumor-infiltrating lymphocytes as a biomarker in breast cancer: clinical utility in an era of checkpoint inhibition

In 2014, we described a method to quantify percentage of tumor-infiltrating lymphocytes (TILs) on hematoxylin and eosin-stained slides of breast cancer samples using light microscopy that could be performed easily by pathologists with no extra stains. The aim of detailing the method was to facilitate independent research groups replicating our prognostic findings using TIL quantity in early-stage breast cancers. A global working group of breast pathologists was convened to standardize, test reproducibility, and refine the method. A website was also established which allowed free training (www.tilsinbreastcancer.org). As a result of this work, TIL data have been collected in over 20 000 primary breast cancer samples worldwide and the robust associations with better prognoses in triple-negative breast cancer (TNBC) and HER2+ BC have been confirmed. This has resulted in the inclusion of the TIL biomarker in several international breast cancer guidelines as well as in national criteria for routine pathology reporting. TIL therefore represents the first biological prognostic biomarker for early-stage TNBCs, and here its prognostic effect is linear, with values of 30%-50% being suggested as suitable for use in potential chemotherapy de-escalation studies. The efficacy of immune checkpoint-targeted agents in breast cancer now provides direct evidence that host immune responses can modify tumor growth in some patients. With the recent granting of accelerated approvals for the first PD-1/PD-L1 targeting agents in early and advanced TNBC, our focus has now moved to investigating the clinical utility of TIL in the setting of immune checkpoint agents, with or without PD-L1 protein assessment. Emerging data suggest that TIL quantity can help clinicians identify patients with breast cancer who benefit most from PD-1/PD-L1 inhibition. In patients with advanced TNBC and HER2+ disease a TIL cut-off of 5% or 10%, with PD-L1 expression can define 'immune-enriched' tumors and currently seems to have the most clinical relevance in this context.

Clinical recurrence of palpitations following slow pathway ablation in patients with suspected paroxysmal supraventricular tachycardias but non-documented, non-inducible tachycardias

Funding Acknowledgements

Type of funding sources: None.

Introduction

Catheter ablation is recommended as first-line treatment in patients with atrioventricular nodal reentry tachycardias (AVNRT). However, the best therapeutic modality in patients with dual AV nodal physiology but non-inducible tachycardias in electrophysiological study (EPS) remains controversial, especially when no tachycardias have been documented.

Our objective was to evaluate the results of empirical slow pathway ablation in patients showing dual AV nodal physiology but non-inducible AVNRT.

Methods

Multicenter, retrospective, observational registry of consecutive patients undergoing EPS due to clinical suspicion of paroxysmal supraventricular tachycardias (PSVT), but with no prior ECG documentation. Clinical, EPS and ablation (when performed) data were collected and andalyzed. 

Results

427 patients of 12 centers were included. Mean age was 46.3 ±16.1 and 297 (69.6%) were females. AVNRT was induced in 188 patients (typical in 181 cases, atypical in 7). Dual AV nodal physiology with or without single nodal echo beats, but with no sustained tachycardia and without evidence of accessory pathway was present in 68 patients. Ablation of the slow pathway was performed in 187/188 patients with AVNRT and in 30/68 patients with dual physiology. Among subjects with non-inducible tachycardia, ablation reduced significantly recurrences (39.5% in non-ablated vs. 16.7%; p = 0.04), with a level equivalent to those with ablated AVNRT(14.4% vs. 16.7%; p = 0.75). Procedure-related complications were similar in both groups: empirical ablation n = 1; 3.3% vs. induced tachycardia n = 6; 3.2% (p = 0.98).

Conclusions

In patients with high clinical suspicion of PSVT but non-documented and non-inducible arrhythmias, the presence of dual AV nodal physiology makes AVNRT a likely mechanism of the clinical tachycardia. Catheter ablation of slow pathway reduces the risk of recurrence to a level equivalent to those with inducible and ablated AVNRT. AVNRT (n = 188) Dual nodal physiology (n = 68) p value Age (years) 48.6 ± 16.3 41.9 ± 14.0 &lt;0.01 Female 71.8% 67.7% 0.52 Years symptomatic 9.3 ± 11.3 3.6 ± 8.1 &lt;0.01 Sudden onset 83.9% 88.0% 0.54 Abrupt end 73.4% 74.6% 0.96 Previous rate-slowing drugs 30.9% 25.0% 0.36 Previous antiarrhythmic drugs 5.9% 2.9% 0.35 Isoproterenol in EPS 70.0% 89.7% &lt;0.01

Recurrence of palpitations following electrophysiological study and ablation in suspected but undocumented paroxysmal supraventricular tachycardias: follow-up results of the BELIEVE-SVT registry

Funding Acknowledgements

Type of funding sources: None.

Introduction

ECG documentation of paroxysmal supraventricular tachycardias (PSVT) may be challenging due to their short duration and usually abrupt end.  As ablation represents first-line treatment of this pathologies, it is not uncommon that physicians refer patients to electrophysiological study (EPS) when symptoms are suggestive of PSVT even though no ECG documentation has been obtained. Our objective was to evaluate the results of ablation performed in patients with induced arrhythmias in EPS but no previous ECG documentation.

Methods

Retrospective and observational multicenter registry of consecutive patients undergoing EPS, followed or not by ablation, referred because of undocumented clinical suspicion of PSVT. We collected clinical, EPS and clinical follow-up data, along with data regarding ablation, when performed. Descriptive statistical analysis was carried out using Stata.

Results

427 patients of 12 centers were included. Mean age was 46.3 ± 16.1 and 297 (69.6%) were females. Sustained arrhythmias were induced in most patients (n = 255; 59.7%) and ablation was performed in 274 (64.2%). 10 complications (2.3% of procedures) were reported: 3 transient AV block, 2 PR interval prolongation, 2 puncture-related hematoma, 2 painful sites of puncture and 1 catheter entrapment in mitral chordae.

During a mean follow-up of 3.1 ± 2.0 years, 111 patients experienced recurrence of palpitations, mostly (n = 77; 69.4%) without ECG documentation. Clinical recurrence was more frequent in subjects who had not been ablated (41.8% vs 17.2% in ablated patients; risk ratio 2.44 (CI 95% 1.77-3.36); p &lt; 0.001). Table 1 shows types of clinical recurrences.

