Frequent HER2 Research Articles

Immunotherapy in Breast Cancer.

Breast cancer is a disease encompassing a spectrum of molecular subtypes and clinical presentations, each with distinct prognostic implications and treatment responses. Breast cancer has traditionally been considered an immunologically "cold" tumor, unresponsive to immunotherapy. However, clinical trials in recent years have found immunotherapy to be an efficacious therapeutic option for select patients. Breast cancer is categorized into different subtypes ranging from the most common positive hormone receptor (HR+), human epidermal growth factor receptor 2 (HER2)-negative type, to less frequent HER2- positive breast cancer and triple-negative breast cancer (TNBC), highlighting the necessity for tailored treatment strategies aimed at maximizing patient outcomes. Despite notable progress in early detection and new therapeutic modalities, breast cancer remains the second leading cause of cancer death in the USA. Moreover, in recent decades, breast cancer incidence rates have been increasing, especially in women younger than the age of 50. This has prompted the exploration of new therapeutic approaches to address this trend, offering new therapeutic prospects for breast cancer patients. Immunotherapy is a class of therapeutic agents that has revolutionized the treatment landscape of many cancers, namely melanoma, lung cancer, and gastroesophageal cancers, amongst others. Though belatedly, immunotherapy has entered the treatment armamentarium of breast cancer, with the approval of pembrolizumab in combination with chemotherapy in triple-negative breast cancer (TNBC) in the neoadjuvant and advanced settings, thereby paving the path for further research and integration of immune checkpoint inhibitors in other subtypes of breast cancer. Trials exploring various combination therapies to harness the power of immunotherapy in symbiosis with various chemotherapeutic agents are ongoing in hopes of improving response rates and prolonging survival for breast cancer patients. Biomarkers and precise patient selection for the utilization of immunotherapy remain cardinal and are currently under investigation, with some biomarkers showing promise, such as Program Death Lignat-1 (PDL-1) Combined Positive Score, Tumor Mutation Burden (TMB), and Tumor Infiltrating Lymphocytes (TILs). This review will present the current landscape of immunotherapy, particularly checkpoint inhibitors, in different types of breast cancer.

Spectrum of HER2 alterations in NSCLC: Comparative analysis of tissue and liquid biopsies in lung cancer.

e20602 Background: Non-Small Cell Lung Cancer (NSCLC) exhibits a spectrum of molecular alterations that play a crucial role in understanding its heterogeneity and tailoring targeted therapies. Among these alterations, HER2 aberrations have gained significance as potential therapeutic targets. This study aims to explore the diversity of HER2 changes in NSCLC through tissue and liquid biopsies, providing valuable insights into the feasibility and accuracy of either method. Methods: Data from next generation sequencing of 799 tissues and 1380 liquid biopsy specimens was retrospectively analyzed. The study sought to elucidate the prevalence of HER2 alterations with these two methodologies, evaluating their respective strengths and limitations in detecting HER2 changes in NSCLC. Results: HER2 mutations were identified in 2.1% (17/799) of tissue, mirroring the prevalence observed in the TCGA cohort (2%). The liquid biopsy cohort identified Her2 mutations with similar prevalence and was positive for Her2 mutations in 2.2% (30/1380). Within Her2 mutations, HER2 exon 20 insertion mutations emerged as the predominant variant, accounting for all variants in tissue samples and 93.3% (28/30) in liquid biopsies. The most frequent HER2 exon 20 variant was p.Y772_A775dup variant (76.5% in tissue, 71.4% in liquid biopsy), followed by p.E770_A771insAYVM (17.6% in tissue and 7.1% in liquid). Less frequent HER2 mutations included p.G776delinsLC, p.G776delinsVC, p.V777_G778insGSP, p.A775_G776insYVMA. HER2 amplification was detected in 1.4% (5/352) of tissue and 1.3% (8/617) of liquid biopsy samples; concurrent HER2 mutation and Her2 amplification were detected in 3 liquid biopsy samples. 11/60 cases had concurrent targetable alterations in other targetable genes. Most common concurrent alterations were in EGFR followed by KRAS. Concurrent EGFR sensitizing alterations were observed in 7 patients ( 6 EGFR Exon 19 deletion and one EGFR L858R). Only 2/7 patients showed concurrent EGFR/HER2 alterations at baseline, the remaining 5/7 patients had received prior EGFR TKI therapy. Conclusions: Our results demonstrate equivalent Her2 alteration detection rate with liquid biopsy as compared to tissue molecular profiling in NSCLC. Our results support utility of liquid biopsy for Her2 profiling in the primary setting as well as to detect acquired Her2 alterations like in patients post EGFR-TKI therapy. It highlights that HER2mutations coexist with HER2 amplification in subset of advanced NSCLC patients. [Table: see text]

Therapeutic target biomarkers of patient-derived xenograft models of gastric-type cervical adenocarcinoma