Conclusions

EPS in patients with high clinical suspicion of PSVT, followed by ablation when tachycardia is induced is effective in preventing future recurrences of palpitations. Early referral for EPS can, therefore, reduce visits to the emergency room, admissions and healthcare burden due to other low-yield, unnecessary tests. Type of recurrence ECG documentation 34(8.0%) ·Sinus rhythm 12(2.8%) ·Atrial tachycardia 6(1.4%) ·Typical atrioventricular nodal reentrant tachycardia 5(1.2%) ·Atrial fibrillation 5(1.2%) ·Premature ventricular beats 3(0.7%) ·Orthodromic atriventricular tachycardia 2(0.5%) Non documented recurrence 77(18.0%)

Frequency and patient attributes associated with ED visits within 30 days after discharge

Background

About 20%-25% of patients return to the emergency department (ED) within 30 days after inpatient discharge. This outcome is relevant since it may signal failures in inpatient care and care transitions. However, literature on the topic is still scarce. Our study aims to describe frequency and patient attributes associated with ED visits within 30 days (30d) of inpatient discharge in one public Portuguese hospital.

Methods

The study included adult patients discharged in 2016. Admissions of deceased or transferred patients were excluded. The rate of 30d ED visits after discharge was computed for selected patient (gender and age) and admission attributes [urgent, Major Diagnostic Category (MDC)]. Number of days from discharge to ED visit was determined. Logistic regression was used to compute crude and age-gender adjusted odds-ratios (cOR, aOR) for each selected admission attribute.

Results

From the 21744 admissions included (median age: 58y; 40% male), for 5058 there was at least one ED visit within 30d after discharge (23%). The majority of ED visits were triaged urgent (n = 2286; 45%) or very urgent (n = 1499; 30%). Time to first ED visit was, on average, 11 days. The risk of ED visit was increased among men (cOR = 1.180; 95% confidence interval - 95%CI: 1.103-1.262) and patients aged 75 or older (cOR = 1.704; 95%CI: 1.557-1.866). After controlling for gender and age differences, admissions with mental diseases (aOR = 1.807; 95%CI: 1.452-2.247), respiratory diseases (aOR = 1.786; 95%CI: 1.535-2.078), endocrine diseases (aOR = 1.758; 95%CI: 1.374-2.250) showed increased risk of visiting ED after discharge.

Conclusions

ED visits after inpatient discharge are frequent and mostly due to urgent and very urgent needs. Older age, mental, respiratory and endocrine conditions are relevant patient risk factors for returning hospital for ED care shortly after discharge.

Key messages

Improved quality of inpatient care and care transitions that reduce ED visits after discharge may benefit a significant part of patients. Future initiatives to reduce adverse events after discharge may target patients with older age or with mental conditions.

Prognostic value of tumor-infiltrating lymphocytes in patients with early-stage triple-negative breast cancers (TNBC) who did not receive adjuvant chemotherapy

BACKGROUND

Although stromal tumor-infiltrating lymphocytes (sTILs) have been considered an important prognostic factor in early-stage triple-negative breast cancer (TNBC), there have been limited data on their prognostic value in the absence of adjuvant chemotherapy.

PATIENTS AND METHODS

A pooled analysis was carried out using four cohorts of TNBC patients not treated with chemotherapy. sTILs were evaluated in the most representative tumoral block of surgical specimens. Cox proportional hazards regression models were used for invasive disease-free survival (iDFS), distant disease-free survival (D-DFS), and overall survival (OS), fitting sTILs as a continuous variable adjusted for clinicopathologic factors.

RESULTS

We analyzed individual data of 476 patients from 4 centers diagnosed between 1989 and 2015. Their median age was 64 years. The median tumor size was 1.6 cm and 83% were node-negative. The median level of sTILs was 10% (Q1-Q3, 4%-30%). Higher grade was associated with higher sTILs (P < 10-3). During follow-up, 107 deaths, and 173 and 118 events for iDFS and D-DFS were observed, respectively. In the multivariable analysis, sTILs obtained an independent prognostic value for all end points (likelihood ratio χ2 = 7.14 for iDFS; P < 10-2; χ2 = 9.63 for D-DFS, P < 10-2; χ2 = 5.96 for OS, P = 0.015). Each 10% increment in sTILs corresponded to a hazard ratio of 0.90 [95% confidence interval (CI) 0.82 - 0.97] for iDFS, 0.86 (95% CI 0.77 - 0.95) for D-DFS, and 0.88 (95% CI 0.79 - 0.98) for OS, respectively. In patients with pathological stage I tumors with sTILs ≥30% (n = 74), 5-year iDFS was 91% (95% CI 84% to 96%), D-DFS was 97% (95% CI 93% to 100%), and OS was 98% (95% CI 95% to 100%).

CONCLUSION

sTILs add important prognostic information in systemically untreated early-stage TNBC patients. Notably, sTILs can identify a subset of stage I TNBC patients with an excellent prognosis without adjuvant chemotherapy.

Human Polyclonal Antibodies Prevent Lethal Zika Virus Infection in Mice

Zika virus (ZIKV) is an emerging mosquito-borne flavivirus that represents a major threat to global health. ZIKV infections in adults are generally asymptomatic or present with mild symptoms. However, recent outbreaks of ZIKV have revealed that it can cause Congenital Zika Syndrome in neonates and Guillain-Barré syndrome in adults. Currently, no ZIKV-specific vaccines or antiviral treatments are available. In this study, we tested the efficacy of convalescent plasma IgG hyperimmune product (ZIKV-IG) isolated from individuals with high neutralizing anti-ZIKV titers as a therapeutic candidate against ZIKV infection using a model of ZIKV infection in Ifnar1^-/- mice. ZIKV-IG successfully protected mice from lethal ZIKV challenge. In particular, ZIKV-IG treatment at 24 hours after lethal ZIKV infection improved survival by reducing weight loss and tissue viral burden and improving clinical score. Additionally, ZIKV-IG eliminated ZIKV-induced tissue damage and inflammation in the brain and liver. These results indicate that ZIKV-IG is efficacious against ZIKV, suggesting this human polyclonal antibody is a viable candidate for further development as a treatment against human ZIKV infection.

Abstract PD5-10: Immune characterization of matched primary and multiple metastatic samples issued from an institutional autopsy cohort

Introduction

While immune infiltrates have already been extensively characterized in primary tumors (P), data on breast cancer metastases (M) remains limited. To this end we quantified and qualified the immune cells in a unique cohort of multiple matched P and M samples selected from an institutional breast cancer autopsy cohort.