BackgroundMost cervical adenocarcinomas are associated with human papillomavirus (HPV). Gastric-type cervical adenocarcinoma (GAS), an HPV-independent adenocarcinoma, shows an aggressive clinical feature, resulting in a poor prognosis. Resistance to chemotherapy poses a difficulty in managing patients with metastatic GAS. We aimed to establish patient-derived xenografts (PDXs) of tumors from two patients with GAS and evaluated protein biomarkers for drug development using immunohistochemistry. MethodsTwo PDXs were established 78 and 48 days after transplanting the patient’s tumor tissues into immunodeficient mice, respectively. PDX and patient’s tumor samples were stained for HER2, HER3, PMS2, MSH6, PanTrk, and ARID1A to evaluate biomarkers for therapeutic targets. In addition, whole exome sequencing and RNA sequencing were performed on available samples. ResultsThe pathological findings in morphological features and immunohistochemical profiles from the established PDXs were similar to those from the patients’ surgical tumor specimens. HER3 was overexpressed in the patient’s tumors, and the corresponding PDX tumors and HER2 was weakly stained in both types of tumor samples. In all PDX and patient tumor samples, PMS2, MSH6, and ARID1A were retained, and PanTrk was not expressed. In addition, a total of 10 samples, including tumor tissue samples from 8 other GAS patients, were evaluated for HER3 expression scores, all of which were 2 + or higher. ConclusionsIn summary, we evaluated biomarkers for therapeutic targets using newly established PDX models of GAS. Frequent HER3 overexpression and HER2 expression in GAS tumors suggest the possibility of new treatments for patients with GAS by targeting HER3 and HER2.

First-line (1L) panitumumab (PAN) vs bevacizumab (BEV) in patients (pts) with HER2 amplification (HER2amp+), RAS wild type (WT) metastatic colorectal cancer (mCRC) according to tumor sidedness.

53 Background: HER2 gene alterations occur in 3%–5% of pts with mCRC and may be associated with aggressive tumor behavior. Gene amplification is a frequent HER2 alteration in mCRC, often leading to HER2 protein overexpression. Preclinical and retrospective studies suggest HER2 alterations may predict anti–epidermal growth factor receptor (EGFR) therapy resistance in mCRC; however, there is limited information regarding the efficacy of 1L anti-EGFR therapy in mCRC pts with HER2 alterations. The PARADIGM trial demonstrated longer median OS with 1L PAN (anti-EGFR) vs BEV (anti–vascular endothelial growth factor), with mFOLFOX6, in RAS WT mCRC (NCT02394795). We evaluated the efficacy of PAN vs BEV in pts with HER2amp + and HER2amp−, RAS WT mCRC from PARADIGM, taking into account primary tumor sidedness. Methods: Baseline plasma ctDNA was obtained from pts with RAS WT mCRC enrolled in PARADIGM; pts with evaluable pretreatment ctDNA were included in the biomarker analysis (NCT02394834). A custom panel (PlasmaSELECT-R 91, PGDx) was used to detect HER2amp+ and HER2amp− samples. OS, PFS, and response rate (RR) were compared in pts with HER2amp+ vs pts with HER2amp−. Results: Of 802 pts with RAS WT mCRC, 733 (91%) had evaluable pretreatment samples; 32 (4%) had HER2amp + (PAN, n=19; BEV, n=13). A lack of a survival benefit with PAN vs BEV was suggested in pts with HER2amp+, regardless of tumor-sidedness (median OS: overall population, PAN, 23.0 mo; BEV, 26.7 mo; HR, 0.96; 95% CI: 0.45–2.04; left-sided population, PAN, 25.1 mo; BEV, 26.7 mo; HR, 0.89; 95% CI: 0.39–2.04]). Data in the right-sided population are not shown for pts with HER2amp+ due to the small sample size. In the overall population, there was a trend toward shorter OS for HER2amp + vs HER2amp− pts (PAN: 23.0 vs 36.3 mo; HR, 1.57; 95% CI: 0.96–2.57; BEV: 26.7 vs 31.6 mo; HR, 1.41; 95% CI: 0.79–2.52). Median PFS and RR were similar between pts with HER2amp + and HER2amp− in PAN or BEV arms (Table). Conclusions: HER2 amplification appears to be prognostic in pts with RAS WT mCRC but may not be predictive of a survival benefit of 1L PAN treatment over BEV. Clinical trial information: NCT02394834 . [Table: see text]

Abstract 4035: Preclinical activity of BAY 2927088 in HER2 mutant non-small cell lung cancer

Abstract HER2 mutations are potent oncogenic drivers in various cancer indications. In NSCLC, about 2% of patients carry either a HER2 exon20 insertion mutation or a HER2 point mutation. With the recent approval of fam-trastuzumab deruxtecan-nxki, the first targeted treatment option became available for HER2 mutant NSCLC patients. However, there remains a high unmet need for more effective and better tolerated therapies with the potential to improve response rates and response durability. BAY 2927088 is a reversible small molecule inhibitor that is currently being evaluated in a first-in-human, phase I clinical trial in patients with EGFR mutant NSCLC (NCT05099172). Here, we present the preclinical activity profile of BAY 2927088 in HER2 mutant NSCLC. BAY 2927088 shows strong antiproliferative activity in an isogenic Ba/F3 cell line panel of HER2 exon20 insertion mutations as well as HER2 point mutations. BAY 2927088 is highly potent on the most frequent HER2 exon20 insertion mutations A775insYVMA and G776del insVC, as well as in the HER2 point mutations S310F, S335C, and L755S, among others. In addition, the compound was active in a subset of endogenously HER2 mutant cancer cell lines. The in vitro activity of BAY 2927088 was validated in vivo in a patient-derived xenograft model carrying the HER2 exon20 insertion mutation A775insYVMA. The strong preclinical activity of BAY 2927088 in HER2 mutant NSCLC supports clinical evaluation in this indication and might offer a novel targeted therapy option for NSCLC patients that carry HER2 mutations. Citation Format: Franziska Siegel, Gizem Karsli-Uzunbas, Kristyna Kotynkova, Quinn McVeigh, Stephan Siegel, Daniel Korr, Volker Schulze, Markus Berger, Georg Beckmann, Andrew Cherniack, Matthew Meyerson, Heidi Greulich. Preclinical activity of BAY 2927088 in HER2 mutant non-small cell lung cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4035.