Patients and methods

Twenty-three patients were selected from an institutional autopsy program (Semmelweis University, Budapest, Hungary) based on matched P and M sample availability (124 samples). All samples were centrally characterized for estrogen (ER), progesterone (PR) and HER2 receptors. The primary molecular subtypes were as follows: 9 ER+/PR+/HER2-, 8 triple negative and 6 HER2+. Ten patients relapsed ≤1 year after diagnosis and were further referred to as “early relapsers”, as opposed to the remaining qualified as “late relapsers”. Immunohistochemistry (IHC) was carried out against CD3/CD20 and CD4/CD8 in 21 patients (119 samples). Tumor infiltrating lymphocytes (TILs) were assessed on hematoxylin and eosin (H&E) and CD3-stained slides. Gene expression data were generated using the NanoString nCounter assay (PanCancer Immune Profiling Panel) for 11 patients (35 samples) and analyzedusing the R package NanoStringQCPro. The scores from published immune gene signatures were calculated as a weighted sum of the expressions of their genes. All samples were analyzed for 22 immune cell subtypes relative abundance using CIBERSORT.

Results

TILs assessed on H&E and CD3-stained slides were weakly correlated (Rho= 0.38, p&lt;.001). TIL levels as well as the number of tertiary lymphoid structures (TLS) were significantly lower in Ms as compared to Ps (p&lt;.001). Among the different metastatic sites, the lung was more infiltrated when considering CD3+ and CD4+ cells (p=.01 and .02, respectively). We further observed significantly higher levels of TILs, CD3+, CD4+ and CD8+ cells in the Ms but not in the Ps from late relapsers as opposed to those from early relapsers. Gene expression analyses further confirmed these observations as several immune gene signatures displayed significantly higher scores in the Ms from late compared to early relapsers. An unsupervised analysis identified 13 genes significantly differentially expressed between Ps and Ms: CSF1R, CXCL14, CYBB, IL21R, IL2RB, TNF and TNFSF15 were upregulated in Ps while BCL2L1, C7, HSD11B1, and PSMB7 were upregulated in Ms. The matched P/M CIBERSORT analyses revealed a distinct composition of immune cell types between P and M of a same patient. Apart from a potential increase in M0 macrophages, no common trait was observed in immune cell composition between the Ms from the different patients.

Conclusion

This is to the best of our knowledge the first study characterizing the immune infiltration in patients with multiple matched P and M samples. The results suggest that Ms have not only a globally lower immune infiltration as compared to Ps, but also a different immune composition. Additionally, Ms from late relapsers are more infiltrated as compared to early relapsers. The present data also uncovers not only important inter-patient but also intra-patient immune heterogeneity, which should be taken into consideration for optimal treatment decision.

Citation Format: Szekely B, Bareche Y, Van den Eynden G, Salgado R, Buisseret L, Garaud S, Willard-Gallo K, Hatzis C, Szasz M, Kulka J, Larsimont D, Sotiriou C, Pusztai L, Desmedt C. Immune characterization of matched primary and multiple metastatic samples issued from an institutional autopsy cohort [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD5-10.

Abstract PD5-06: The immunomodulatory potential of denosumab in breast cancer: results from D-BEYOND, a window of opportunity trial evaluating a RANK-ligand (RANKL) inhibitor and its biological effects in young pre-menopausal women diagnosed with early breast cancer

Background

Breast cancer (BC) in young women has unique biology and poor prognosis. Previous reports suggest that they often express RANKL, which was also shown to play a role in mammary tumorigenesis and various immune processes. Here, we present the primary results of D-BEYOND, a window study investigating the biological activity of the RANKL inhibitor; denosumab in pre-menopausal BC patients.

Methods

D-BEYOND is a prospective, phase Iia, single-arm, multicenter study assessing the effect of denosumab on BC biology in premenopausal women with early BC (NCT01864798). Patients received two subcutaneous injections of denosumab (120mg), one week apart, followed by breast surgery. The primary endpoint was geometric mean change in tumor Ki67 assessed by immunohistochemistry (IHC). Blood, tumor and normal adjacent breast tissue were collected pre- and post-treatment. Serum levels of RANKL, OPG and CTX were assessed by ELISA. RNA was extracted from fresh-frozen tissue and RNAseq was performed. DESeq2 was used for differential expression analysis, GAGE was used for pathway analysis and CIBERSORT was used to infer immune cell subsets between pre- and post-treatment. Ki67, CD4/Foxp3 and CD4/CD8 IHC were performed on FFPE tissue to further assess the immune microenvironment. The percentage of TILs was independently evaluated by two pathologists on H&E slides. Pre- and post-treatment values were compared using a paired t-test.

Results

A total of 27 patients were enrolled in the study between October 2013 and July 2016. The median age was 45 years (range 35-51 years). Tumors of 21 patients were hormone receptor positive (77.8%), 4 were HER2 positive (14.8%) and 2 were triple negative (7.4%). No serious adverse events were reported, the most frequent non-serious adverse event being arthralgia (14.8%). After treatment, serum levels of CTX and RANKL decreased in all patients (P &lt; 0.001) whereas OPG increased in 76.9% of patients (P = 0.009, 95% CI 0.56-0.91). There was no significant reduction of Ki67 values from baseline (geometric mean [GM] change after treatment; 0.98, 95% CI 0.76-1.26; P = 0.90). Twenty-four pre- and post-treatment tumor pairs were available for RNAseq, IHC and TILs evaluation. There was a significant increase in the percentage of stromal TILs after treatment (GM change of 1.75, 95% CI 1.28–2.39; P = 0.001). 1084 differentially expressed genes were identified and pathway analysis revealed enrichment of several immune processes. CIBERSORT revealed an enrichment of CD8+ T cells (GM change 1.72, 95% CI 1.19–2.48; P = 0.006) and a decrease of Treg cells (0.71, 95% CI 0.52–0.98, P = 0.040). These results were confirmed by IHC of CD8+ and CD4+/Foxp3+ cells (GM change 1.59, 95% CI 1.14–2.21; P = 0.008 and 0.63, 95% CI 0.49–0.83, P = 0.001, respectively).

Conclusion

Short course of denosumab did not reduce tumor proliferation rate. However, it induced a significant increase in TILs and CD8 cytotoxic T cells, while Treg infiltration decreased. These findings suggest an immunomodulatory role for denosumab in young breast cancer and that its use in combination could boost immunotherapy efficacy.

Citation Format: Nguyen B, Marion M, Salgado R, Venet D, Vuylsteke P, Polastro L, Wieldiers H, Simon P, Lindeman G, Larsimont D, Van den Eynden G, Velghe C, Rothe F, Garaud S, Michiels S, Willard-Gallo K, Azim Jr HA, Loi S, Piccart M, Sotiriou C. The immunomodulatory potential of denosumab in breast cancer: results from D-BEYOND, a window of opportunity trial evaluating a RANK-ligand (RANKL) inhibitor and its biological effects in young pre-menopausal women diagnosed with early breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD5-06.