Trastuzumab emtansine for patients with non–small cell lung cancer positive for human epidermal growth factor receptor 2 exon-20 insertion mutations

BackgroundHuman epidermal growth factor receptor 2 (HER2) mutations are present in ∼3% of patients with non–small cell lung cancer (NSCLC), with exon-20 insertions accounting for ∼90% of such HER2 mutations and having been identified as driver oncogenic alterations. Antibody–cytotoxic drug conjugates including trastuzumab deruxtecan have shown an excellent efficacy for NSCLC with HER2 mutations. We have now performed a phase II study to evaluate the efficacy of ado-trastuzumab emtansine (T-DM1) for NSCLC positive for HER2 exon-20 insertion mutations. Patients and methodsEligible patients with HER2 exon-20 insertion mutations confirmed by next-generation sequencing or multiplex polymerase chain reaction platforms and a history of one or two lines of chemotherapy received T-DM1 (3.6 mg/kg) intravenously every 21 days. The primary end-point of the study was the objective response rate (ORR). ResultsBetween February 2019 and July 2020, 22 patients were enrolled in the study. A775_G776insYVMA was the most frequent HER2 exon-20 insertion mutation, accounting for 19 (86.4%) of the 22 patients. The ORR was 38.1% (90% confidence interval, 23.0–55.9%), and the disease control rate was 52.4%. The median duration of response was 3.5 months, and the median progression-free survival and median overall survival were 2.8 and 8.1 months, respectively. Toxicity was mild, with the frequency of adverse events of grade ≥3 being low. ConclusionT-DM1 is a potential treatment option for patients with NSCLC with HER2 exon-20 insertion mutations. Further investigation of biomarkers for T-DM1 is warranted to improve its efficacy for NSCLC with such mutations. Clinical trial numberJapicCTI-194620

HER2 Amplification by Next-Generation Sequencing in Lung Carcinoma: A Comparison of NGS Amplified and Non-amplified Cases by Immunohistochemistry and In Situ Hybridization

Background:Although the role of HER2 amplification and its evaluation methods are well known in breast carcinoma, methods for detection of HER2 amplification in non-small cell lung carcinoma are unclear. Next-generation sequencing is widely used in searching multiple therapeutic targets, and it is possible to evaluate copy number variation of genes by next-generation sequencing.Aims:To re-evaluate the HER2 status of non-small cell lung carcinoma cases detected as HER2 amplified and non-amplified by next-generation sequencing via the most commonly used HER2 investigation methods in routine pathology practice, namely immunohistochemistry and in situ hybridization.Study Design:Retrospective cross-sectional study.Methods:Among the 256 patients whose mutation profiles were examined by next-generation sequencing, HER2 amplified (13 cases) and non-HER2-amplified (13 cases) were determined as study and control groups, respectively, by next-generation sequencing. HER2 next-generation sequencing amplified tumors were investigated for HER2 expression and amplification using immunohistochemistry and silver in situ hybridization.Results:From a group of 256 non-small cell lung carcinoma, 33 tumors (12.8%) showed HER2 amplification with next-generation sequencing. Although we observed more frequent HER2 positivity by immunohistochemistry in next-generation sequencing-amplified cases, when compared to non-amplified cases (50% and 23% respectively), the difference was not significant (P = .221). Within the HER2 amplified group, inter-method-agreement was very good between next-generation sequencing results amplification and in situ hybridization status. Next-generation sequencing results showed a strong interclass correlation coefficient with HER2/cell (P = .009, r = 0.777) and HER2/CEP17 ratio (P = .001, r = 0.805). The median HER2/CEP17 ratio was higher in the next-generation sequencing amplified group (P = .013); however, three cases were found to be amplified by silver in situ hybridization among the next-generation sequencing non-amplified cases. EGFR and FGFR1 amplification were more frequent in HER2 next-generation sequencing amplified group than next-generation sequencing non-amplified group (P < .001).Conclusion:Until the effects of HER2 amplification on the HER2 protein are well understood and pulmonary carcinoma algorithms are defined, non-small cell lung carcinomas found to be amplified by next-generation sequencing should be verified by additional methods.

HER2 Expression in Circulating Tumour Cells Isolated from Metastatic Breast Cancer Patients Using a Size-Based Microfluidic Device.

Simple SummaryBreast cancer is the most prevalent type of cancer worldwide. By late 2020, there were 7.8 million women alive who had been diagnosed with breast cancer during the previous 5 years. HER2 overexpression in breast cancer is associated with poor prognosis. Existing HER2-targeting therapies significantly improved patient outcomes; still, designing these personalized treatments relies on accurate and comprehensive assessment of HER2 alterations. Frequent HER2 status determination during disease monitoring can be performed using circulating tumour cells (CTCs). Using a novel microfluidic device, we isolated and enumerated CTCs from metastatic breast cancer patients and assessed their HER2 expression in a comparative study with the current gold standard technology. CTCs isolated with our microfluidic technology showed to be a valuable biomarker, and their phenotypical analysis hinted utility to discriminate patient populations, although further validation is needed.HER2 is a prognostic and predictive biomarker in breast cancer, normally assessed in tumour biopsy and used to guide treatment choices. Circulating tumour cells (CTCs) escape the primary tumour and enter the bloodstream, exhibiting great metastatic potential and representing a real-time snapshot of the tumour burden. Liquid biopsy offers the unique opportunity for low invasive sampling in cancer patients and holds the potential to provide valuable information for the clinical management of cancer patients. This study assesses the performance of the RUBYchip™, a microfluidic system for CTC capture based on cell size and deformability, and compares it with the only FDA-approved technology for CTC enumeration, CellSearch®. After optimising device performance, 30 whole blood samples from metastatic breast cancer patients were processed with both technologies. The expression of HER2 was assessed in isolated CTCs and compared to tissue biopsy. Results show that the RUBYchipTM was able to isolate CTCs with higher efficiency than CellSearch®, up to 10 times more, averaging all samples. An accurate evaluation of different CTC subpopulations, including HER2+ CTCs, was provided. Liquid biopsy through the use of the RUBYchipTM in the clinic can overcome the limitations of histological testing and evaluate HER2 status in patients in real-time, helping to tailor treatment during disease evolution.

Abstract 1472: Novel EGFR WT sparing, HER2 selective inhibitors for the treatment of HER2 exon 20 insertion driven tumors address a clear unmet medical need

Abstract Activating mutations in ERBB2 receptors are tractable oncogenes in 2-3% of NSCLC patients for whom no approved targeted therapies are available. In this indication, oncogenic mutations in HER2 predominantly affect the tyrosine kinase domain and cluster in exon 20 of the ERBB2 gene. We initiated a drug discovery program aiming at discovering novel HER2 selective inhibitors sparing EGFR WT activity. Focus was set on the most frequent HER2 mutation (ERBB2 A775 insYVMA), which is least sensitive to current compounds tested in clinical trials. Here, we report the identification and pharmacological characterization of novel selective HER2 exon 20 mutation TKIs that differ from currently tested TKIs such as poziotinib, TAK-788 or BDTX-189. We could demonstrate that selective inhibition of oncogenic HER2 signaling abrogates oncogenic signaling in in vitro models. Cell survival and proliferation was reduced, which translated into tumor regressions in preclinical CRISPR engineered xenotransplantation models of HER2 exon 20 mutants. The in vivo efficacy was confirmed in patient-derived tumor models. Our results suggest that HER2 exon 20 insertions can be effectively treated by a potent and highly selective HER2 inhibitor that spares EGFR wild type. These findings warrant the upcoming clinical testing in HER2 mutant NSCLC patients in order to effectively treat this aggressive type of cancer. Citation Format: Ralph A. Neumüller, Birgit Wilding, Dirk Scharn, Dietrich Böse, Valeria Santoro, Daniel Gerlach, Peter Ettmayer, Thomas Gerstberger, Julian Fuchs, Matthias Treu, Stephan Zahn, Anke Baum, Paolo Chetta, Mark Pearson, Darryl B. McConnell, Norbert Kraut, Flavio Solca. Novel EGFR WT sparing, HER2 selective inhibitors for the treatment of HER2 exon 20 insertion driven tumors address a clear unmet medical need [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1472.

HER2 Mutated and Nonmutated Non-small Cell Lung Carcinomas Can Harbor Heterogeneous HER2 Gene Amplification and HER2 Protein Expression.

Molecular analyses have become mandatory for treatment choices in patients with advanced non-small cell lung cancers (NSCLC). Among them, HER2 gene mutation, HER2 gene amplification, and HER2 protein expression consist in potential targets of various treatments. Tumor heterogeneity and overlapping of molecular alterations may cause dilemmas in treatment choices but to date there are few that reported about HER2 with discrepant data. We led a retrospective study evaluating HER2 protein expression and HER2 gene/chromosome 17 copy number variations across different tumor areas and samples from patients with advanced NSCLC harboring HER2 gene mutations and other oncogenic mutations. Among patients with HER2-mutated (10 patients) and nonmutated lung adenocarcinomas (10 patients), we observed frequent heterogeneous HER2 protein expression with no correlation with HER2 gene copy number variations. HER2 gene amplification was observed in 6 patients (3 HER2-mutated and 3 HER2-nonmutated), but with intrasample heterogeneity in 2 cases and intersample heterogeneity in another case. Our small case series emphasizes the potential overlapping and spatial heterogeneity of HER2 alterations in NSCLC, which must be taken into account as a limitation in building predictive strategies accompanying the development of anti-HER2 therapeutic strategies in patients with advanced NSCLC.

Mucinous carcinoma with micropapillary features is morphologically, clinically and genetically distinct from pure mucinous carcinoma of breast

Micropapillary features are seen in pure mucinous carcinoma of breast (PMC), which is termed mucinous carcinoma with micropapillary features (MPMC). However, whether MPMC can be identified as a morphologically, clinically or genetically distinct entity from PMC remains controversial. In this study, a retrospective review of 161 cases of breast mucinous carcinoma was conducted to assess the clinicopathologic features, prognostic implications, and genomic alterations of MPMC and PMC. MPMCs were identified in 32% of mucinous carcinomas showing an excellent interobserver agreement (ICC = 0.922). MPMCs occurred at a younger age and exhibited higher nuclear grade, more frequent lymph nodal metastasis, lymphovascular invasion, and HER2 amplification compared with PMCs. Survival analyses revealed that MPMCs show decreased progression-free survival compared with PMCs in both unmatched and matched cohorts. A similar outcome of distant disease-free survival was observed only in the unmatched cohort. However, no statistical difference in recurrence score was observed between MPMC and PMC using a 21-gene assay. Notably, both MPMCs and PMCs displayed low mutation burden, common mutations affecting TTN, GATA3, SF3B1, TP53, recurrent 6q14.1-q27 losses, and 8p11.21-q24.3 gains. GATA3, TP53, and SF3B1 were recurrently mutated in MPMCs, while PIK3CA mutations were exclusively detected in PMCs. Moreover, MPMCs harbored 17q and 20q gains as well as 17p losses, while PMCs displayed gains at 6p. PI3K-Akt, mTOR, ErbB, and focal adhesion pathways were more frequently deregulated in MPMCs than in PMCs, which may responsible for the aggressive tumor behavior of MPMCs. Our findings suggest that MPMC is morphologically, clinically, and genetically distinct from PMC.