Abstract PD5-03: Characterization of high TIL breast cancers reveals a prognostic and functionally distinct tissue-resident memory subpopulation

Background: Tumor infiltrating lymphocytes (TILs) assessed via light microscopy are prognostic and predictive in the early stage and advanced triple negative and HER2-amplified breast cancer (BC). Higher TILs can also identify patients more likely to benefit from anti-PD-1 therapy. In this study we interrogated T cell subsets that comprise high TILs to determine if distinct subpopulations are key mediators of anti-tumor immunity.

Methods: We characterised TILs with a focus on CD3+ T cells in 129 primary and metastatic BC samples using flow cytometry, bulk RNASeq on flow sorted T cell populations, multiplex immunohistochemistry and microdroplet based single cell 3' mRNA sequencing on the 10X Genomics Chromium platform. Cell type specific gene expression signatures were determined from differential expression between putative T cell subpopulations. These signatures were investigated in clinical cohorts, including trial cohorts treated with pembrolizumab.

Results: High TIL Infiltrates consisted primarily of CD3+ T cells, with both CD8 and CD4 populations. Unsupervised clustering of single cell sequencing identified 9 CD8 and CD4 subpopulations with distinct gene expression profiles. In addition to Tregs and CD8 effector memory (TEM) T cells, we found a CD8+ tissue resident memory (TRM) population expressing greater levels of T-cell checkpoints and cytotoxic markers compared to effector memory cells. In 2 primary tumours and 1 liver metastasis, bulk RNASeq of flow sorted TEM and TRM corroborated the single cell mRNASeq results. T cell receptor profiling (TCR) in the 3 samples found non-overlapping repertoires in the 2 primary tumours, but overlap in one metastatic lesion, suggesting divergent developmental origins in the breast, but the potential for nascent TRM differentiation in a metastatic niche. Clustering of these TCRs suggested differing antigen specificities between TRM and non-TRM CD8 T cells. Using Metabric data, the CD8 TRM gene expression signature was prognostic for disease free survival (DFS) in primary TNBCs (n=329, log-rank p=0.003), and was able to further stratify cases with high and low CD8A expression for DFS (log-rank p = 0.03). The CD8 TRM signature was enriched in baseline tumour samples of responders (n = 9) compared with non-responders (n=36) in 45 patients with metastatic melanoma treated with T cell checkpoint blockade (p &lt; 0.0001). Additional single cell sequencing data with TCR sequencing will be combined with these initial results, and an independent data set of single cell mRNASeq and TCR Seq on CD3+ BC TILs will be used to confirm our findings. Cell type specific signatures will be explored in additional clinical cohorts including KEYNOTE-086, and presented at the meeting.

Conclusion: Using single cell profiling of the immune microenvironment in BC we demonstrate that high TIL BCs contain multiple T cell subpopulations with different functional and prognostic significance. Our approach identified a CD8 TRM population with a distinct gene expression profile and strong expression of key immune checkpoints likely representing the presence of true tumor specific immunity. This population may be a key target of immune checkpoint blockade.

Citation Format: Savas P, Virassamy B, Ye C, Salim A, Mintoff CP, Caramia F, Salgado R, Teo ZL, Dushyanthen S, Byrne A, Luen SJ, Fox SB, Speed TP, Mackay LK, Neeson PJ, Loi S. Characterization of high TIL breast cancers reveals a prognostic and functionally distinct tissue-resident memory subpopulation [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD5-03.

Abstract P3-10-09: Relationship between tumor infiltrating lymphocytes (TILs) and response to pembrolizumab (Pembro)+chemotherapy (Chemo) as neoadjuvant treatment (NAT) for triple-negative breast cancer (TNBC): phase Ib KEYNOTE-173 trial

Background:Increasing quantities of stromal TILs (sTILs) are associated with higher pathologic complete response (pCR) rates with conventional chemo in early-stage TNBC. We evaluated the association between sTILs and PD-L1 expression with response to pembro+chemo as NAT for TNBC in the KEYNOTE-173 trial (NCT02622074).

Methods: sTILs were quantified using light microscopy of H&E-stained slides from pretreatment and on-treatment (during first 3 weeks of pembro monotherapy) tumor biopsies by a pathologist blind to response data. Pretreatment PD-L1 expression was assessed using the PD-L1 IHC 22C3 pharmDx assay and reported as combined positive score (CPS). Endpoints were pCR rate by ypT0 ypN0 and ypT0/Tis ypN0 and objective response rate (ORR; RECIST v1.1) after the first 4 cycles of NAT (taxane±carboplatin+pembro) by MRI. sTILs and PD-L1 CPS were evaluated as continuous variables. Association between sTILs and PD-L1 CPS with response was assessed using logistic regression and area under the reciever operating curve (AUROC) analyses, with a 1-sided alpha level of 0.10. Correlation between PD-L1 and sTILs was assessed by Spearman's rank correlation coefficient. Multivariate analysis included sTILs (pretreatment and on-treatment) and PD-L1 CPS. Likelihood ratio tests were used to evaluate the added value of factors in predicting pCR rate.

Results: Of 60 total pts, 34 had tumors evaluated for pretreatment sTILs, 52 for PD-L1 CPS, and 33 for both sTILs and CPS. On-treatment sTILs were evaluated in 31 pts. Overall pCR rates were 56.7% and 60% by ypT0 ypN0 and ypT0/Tis ypN0, respectively; ORR was 78.3%. In pts evaluated for sTILs and CPS (individually), pCR rates and ORR were comparable with overall pCR rates and ORR. There was a significant correlation between pretreatment sTILs and PD-L1 CPS (ρ=0.65, P&lt;0.001).Higher pretreatment sTILs were significantly associated with response: ypT0 ypN0 P= 0.011; ypT0/Tis ypN0 P=0.006; ORR P=0.061. On-treatment sTILs were also significantly associated with response: ypT0 ypN0 P=0.061; ypT0/Tis ypN0 P=0.041; ORR P=0.031. Pretreatment PD-L1 CPS was significantly associated with response: ypT0 ypN0 P=0.073; ypT0/is ypN0 P=0.030; and ORR P=0.021. AUROC of pretreatment sTIL association with pCR was numerically higher than with on-treatment sTILs and PD-L1 CPS (0.69 vs 0.61 vs 0.56 for ypT0ypN0 and 0.72 vs 0.67 vs 0.62 for ypT0/Tis ypN0). Responders had higher median pretreatment sTIL levels vs nonresponders: 45% [10, 75] vs 10% [5, 20] for pCR rate by ypT0 ypN0 and 52.5% [10, 73.8] vs 10% [5, 20] for pCR rate by ypT0/Tis ypN0; 25% [5, 70] vs 10% [6.3, 27.5] for ORR. In multivariate analysis, only pretreatment sTILs were significant for both pCR endpoints (ypT0 ypN0 P=0.031; ypT0/Tis ypN0 P=0.034). Likelihood ratio tests demonstrated that for both pCR endpoints, PD-L1 CPS (P=0.683/P=0.422) and on-treatment sTILs (P=0.984/P=0.568) did not add significantly more value to pretreatment sTILs when predicting pCR.