Histopathologic features of breast cancer in Li-Fraumeni syndrome.

Breast cancer is the most common malignancy in female patients with Li-Fraumeni syndrome (LFS), a rare autosomal dominant hereditary syndrome characterized by germline TP53 mutations. Recent studies have shown that the majority of these tumors are estrogen receptor (ER) positive with frequent HER2 co-expression. However, the morphologic features of these tumors have not been as well studied as other germline-associated breast cancers. We evaluated the pathologic features of 27 invasive and in situ carcinomas from patients with known germline TP53 mutations collected through the Li-Fraumeni Consortium. Overall, 60% of cases were HER2 positive and 44% showed ER co-expression. Most DCIS was high nuclear grade with central necrosis and associated periductal fibrosis and lymphocytic response. Invasive carcinomas were mostly of ductal type (NOS), modified Scarff-Bloom-Richardson (mSBR) high grade, with marked nuclear atypia and high mitotic rate. Prominent tumor infiltrating lymphocytes, syncytial growth pattern, or pushing borders were not seen in these tumors. High p53 IHC expression was seen in tumors from individuals with germline TP53 missense mutations whereas little or no protein expression (<1% nuclear expression, null pattern) was seen in tumors from carriers of non-missense mutations. In this study, we report in detail the morphologic features of invasive and in situ carcinomas in LFS. We found that these tumors share features with cancers harboring somatic TP53 mutations but are distinct from BRCA-associated breast cancers.

Impact of age at diagnosis of metastatic breast cancer on overall survival in the real-life ESME metastatic breast cancer cohort

BackgroundYoung age is a poor prognostic factor in early stage breast cancer (BC) but its value is less established in metastatic BC (MBC). We evaluated the impact of age at MBC diagnosis on overall survival (OS) across three age groups (<40, 40 to 60 and > 60 years(y)). MethodsESME MBC database is a national cohort, collecting retrospective data from 18 participating French cancer centers between January 01, 2008 and December 31, 2014. ResultsAmong 14 403 women included, 1077 (7.5%), 6436 (44.7%) and 6890 (47.8%) pts were <40, 40–60 and > 60 y respectively. Pts <40 had significantly more aggressive presentations than other age groups: more frequent HER2+ (25.7 vs 15.3% in >60y) and triple negative subtypes (27.4 vs 14.6% in >60y), and more frequent visceral involvement (36.3 vs 29.8% in >60y). At a median follow-up of 48 months, median OS differed across age groups: 38.8, 38.4 and 35.6 months for pts <40, 40–60 and > 60y, respectively (p < 0.0001). Compared to pts <40y, older pts had a statistically significant higher risk of death (all causes of death included), although of limited clinical value (HR = 1.1, IC 95%:1.01–1.20). There was a significant trend for better OS in pts <40y with HER2+ and luminal diseases. A possible explanation is a greater use of anti-Her2 therapies as first-line treatments: 86.6, 81.9 and 74.9% for pts <40, 40–60 and > 60y, respectively (p < 0.0001). ConclusionAlthough young age seems associated with more aggressive presentations at diagnosis of MBC, it has no deleterious effect on OS in this large series.

Clinicopathological characteristics of breast cancer patients with NOD2 mutation according to age

IntroductionThe purpose of the present study was to characterise patients with breast cancer (BC) and NOD2-mutation (age ≥ 50 years) according to their clinicopathological factors or family history. Patients aged ≥ 50 years were compared with the control group and with NOD2-mutation carriers aged < 50 years.Material and methodsPrognostic factors were analysed in patients with BC with confirmed NOD2 c.3016_3017insC (n = 150) mutations. The control group was selected from patients with BC without mutations (n = 376).ResultsThere were significant differences between NOD2-mutation carriers and the control group aged ≥ 50 years, according to HER2 overexpression (p = 0.0001), ER (–) (p = 0.007), PR (–) (p = 0.003), T1–T2 (p = 0.011), and G3 (p = 0.036). Similarly, significant differences were observed between NOD2-mutation carriers and the control group aged < 50 years, according to HER2 overexpression (p = 0.0001), ER (–) (p = 0.049), and N (+) (p = 0.038). In patients aged ≥ 50 years, family history of cancer, including BC, was observed more often in NOD2-mutation carriers compared with the control group of patients (OR = 1.66; p = 0.072, for BC in family history: OR = 2.65; p = 0.002). NOD2-mutation carriers aged ≥ 50 years had significantly less frequent G3 (p = 0.004) and HER2 overexpression (p = 0.043) compared with patients with NOD2 mutation aged < 50 years.ConclusionsThe presence of the NOD2 mutation is not only characteristic of younger patients but also in patients > 50 years of age. In NOD2-mutation carriers aged ≥ 50 years, the presence of larger tumour size, G3, or HER2 overexpression were lower compared with younger patients with NOD2 mutation.

Abstract 3705: Identification of frequent HER2 activating mutations in canine primary pulmonary adenocarcinoma

Abstract Spontaneous primary canine lung cancers are aggressive malignancies that are increasingly common in dogs. They share clinicopathologic features with human lung cancers in never-smokers, but their genetic underpinnings are unknown. As never-smoker lung cancer incidence increases in humans, a need exists for improved biologic understanding and development of new models to fuel translational research. Here, we describe for the first time the detailed clinical and genetic features of primary canine lung cancers through case review and multi-platform sequencing of 90 primary canine lung tumors and cell lines. We performed multi-platform genomic profiling including whole exome sequencing (WES), amplicon panel-based sequencing of 250 regions of 51 cancer genes, and single nucleotide polymorphism (SNP) array-based analysis of tumors and matched constitutional DNA. We profiled 76 cPAC, 11 canine pulmonary adenosquamous carcinomas (cPASC) and three canine pulmonary squamous cell carcinomas (cPSCC). The median age at the time of diagnosis was 11 year old. The most common affected pure breed was the Labrador retriever (19%). Five cPACs assessed by WES displayed low mutation burden with a median of 64 somatic single nucleotide variants (SNVs), 19 somatic copy number variants (CNVs), and 1 structural variant (SV), and frequent C&amp;gt;T substitutions (80%) at NpCpG trinucleotides, a common mutation signature seen across human and canine cancers. Based on WES and amplicon sequencing, we discovered somatic, coding HER2 (ERRB2) point mutations in 37% of cPAC, but none in cPASC or cPSCC. Additional recurrently mutated genes in cPAC included CDKN2A/B (~40%), TP53 (~12%), K/HRAS (~7%), SMAD4 (~5%), and PTEN (~5%). In cPASC, KRAS and TP53 were the most frequently mutated genes (18% each). In cPSCC, no recurrently mutated genes were identified, but individual somatic coding mutations were found in BRAF and PTPN11. The majority (93%) of HER2 mutations were hotspot V659E, located on the transmembrane domain (TMD), and comparable to activating mutations at this same site in human cancer. We were able to detect this mutation not only in biopsied tumors, but also in the plasma of 33% (2/6) of dogs with localized V659E-positive tumors. Other somatic HER2 mutations identified were similarly located in the HER2 juxtamembrane domain and TMD including A664T and K676E. HER2 point mutations occurred in the absence of significant focal amplification (assessed by WES and SNP array) or overexpression (assessed by qRT-PCR and IHC). We also showed that HER2 mutation correlated with constitutive phosphorylation of Akt in cPAC cell lines. Furthermore, HER2 V659E-mutant lines displayed hypersensitivity to the HER2 kinase inhibitors neratinib (IC50, 23nM) and lapatinib (IC50, 168nM) relative to HER2 wild-type cell lines (IC50, &amp;gt;2500nM). These data bear implications for comparative understanding of HER2-mutant lung cancer across species. Citation Format: Gwendolen Lorch, Karthigayini Sivaprakasam, Victoria Zissman, Nieves Perdigones, Tania Contente-Cuomo, Alexandra Nazareno, Salvatore Facista, ShukMei Wong, Winnie Liang, Joseph M. Amann, Sara L. Sinicropi-Yao, Michael J. Koenig, Krista La Perle, Timothy G. Whitsett, Muhammed Murtaza, Jeffrey Trent, David P. Carbone, William P. Hendricks. Identification of frequent HER2 activating mutations in canine primary pulmonary adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3705.

Analysis of HER2 mutant bladder urothelial carcinomas reveals unique mutational signature.

460 Background: Early work has described the presence of HER2 alterations in metastatic urothelial carcinomas (UC), particularly the micropapillary urothelial carcinoma (MPUC) subtype. We reviewed the genomic profiles of a large set of UC cases to further characterize HER2 altered UCs and how such alterations would suggest benefit from the expanding array of anit-HER2 therapeutics. Methods: Tissue from 2,150 UCs were assayed using hybrid capture-based comprehensive genomic profiling (CGP) of 186 to 315 genes plus introns from 14 to 28 genes commonly arranged in cancer. Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA. Results: Within the UC dataset 74.6% of cases were male (1603/2150), with a median TMB of 7 mut/Mb. 383 genomic alterations (GA) of HER2 were identified in 15.5% (334/2150) of cases which exhibited a median TMB of 8.7 mut/Mb (p &lt; 1E-5) vs patients with wildtype HER2, median TMB of 7 mut/Mb. The most frequent HER2 alterations were amplification HER2amp (45.7%, 175/383), S310F (19.8%, 76/383), and S310Y (7/6%, 29/383). Patients harbouring a HER2amp, S310 (n = 105) exhibited a median TMB of 8.7 and 12.2 mut/Mb, respectively. 42 patients presented with multiple ( &gt; 1) HER2 GA and exhibited a median TMB of 11.3 mut/Mb (p &lt; 0.1) vs patients with single HER2 GA, median TMB of 12.3 mut/Mb. Of patients with multiple HER2 alterations, 57% (24/42) harbored a HER2amp. The most common co-occuring HER2 alteration pair was an amplification and extracellular S310X alteration (38.1%, 16/42). Of these 16, the median TMB was 19.5 mut/Mb (average 22.7 mut/Mb). Morphological assessments were performed on the 24 cases harbouring a HER2amp and an additional HER2 GA. 8 cases displayed MPUC features 44.4% (8/18; 6 cases histology unavailable); of these MPUC cases, 75% (6/8), harboured a HER2 amp and S310 extracellular mutation. Conclusions: CGP of bladder urothelial (transitional cell) carcinomas reveals subclasses of HER2 altered cases. Drawing on recent advances in targeting HER2 alterations in breast cancer, dual HER2 blockade (e.g. combinations of mAB/TKI/mAB+ADC) may be needed for HER2amp cases. For cases with both HER2amp and S310 GA, neratinib monotherapy may be the agent of choice and thus may be effective in MPUC.