Conclusions:Higher quantities of pretreatment sTILs and PD-L1 CPS and on-treatment sTILs were significantly associated with higher pCR rates and ORR in primary TNBC treated with pembro and NAT.

Citation Format: Loi S, Schmid P, Cortés J, Park YH, Muñoz-Couselo E, Kim S-B, Sohn J, Im S-A, Holgado E, Foukakis T, Kuemmel S, Dent R, Wang A, Aktan G, Karantza V, Salgado R. Relationship between tumor infiltrating lymphocytes (TILs) and response to pembrolizumab (Pembro)+chemotherapy (Chemo) as neoadjuvant treatment (NAT) for triple-negative breast cancer (TNBC): phase Ib KEYNOTE-173 trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-10-09.

Prognostic implications of residual disease tumor-infiltrating lymphocytes and residual cancer burden in triple-negative breast cancer patients after neoadjuvant chemotherapy

BACKGROUND

For primary triple-negative breast cancer (TNBC) treated with neoadjuvant chemotherapy (NAC), higher pretreatment tumor-infiltrating lymphocytes (TILs) correlates with increased pathologic complete response (pCR) rates, and improved survival. We evaluated the added prognostic value of residual disease (RD) TILs to residual cancer burden (RCB) in predicting survival post-NAC.

PATIENTS AND METHODS

We combined four TNBC NAC patient cohorts who did not achieve pCR. RD TILs were investigated for associations with recurrence-free survival (RFS), and overall survival (OS) using Cox models with stromal TILs as a continuous variable (per 10% increment). The likelihood ratio test was used to evaluate added prognostic value of RD TILs.

RESULTS

A total of 375 RD TNBC samples were evaluable for TILs and RCB. The median age was 50 years, with 62% receiving anthracycline/taxane chemotherapy. The RCB class after NAC was 11%, 50%, and 39% for I, II, and III, respectively. The median RD TIL level was 20% (IQR 10-40). There was a positive correlation between RD TIL levels and CD8+ T-cell density (ρ = 0.41). TIL levels were significantly lower with increasing post-NAC tumor (P = 0.005), nodal stage (P = 0.032), but did not differ by RCB class (P = 0.84). Higher RD TILs were significantly associated with improved RFS (HR: 0.86; 95% CI 0.79-0.92; P < 0.001), and improved OS (HR: 0.87; 95% CI 0.80-0.94; P < 0.001), and remained significant predictors in multivariate analysis (RFS P = 0.032; OS P = 0.038 for OS). RD TILs added significant prognostic value to multivariate models including RCB class (P < 0.001 for RFS; P = 0.021 for OS). The positive prognostic effect of RD TILs significantly differed by RCB class for RFS (PInt=0.003) and OS (PInt=0.008) with a greater magnitude of positive effect observed for RCB class II than class III.

CONCLUSIONS

TIL levels in TNBC RD are significantly associated with improved RFS and OS and add further prognostic information to RCB class, particularly in RCB class II.

72 Effect of incubation temperature and of CO2 concentration during early cleavage on equine in vitro embryo production

Intracytoplasmic sperm injection (ICSI) is currently being used for equine in vitro embryo production for both research and clinical purposes. However, some basic parameters for in vitro embryo production, such as the optimum incubator temperature and the optimum CO2 concentration/pH of medium for early embryo development, have not yet been established in the horse. The incubation temperature used by many laboratories for equine in vitro embryo production is 38.2°C, whereas the range of normal rectal temperature in the horse is 37.2 to 38.3°C. In Exp. 1, we evaluated maturation, cleavage, and blastocyst rates under 3 different culture temperatures. Cumulus-oocyte complexes were recovered from slaughterhouse-derived ovaries and shipped overnight at room temperature. Oocyte maturation was performed concurrently in separate incubators set to 37.2, 37.7, or 38.2°C. Mature oocytes were subjected to ICSI, then cultured in mixed gas (6% CO2, 5% O2, and remainder N2) at the same temperature at which they were matured. Embryo culture media used were a commercial human medium (global) for Days 0 to 5, then DMEM/F-12 from Day 5 to 10, both with 10% fetal bovine serum (FBS). In Exp. 2, we evaluated 3 different CO2 concentrations (6, 6.5, or 7% CO2) in mixed gas for the Day 0 to 5 culture in global+FBS, at 38.2°C. Cumulus-oocyte complexes were recovered from live mares by transvaginal aspiration and held overnight at room temperature; all other parameters remained the same as for Exp. 1. Data were analysed by Fisher’s exact test. In Exp. 1, a total of 280 oocytes were utilised; the outcomes for the 37.2, 37.7, and 38.2°C treatments were, respectively: maturation rates of 33, 38, and 42%; cleavage rates of 84, 86, and 88%; and blastocyst rates per injected oocyte of 35, 44, and 44%. There were no significant differences among the 3 temperature treatments for any parameter (P&gt;0.2). In Exp. 2, the pH of the global+FBS medium was 7.38, 7.35, and 7.3 for 6, 6.5, and 7% CO2, respectively. A total of 106 mature oocytes underwent ICSI; the outcomes for the 3 CO2 atmospheres, respectively, were cleavage rates of 68, 80, and 70% and blastocyst rates per injected oocyte of 42, 54, and 27%. The blastocyst rate for the 7% CO2 treatment was significantly lower than that for the 6.5% CO2 treatment (P&lt;0.05). These results indicate that equine in vitro embryo production is equally effective throughout the range of normal equine body temperature, and that equine blastocyst production is sensitive to small changes in CO2 atmosphere/pH of medium during early cleavage-stage development. Research was supported by the Clinical Equine ICSI Program, Texas A&amp;M University, the Link Equine Research Endowment, Texas A&amp;M University, and Fonds en Santé Équine (FSÉ), Faculté de Médecine Vétérinaire, and Université de Montréal.

[Design of a thromboprophylaxis care process in patients with atrial fibrillation]

OBJECTIVE

To describe the milestones in the anticoagulant care process of atrial fibrillation patients (AF), as well as quality and safety indicators, in order to establish an integrated care process of these patients in the Community of Madrid.