451 (PB-084) - Elucidation of frequent HER2 overexpression in ductal carcinoma in situ

451 (PB-084) - Elucidation of frequent HER2 overexpression in ductal carcinoma in situ

Abstract B169: Neratinib has clinical activity in HER2-amplified breast cancer patients with tumors that have acquired activating mutations in HER2

Abstract Overexpression/amplification of HER2/ERBB2 occurs in 20% of breast cancers. Thanks to specific anti-HER2 agents, the prognosis of HER2-positive breast cancer has improved considerably. However, acquired resistance inevitably emerges over time and tumors escape pharmacologic pressure. In this work, we propose that acquisition of activating somatic mutations in HER2 upon anti-HER2 therapy may be more frequent than commonly reported and can reduce sensitivity to these agents. Moreover, we tested whether neratinib, an irreversible pan-HER inhibitor, is effective in tumors bearing both amplification and mutations of ERBB2. By targeted exome sequencing, we found that samples from metastatic breast cancer (MBC) patients relapsing to multiple lines of anti-HER2 therapy presented the acquisition of HER2 mutations. These mutations spanned from the extracellular domain (L313I, R456C) to the kinase domain (L755S, D769Y) of the receptor. To investigate the role of these mutations in drug resistance, we conducted functional studies by stably transducing the L755S HER2 mutation (the most frequent HER2 mutation in breast cancer) in two ERBB2-amplified breast cancer cell lines intrinsically sensitive to HER2 inhibition. In both models, we found that expression of L755S mutant-HER2 was sufficient to limit sensitivity to trastuzumab, lapatinib, or the combination of both agents. Consistently, neither trastuzumab nor lapatinib was effective in inhibiting tumor growth of patient-derived xenografts established from a patient with ERBB2-amplified/mutant (D769Y) breast cancer. However, neratinib treatment demonstrated marked sensitivity in this tumor model, resulting in significant tumor growth inhibition. The antitumor activity of neratinib was also explored in breast cancer patients with coexisting ERBB2 amplification and mutation, either by compassionate use after failure of standard-of-care therapy or as part of a “basket” trial (NCT01953926) enrolling ERBB2-mutant patients. In both settings, we observed durable clinical response to neratinib. MBC case #HER2 co-mutationResponse to neratinibDurability of response (mo)1D769YSD62L313ISD93Y772_A775dupSD44L755SSD55V777LPR6 Our findings indicate that acquired HER2 mutations may reduce the effectiveness of therapeutic agents commonly used for the management of ERBB2-amplified MBC. Moreover, we propose neratinib as an effective treatment option for patients whose tumors harbor both ERBB2 amplifications and mutations. Citation Format: Emiliano Cocco, F. Javier Carmona, Helen H. Won, Michael F. Berger, David M. Hyman, Valentina Rossi, Carmen Chan, Alyssa Moriarty, Kyriakos P. Papadopoulos, Michael J. Wick, James Cownie, Ivana Sarotto, Richard E. Cutler, Francesca Avogadri-Connors, Peter Savas, Alshad S. Lalani, Valentina Boni, Sherene Loi, Jose Baselga, Filippo Montemurro, Maurizio Scaltriti. Neratinib has clinical activity in HER2-amplified breast cancer patients with tumors that have acquired activating mutations in HER2 [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B169.

Abstract CT001: Neratinib in HER2 or HER3 mutant solid tumors: SUMMIT, a global, multi-histology, open-label, phase 2 "basket" study

Abstract Background: Somatic HER2 (ERBB2) and HER3 (ERBB3) mutations can lead to constitutive HER2 activation in the absence of gene amplification. They occur in a variety of solid tumors with a prevalence that does not exceed 5-10% in any tumor type. Activating HER2 mutations occur in the HER2 receptor extracellular and transmembrane domains, and at multiple hotspots in the kinase domain, with no single mutation predominating. Neratinib, an irreversible pan-HER tyrosine kinase inhibitor, inhibits growth of HER2- and HER3-mutant tumors in preclinical models. We explored the clinical activity of neratinib in pts with HER2/HER3 mutant cancers in SUMMIT, a global (9 countries), multicenter, multi-histology, phase II ‘basket’ trial. Methods: Pts with advanced solid tumors and locally documented HER2/HER3 mutations received neratinib 240 mg daily with high-dose loperamide prophylaxis during cycle 1. Primary endpoint: objective response rate at week 8 (ORR8) per RECIST 1.1; pts without RECIST-measurable disease were assessed separately using FDG-PET. Retrospective confirmation of HER2/HER3 mutations, as well as a broader cancer gene profiling, was performed using both tumor and plasma-derived cfDNA. For each tumor type, using Simon’s optimal 2-stage design, a true ORR8 ≤10% was considered unacceptable (null hypothesis) whereas a true ORR8 ≥30% (alternative hypothesis) merited further study. Interim data cut: 16-Dec-2016. Clinicaltrials.gov: NCT01953926. Results: 141 (125 HER2, 16 HER3) pts have received neratinib including 125 efficacy-evaluable pts (110 HER2, 15 HER3). 21 unique cancer types were enrolled (most common: breast, lung, bladder, colorectal cancer). 30 HER2 and 12 HER3 mutations were observed, the most frequent HER2 variants involving S310, L755, A755_G776insYVMA and V777. In the HER2-mutant cohort, clinical responses were observed in tumors with S310, L755, V777, P780_Y781insGSP, and A775_G776insYVMA. When stratified by tumor type, responses were observed in pts with breast, cervical, biliary, salivary and non-small-cell lung cancers, which led to indication-specific cohort expansions. No activity was observed in the HER3-mutant cohort. Tumor and/or cfDNA from 116 pts has been sequenced centrally. Of these, the locally reported HER2/3 mutation was confirmed in 108 (93%), a discordant HER2/3 mutation detected in 5 (4%), and not detected in 3 (3%). Co-mutation patterns in different tumor types and their association with neratinib sensitivity/resistance are under review. Conclusions: SUMMIT provides the largest body of clinical data to date on the use of a pan-HER inhibitor in pts with solid tumors with somatic HER2/HER3 mutations. Responses in HER2 mutants varied by type of tumor and the specific HER2 mutation, suggesting: 1) mutant HER2 is a driver oncogene in some cancers; and 2) not all mutations generate the same level of HER2 hyperactivity and/or oncogene dependence. Citation Format: David M. Hyman, Sarina A. Piha-Paul, Jordi Rodon, Cristina Saura, Geoffrey I. Shapiro, David I. Quinn, Victor Moreno, Ingrid A. Mayer, Carlos Arteaga, Valentina Boni, Emiliano Calvo, Sherene Loi, Albert C. Lockhart, Lillian M. Smyth, Joseph Erinjeri, Maurizio Scaltriti, Gary Ulaner, Jean Torrisi, Juber Patel, Jiabin Tang, Fanli Meng, Duygu Selcuklu, Helen Won, Nancy Bouvier, Michael F. Berger, Richard E. Cutler, Feng Xu, Anna Butturini, Lisa D. Eli, Grace Mann, Alshad S. Lalani, Richard P. Bryce, Funda Meric-Bernstam, José Baselga, David B. Solit. Neratinib in HER2 or HER3 mutant solid tumors: SUMMIT, a global, multi-histology, open-label, phase 2 "basket" study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT001. doi:10.1158/1538-7445.AM2017-CT001