METHODS

A consensus conference technique was applied, with the participation of 21 professionals (seven in the Steering Group and 14 known experts), from the specialties of Emergency, Internal Medicine, Cardiology, Neurology, Haematology, Family Medicine, Nursing, and Quality. Hospitals and Primary Care were represented. Milestones, elements and barriers/limitations were agreed upon in the care process of anticoagulated AF patients. A minimum set of indicators were also defined to assess the quality of care.

RESULTS

Four milestones (stratification of thromboembolism and bleeding risk, evaluation for anticoagulant treatment, follow-up of direct-acting oral anticoagulants, and follow-up of treatment with vitamin K antagonists) were identified. A total of 14 barriers/limitations were also prioritised. In total, six indicators were defined (two structural-related, two processes-related, and two outcomes-related).

CONCLUSIONS

Milestones and critical activities, together with a set of indicators, have been agreed for the development of guidelines with which to achieve a better therapeutic approach for anticoagulated AF patients.

Abstract PD6-05: Distinct tumor microenvironments stratify triple negative breast cancer into immune subtypes

Background:

Triple negative breast cancer (TNBC) are especially difficult to treat effectively. While only 20-30% of TNBC patients respond to chemotherapy in the neoadjuvant setting, overall outcome remains poor for non-responding patients. Engaging the immune system promises optimal personalized cancer therapy as mounting evidence suggests that immune-checkpoint inhibitor immunotherapies may become a therapeutic option for TNBC patients. The presence of CD8+ T cells, a crucial component of the cytotoxic arm of the adaptive immune response, is associated with good clinical outcome in TNBC patients. Specifically, it is the efficient CD8+ T cell invasion and infiltration in the tumor that is associated with good outcome. On the other hand, some tumors accumulate CD8+ T cells in the tumor-associated stroma with poor infiltration in the tumor epithelium. These patients show poor outcome. As CD8+ T cell infiltration in the tumor is a crucial step to mount an efficient anti-tumor response, we thus wondered how the tumor microenvironment affects CD8+ T cell invasion into the tumor epithelial compartment of the TNBC tumors.

Methods:

To identify potential stroma-dependent mechanisms that potentiate or inhibit CD8+ T cells invasion into the tumor epithelium, we coupled analysis of spatial patterns of CD8+ T cell localization by Immunohistochemistry (IHC) andperformed gene expression profiling of laser-capture microdissected tumor-associated stroma (as well as matched epithelium and bulk tumor) from 38 TNBC chemotherapy-naive primary cases. GSEA-based Metasignatures were derived from bulk tumor gene expression data from our cohort. To investigate the compartment of origin of the pathways identified via the Metasignatures, the (LCM)-derived tumor stromal and epithelial gene expression were analyzed.

Results:

CD8+ T cell quantification in different compartments of the tumor identify 3 main subgroups of TNBC based on CD8+ T cell localization. Importantly we developed a 2-step classification scheme based on CD8+ T cell localization. We developed metasignatures following our 2 steps classification and identified key bulk tumor metasignatures that showed prognostic value in an independent cohort. In addition the matched LCM gene expression from the tumor epithelium and stromal compartments allowed us to identify the compartment of origin.

Importantly, while 1 group of TNBC tumor was showing a significant anti-tumor response, the 2 other groups showed absence of such environment. The 2 non inflamed immune subtypes showed distinct phenotypes and biologies associated with poor anti-tumor response that we validated by immunohistochemistry and fluorescence. These results highlight different potential mecanisms that lead to immune evasion and allow us to stratify TNBC into immune subgroups.

Citation Format: Gruosso T, Gigoux M, Bertos N, Manem VS, Zuo D, Saleg SM, Souleimanova M, Zhao H, Johnson RM, Monette A, Muñoz Ramos V, Hallett MT, Stagg J, Lapointe R, Omeroglu A, Meterissian S, Buisseret L, Van den Eyden G, Salgado R, Guiot M-C, Haibe-Kains B, Park M. Distinct tumor microenvironments stratify triple negative breast cancer into immune subtypes [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD6-05.

Abstract P1-08-02: Breast tumor-specific MHC-II expression drives a unique pattern of adaptive resistance to antitumor immunity through MHC-II receptor checkpoint engagement

Background: We have previously shown that some breast cancers express major histocompatibility complex II (MHC-II), correlating with enhanced immune infiltration. In other tumor types, we have shown that MHC-II expression on tumor cells predicts clinical response to checkpoint inhibition. We sought to determine the direct effects of MHC-II on anti-tumor immunity and characterize mechanisms of immune escape in this breast cancer subset.

Methods: To determine the functional effects of MHC-II on tumor cells, we generated isogenic mouse breast tumor cells with enforced MHC-II expression and determined their ability to generate tumors in syngeneic mice, the impact on immunity, and their response to checkpoint inhibition. In a series of molecularly-characterized HER2+ (n=8) and triple-negative breast cancers (TNBC; n=103), we performed immunohistochemistry (IHC) and quantitative immunofluorescence (QIF) for Lag-3, PD-L1, CD4, CD8, FCRL6, and granzyme B.

Results: Following injection in syngeneic immunocompetent mice, MHC-II+ mouse breast tumors were more frequently rejected (p=0.04) and recruited greater numbers of CD4+ TILs. When MHC-II+ tumors escaped rejection, they expressed higher degrees of PD-1 and Lag-3 in the tumor and in the draining lymph node. Since Lag-3 is a checkpoint that specifically targets MHC-II, we hypothesized that MHC-II+ breast cancers escape anti-tumor immunity through suppressing MHC-II-mediated antigen presentation. Combinations of anti-Lag-3 and anti-Pd-1 antibodies inhibited growth of MHC-II+ tumors. These findings led us to also explore Fc receptor-like 6 (FCRL6), a previously reported MHC-II receptor expressed on NK and cytotoxic T cells. Residual MHC-II+ TNBC post-neoadjuvant chemotherapy (NAC) recruited greater numbers of CD4+ and CD8+ TILs (p=0.0001 and p=0.0002), suggesting enhanced immune recognition. However, MHC-II+ TNBCs also demonstrated a greater frequency of Lag-3+ and FCRL6+ TILs (p&lt;0.001 and p=0.01, respectively) which frequently co-occurred (p=0.003). Thus, our data suggest that MHC-II expression in breast tumors supports recruitment of MHC-II-specific checkpoint-positive TILs. In line with this concept, QIF analysis demonstrated that the presence of Lag3+ and/or FCRL6+ TILs was strongly associated with suppression of T cell cytotoxicity as assessed by granzyme-B+ CD8+ T cells (p=0.0001 and p=0.002, respectively). Functional analyses of FCRL6 on human NK cell lines and peripheral blood mononuclear cells (PBMCs) demonstrated that like Lag3, FCRL6 is a checkpoint which engages MHC-II and suppresses cytotoxic NK and T cell activity.