Abstract 1465: Analysis of tumor-infiltrating lymphocytes (TILs) reveals biologically different subgroups of breast ductal carcinoma in situ

Abstract Background: Treatment of breast ductal carcinoma in situ (DCIS) aims to prevent invasive recurrence. Recent studies have shown an important impact of TILs on the outcome of invasive breast cancer, however their influence on breast DCIS prognosis has not been fully explored. In this study we investigated whether the amount and/or phenotype of TILs can help recognizing DCIS subgroups of different biology and recurrence risk. Methods: The study included 134 patients, diagnosed and treated for a DCIS from 2001 to 2005 in our institution. Formalin-fixed and paraffin-embedded (FFPE) cancer tissue samples, taken before any treatment, were retrospectively collected. H&amp;E whole tissue sections served for assessment of the cancer size, grade, histotype, architecture, mitotic index and amount of stromal lymphocytic (Ly) infiltrate. The latter was semi-quantitatively graded into 4 grades (0 - absent, 1 - mild, 2 - moderate, 3 - intense). Ly-phenotype was assessed by immunohistochemistry (IHC) on tissue microarrays (TMAs), constructed by sampling each case at the area of the densest Ly-infiltration (3 cores of 0.6 mm diameter per case). The number/mm2 of the CD8+, CD4+, FOXP3+, CD20+ and CD38+ mononuclear cells was determined. TMAs served also for estrogen receptor (ER), progesterone receptor (PR), HER2 and Ki67 IHC staining, as well as for HER2 amplification status. Results: There were 97 DCIS and 37 microinvasive DCIS (micDCIS). The micDCIS displayed significantly more diffuse architecture, frequent HER2 amplification (HER2amp), higher grade, lower ER expression (0.029&amp;lt;p&amp;lt;0.044 for each) and more peritumoral Ly-infiltrate (grades 2+3, micDCIS vs DCIS, 51.5% vs. 39.0%, p = 0.036). All but CD20+ cells were more numerous in micDCIS than in DCIS (0.0016&amp;lt;p&amp;lt;0.05). Within the entire cohort, the cases having the (CD8+/CD4+):(CD20+/CD38+) ratio higher than 1 had a significantly greater risk of containing a microinvasive component (OR 3.47 (1.26-9.57), p = 0.029). Interestingly, that ratio was significantly higher (p = 0.012) in micDCIS than in the DCIS with grade 2 or 3 Ly-infiltrate (Ly-DCIS, n = 38). On the other side, there was no difference between micDCIS and Ly-DCIS in architecture, histograde, HER2amp rate and ER expression. Cluster analysis further confirmed significant similarities between micDCIS and Ly-DCIS, putting them both apart from non-Ly-DCIS (p = 0.0034). The overall 10-year recurrence rate was 13% (18/134 pts). No parameter significantly correlated with recurrence risk, however the micDCIS have received significantly more treatment than DCIS (axillary lymphadenectomy (p&amp;lt;10-7), chemotherapy (p = 0.031) or hormonal therapy (p = 5.4×10-6)). Conclusion: These results indicate that Ly-DCIS might be biologically and immunologically similar to micDCIS. TILs in DCIS are worth investigating in larger studies, as they could be a marker of microinvasion and help tailoring the initial treatment of the disease. Citation Format: Marie Beguinot-Cornillon, Marie-Melanie Dauplat, Fabrice Kwiatkowski, Guillaume Lebouedec, Lucie Tixier, Christophe Pomel, Frederique Penault-Llorca, Nina Radosevic-Robin. Analysis of tumor-infiltrating lymphocytes (TILs) reveals biologically different subgroups of breast ductal carcinoma in situ. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1465.