Conclusions: These data suggest that MHC-II+ breast tumors are immunologically active and circumvent anti-tumor immunity by targeting MHC-II antigen presentation through recruitment of Lag-3+ and FCRL6+ TILs. We describe herein FCRL6 as a novel bona fide immune checkpoint which targets MHC-II, which may impact a variety of cancers. MHC-II expression status may be a useful biomarker for patient stratification on anti-PD-1/anti-Lag-3 combination, and eventually, anti-PD-1/anti-FCRL6 combinations in patients with breast cancer.

Citation Format: Balko JM, Johnson DB, Ericsson-Gonzalez P, Nixon MJ, Salgado R, Sanchez V, Shreeder DM, Rimm DL, Loi S, Kim JY, Bordeaux J, Sanders ME, Davis RS. Breast tumor-specific MHC-II expression drives a unique pattern of adaptive resistance to antitumor immunity through MHC-II receptor checkpoint engagement [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-08-02.

Abstract P2-03-01: Analytical validation of a standardized scoring protocol for Ki67 assessed on breast excision whole sections: An international multicenter collaboration

Aims: (i) Determine whether between-observer reproducibility for Ki67 when assessed on whole sections according to a standardized scoring protocol is adequate for clinical application. (ii) Compare between-observer reproducibility of Ki67 scores assessed on hot-spots to scores using a global method that averages across a tissue section.

Background: The nuclear proliferation biomarker Ki67 has multiple potential roles in breast cancer, including aiding decisions based on prognosis, but unacceptable levels of between-laboratory variability have been observed. The International Ki67 in Breast Cancer Working Group has undertaken a systematic program to determine whether Ki67 measurement can be analytically validated and standardized across labs. In phase 1, variability in visual interpretation was identified as an important source of variability. Phases 2 and 3a showed that adherence to defined scoring methods substantially improved reproducibility in scoring tissue microarrays and core-cut biopsies. We now assess whether acceptable reproducibility can be achieved on whole sections.

Methods: Adjacent sections from 30 primary ER+ breast cancers were centrally stained for Ki67 to assemble 4 sets of 30 stained tumor sections, circulated around 23 labs in 12 countries. Ki67 was scored by 2 methods by all labs: (a) global: 4 fields of 100 tumor cells each were selected to reflect observed heterogeneity in nuclear staining (b) hot-spot: the field with highest Ki67 percentage of tumor cells with nuclear staining was selected and up to 500 cells scored. Ki67 scores were log2-transformed for statistical analyses and back-transformed for presentation. The primary objective was to assess whether either method could achieve an intraclass correlation coefficient (ICC) significantly greater than 0.8, considered substantial to almost-perfect reproducibility. Secondary objectives were to assess which method had highest observed ICC and to assess whether observers identified the same “hot-spots”.

Results: ICC for the global method was 0.87 (95%CI: 0.799-0.93), marginally meeting the prespecified success criterion. The ICC for the hot-spot method was 0.83 (95%CI: 0.74-0.90) and had a CI extending below the success criterion. Across the 23 labs, geometric mean value of the 30 scores ranged from 8.5 to 19.6 for the global method and from 12.8 to 30.3 for the hot-spot method. The overall mean (95% CI) of these values was 12.9 (11.9-14.0) and 20.9 (19.1-22.8), respectively. Visually, between-laboratory agreement in location of selected hot-spot varies between cases. The median times for scoring were 9 and 6 minutes for global and hot-spot methods respectively.

Conclusions: The global method marginally met the prespecified criterion of success; it should now be evaluated for clinical validity in appropriate cohorts of cases. The hot-spot method was observed to have slightly less reproducibility between labs. The time taken for scoring by either method is practical using counting software we are making publicly available. Establishment of external quality assessment schemes is likely to improve the reproducibility between labs further.

(Supported by a grant from the Breast Cancer Research Foundation)

Citation Format: Nielsen TO, Leung SCY, Zabaglo LA, Arun I, Badve SS, Bane AL, Bartlet JMS, Borgquist S, Chang MC, Dodson A, Ehinger A, Fineberg S, Focke CM, Gao D, Gown AM, Gutierrez C, Hugh JC, Kos Z, Lænkholm A-V, Mastropasqua MG, Moriya T, Nofech-Mozes S, Osborne CK, Penault-Llorca FM, Piper T, Sakatani T, Salgado R, Starczynski J, Sugie T, van der Vegt B, Viale G, Hayes DF, McShane LM, Dowsett M. Analytical validation of a standardized scoring protocol for Ki67 assessed on breast excision whole sections: An international multicenter collaboration [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-03-01.

Abstract P2-05-04: Deregulation of A-to-I RNA editing is associated with poor prognosis in HER2+ breast cancers in the neoALTTO trial

Background

A-to-I RNA editing, a post-transcriptional modification of the RNA catalyzed by the ADAR family of enzymes, is emerging as a widespread phenomenon in breast cancer (BC). A-to-I RNA editing is more frequent in the highly repetitive Alu regions but can affect both coding and non-coding regions. It has been shown to greatly impact cell functionality. In a recent report, we have shown that A-to-I RNA editing is regulated both by ADAR copy number and type I interferon response (Fumagalli et al. Cell Rep 2015). The main aim of the current study was to investigate the extent and profile of A-to-I RNA editing in HER2+ BC patients (pts) treated in the NeoALTTO trial, and to explore its impact on pathologic complete response (pCR) and survival.

Methods

Aligned RNAseq reads of sufficient quality and quantity were obtained for 252 of the 455 pts enrolled in the study, as described previously (Fumagalli et al. JAMA Oncol 2016). Editing sites from the rediPortal database were assessed. The editing level at a given site was computed by counting the number of Gs and As. Sites with coverage more than 10 were considered for further analyses. Editing in normal tissues was obtained from the GTEx project of the rediPortal database. Tumor infiltrating lymphocytes (TILs) and copy number aberrations were previously reported. Correlations between different parameters were assessed using Spearman correlations (ρ). The Mann-Whitney test was used to relate binary and numerical features. Event-free survival (EFS) analysis was performed using the Cox proportional hazard model.

Results

There was a median of 71470 edited sites per sample. As expected, mean editing per sample correlated with ADAR expression (ρ=59%, p&lt;10-16) and ADAR copy number (ρ=54%, p&lt;10-16). It was also correlated with the IFN-gamma driven signature (ρ=22%, p=0.0005), as well as with ESR1 gene expression (ρ=24%, p=0.0002). Neither ADAR expression nor mean editing was correlated with TILs (ρ=-0.5% and ρ=3%). No relationship between mean editing and pCR or EFS was found. The correlations between editing in NeoALTTO tumor samples and GTEx normal tissues were computed, and the median editing per sample was taken. These median correlations, ranging from 32% to 56%, were not associated with ADAR expression (ρ=-25%, p=6x10-5) nor mean editing (ρ=8%, p=0.19). Of interest, patients whose tumors showed low correlation with editing in normal tissues were associated with poor EFS (p=0.028, HR=0.56 to 0.96) suggesting that deregulation of RNA editing may impact disease progression and outcome. Similar results were obtained when the correlations were assessed between tumor samples instead of between tumor and normal samples (ρ between the two median editing: 76%; p-value survival: 0.013). The median correlations were not predictive for pCR (p=0.44). There was no interaction between editing and treatment arm.

Conclusions

Our study shows for the first time that deregulated RNA editing, as compared to editing in normal tissues, is a widespread phenomenon in HER2+ BC patients treated in the NeoALTTO trial and is associated with poor outcome. These results may provide new perspectives for the treatment of HER2+ disease by developing therapies targeting RNA editing.

Citation Format: Venet D, Rothé F, Dupont F, Maetens M, Fumagalli D, Salgado R, Bradbury I, Pusztai L, Harbeck N, Izquierdo M, de la Pena L, Ignatiadis M, de Azambuja E, Huober J, Nuciforo P, Baselga J, Piccart M, Loi S, Sotiriou C. Deregulation of A-to-I RNA editing is associated with poor prognosis in HER2+ breast cancers in the neoALTTO trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-05-04.

A transatlantic perspective on the integration of immuno-oncology prognostic and predictive biomarkers in innovative clinical trial design

Immuno-therapeutics aim to activate the body's own immune system against cancer and are one of the most promising cancer treatment strategies, but currently limited by a variable response rate. Biomarkers may help to distinguish those patients most likely to respond to therapy; they may also help guide clinical decision making for combination therapies, dosing schedules, and determining progression versus relapse. However, there is a need to confirm such biomarkers in preferably prospective clinical trials before they can be used in practice. Accordingly, it is essential that clinical trials for immuno-therapeutics incorporate biomarkers. Here, focusing on the specific setting of immune therapies, we discuss both the scientific and logistical hurdles to identifying potential biomarkers and testing them in clinical trials.

The prevalence and clinical relevance of tumor-infiltrating lymphocytes (TILs) in ductal carcinoma in situ of the breast

Background

Tumor-infiltrating lymphocytes (TILs) are a robust prognostic adjunct in invasive breast cancer, but their clinical role in ductal carcinoma in situ (DCIS) has not been ascertained.

Patients and methods

We evaluated the prevalence and clinical relevance of TILs in a well annotated series of 1488 consecutive DCIS women with a median follow-up of 8.2 years. Detailed criteria for TILs evaluation were pre-defined involving the International Immuno-Oncology Biomarker Working Group. TILs percentage was considered both as a continuous and categorical variable. Levels of TILs were examined for their associations with ipsilateral breast event (IBE), whether in situ or invasive.

Results

Of the 1488 patients with DCIS under study, 35.1% had <1%, 58.3% 1-49% and 6.5% ≥50% peri-ductal stromal lymphocytes. The interobserver agreement in TILs evaluation, measured by the intraclass correlation coefficient (ICC) was 0.96 (95% CI 0.95-0.97). At univariable analysis, clinical factors significantly associated with TILs (P ≤0.001) were intrinsic subtype, grade, necrosis, type of surgery. Her-2 positive DCIS were more frequently associated with TILs (24% of patients with TILs ≥50%), followed by the triple negative (11%), Luminal B/Her-2 positive (9%) and Luminal A/B subtypes (1%) (P < 0.0001). We did not find any association between TILs as a continuous variable and the risk of IBEs. Likewise, when patients were stratified by TILs percentage (<1%, between 1% and 49.9%, and ≥50%), no statistically significant association was observed (10-year cumulative incidence of IBEs: 19%, 17.3%, and 18.7% respectively, P = 0.767).

Conclusion

TILs occur more frequently in the Her-2 positive DCIS. Although we did not find a significant association between TILs and the 10-year risk of IBE, our data suggest that immunotherapies might be considered in subsets of DCIS patients.

Somatic mutation, copy number and transcriptomic profiles of primary and matched metastatic estrogen receptor-positive breast cancers

BACKGROUND

Estrogen receptor-positive (ER+) breast cancers (BCs) constitute the most frequent BC subtype. The molecular landscape of ER+ relapsed disease is not well characterized. In this study, we aimed to describe the genomic evolution between primary (P) and matched metastatic (M) ER+ BCs after failure of adjuvant therapy.

MATERIALS AND METHODS

A total of 182 ER+ metastatic BC patients with long-term follow-up were identified from a single institution. P tumor tissue was available for all patients, with 88 having matched M material. According to the availability of tumor material, samples were characterized using a 120 mutational hotspot qPCR, a 29 gene copy number aberrations (CNA) and a 400 gene expression panels. ESR1 mutations were assayed by droplet digital PCR. Molecular alterations were correlated with overall survival (OS) using the Cox proportional hazards regression models.

RESULTS

The median follow-up was 6.4 years (range 0.5-26.6 years). Genomic analysis of P tumors revealed somatic mutations in PIK3CA, KRAS, AKT1, FGFR3, HRAS and BRAF at frequencies of 41%, 6%, 5%, 2%, 1% and 2%, respectively, and CN amplification of CCND1, ZNF703, FGFR1, RSF1 and PAK1 at 23%, 19%, 17%, 12% and 11%, respectively. Mutations and CN amplifications were largely concordant between P and matched M (>84%). ESR1 mutations were found in 10.8% of the M but none of the P. Thirteen genes, among which ESR1, FOXA1, and HIF1A, showed significant differential expression between P and M. In P, the differential expression of 18 genes, among which IDO1, was significantly associated with OS (FDR < 0.1).

CONCLUSIONS

Despite the large concordance between P and matched M for the evaluated molecular alterations, potential actionable targets such as ESR1 mutations were found only in M. This supports the importance of characterizing the M disease. Other targets we identified, such as HIF1A and IDO1, warrant further investigation in this patient population.