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Background HER2 alteration (mutation and/or amplification) is associated with poor survival in NSCLC and can mediate resistance to EGFR tyrosine kinase inhibitors. Methods We retrospectively analyzed de-identified molecular information from 12,946 NSCLC samples that underwent next-generation sequencing (NGS) with Caris Life Sciences. The objectives were to determine the prevalence and type of HER2 alterations with and without EGFR as a co-mutation. Insurance claims were utilized to obtain outcomes data. Results Three hundred and twenty-one patients (2.5%) had HER2 alteration: mutation in 197 patients and amplification in 134. Median age was 65 years and 62% were female. A total of 84% were adenocarcinoma. HER2 exon 20 insertion was most common (69%). A total of 1551 (12%) patients had EGFR mutations. Among samples with EGFR mutations, 24 (1.5%) had concurrent HER2 alteration (8 with HER2 mutation and 16 with amplification). Among 8 patients who had both EGFR and HER2 mutations, 3 had EGFR exon 19 deletions and exon 8 HER2 mutation (S310F). One-third of the patients (7/21) with HER2 extracellular domain (ECD) mutation had co-occurring EGFR mutations. All 7 were S310. Patients with concurrent EGFR mutation and HER2 amplification had longer median time on treatment with EGFR TKI(s) than those with EGFR mutation without HER2 amplification (HR 2.284, P =.004). Conclusion A minority of NSCLC samples with EGFR mutations had HER2 alterations. In patients with both mutations, exon 21 mutations for EGFR and exon 8 mutations for HER2 were common. It will be critical to continue to accumulate valuable clinical data for further real-world outcomes analysis.

International audience; Cholangiocarcinoma is a deadly cancer comprising very heterogenous subtypes with a limited therapeutic arsenal in all comers. However, recent significant advances were made with immunotherapy in the first-line treatment of advanced cholangiocarcinoma, with the addition of durvalumab to cisplatin–gemcitabine chemotherapy showing a survival benefit. In the second line setting, only FOLFOX (5FU/folinic acid-oxaliplatin) is validated by a phase 3 trial, yet with a very modest benefit on survival; new options using 5FU with nanoliposomal-irinotecan may emerge in the next few years. The advent of molecular profiling in advanced cholangiocarcinoma in the last decade revealed frequent targetable alterations such as IDH1 mutations, FGFR2 fusions or rearrangements, HER2 amplification, BRAF V600E mutation and others. This strategy opened the way to personalised medicine for patients which are still fit after first-line treatment and the use of targeted inhibitors in first line constitutes a huge challenge with many ongoing trials to improve patients’ care. This review exposes the recent clinical trial findings in non-molecularly selected advanced cholangiocarcinoma, offers a focus on how systematic molecular screening should be structured to allow patients to access to personalised medicine, and details which are the therapeutic options accessible in case of actionable alteration.

Human epidermal growth factor receptor 2 (HER2) amplification or activating mutations are found in 1.6%–4% of non-small cell lung cancer (NSCLC). Pyrotinib has been reported to have better potency in NSCLC patients with HER2 exon 20 insertion (ex20ins) mutations; however, more clinical evidence is urgently needed to guide pyrotinib-based therapy in NSCLC with HER2 amplification or heterogeneous mutations. We retrospectively analyzed advanced NSCLC patients with HER2 amplification or mutations who were treated with pyrotinib-based therapy between September 25, 2018 and October 30, 2020 in our hospital. Molecular dynamics simulation was used to explore the bioactive conformation and binding mechanisms of pan-ErbB tyrosine kinase inhibitors (TKIs) including pyrotinib for different HER2 ex20ins variants. In this study, 79 eligible patients were included with 70 ex20ins variants, 6 missense mutations and 3 primary HER2 amplifications identified. A775_G776insYVMA insertion was the most common observed subtype. The median progression-free survival (mPFS) was 5.8 (95% CI: 4.1–7.4) months. Use of pyrotinib-based therapy in first-/second-line settings showed a significantly better prognosis than that observed in third-line settings or above (mPFS: 9.1 vs. 4.4 months; P = 0.0003). Compared with HER2 amplification and exon 20 non-YVMA insertion variants, patients with HER2 missense mutations had a visible mPFS benefit (12.2 vs. 6.8 vs. 5.2 months). Computational docking simulations revealed that pyrotinib failed to interact with the specific insertion variant P780_Y781insGSP. These results indicated that pyrotinib-based therapy exhibited good anti-tumor activity and acceptable safety profile in HER2-altered advanced NSCLC.

Breast cancer that is characterized by amplification or over expression of human epidermal growth factor receptor 2 (HER2) accounts for 15% to 20% of all forms of the disease. Although HER2 amplification has been associated with aggressive disease behavior and poor prognosis, the development and availability of a number of HER2-targeted agents has led to improved outcomes for patients with HER2-positive metastatic breast cancer, with data suggesting that overall survival has substantially improved in the past 2 decades. An increasing proportion of HER2-positive metastatic breast cancer is diagnosed as de novo stage IV disease. Patients with de novo metastases are traditionally classified in the general category of metastatic breast cancer and not analyzed as a distinct subgroup, though response to therapy and disease outcomes may differ from that of disease that recurred after early stage disease. Among patients with HER2+ de novo metastatic breast cancer, those who achieve a complete response have a prolonged progression-free survival and overall survival. Moreover, the fact that some patients achieve a prolonged durable response has raised interest and renewed discussion about whether cure is feasible in the complex context of metastatic breast cancer. In this review, available data associated with the possibility of cure in the population of patients with HER2+ de novo metastatic breast cancer are presented and discussed in detail.

There are contradictory data regarding the correlation between HER2 amplification level determined by in situ hybridization and evolution after treatment with anti-HER2 therapies. The aim of this study was to correlate quantitative results of FISH (ratio HER2/CEP17 and number of HER2 signals/nucleus) with pathological response achieved after neoadjuvant treatment with trastuzumab and chemotherapy. For this purpose, we analysed 100 consecutive HER2-positive cases of breast carcinoma treated with neoadjuvant therapy. HER2 amplification determined by FISH was found in 92 of the 100 cases studied. pCR was obtained in 58% of the patients whose tumours presented amplification. In contrast, no pCR was obtained in the 8 patients with non-amplified tumours. A significant direct correlation between HER2 high amplification (HER2/CEP17 ratio > 5 or HER2 signals/nucleus > 10) and pCR was found. In conclusion, HER2 amplification levels are clinically relevant because they provide oncologists with valuable information on the possibilities of achieving pCR after neoadjuvant treatment.

Summary: HER2 amplification heterogeneity is associated with resistance to trastuzumab emtansine in the neoadjuvant setting, emphasizing the importance of assessing whether heterogeneous HER2-positive cancers require different treatment pathways. See related article by Metzger Filho et al., p. 2474.

Human epidermal growth factor receptor2 (HER2) overexpression/amplification is associated with high malignancy, rapid disease progression and poor overall survival in breast cancer. The application of anti-HER2 drugs has greatly improved the survival of patients with HER2-positive breast cancer, but drug resistance issues affect the long-term efficacy. The HER2 mutation is considered to be one of the reasons for resistance to anti-HER2 therapy, and there is currently no standard treatment. We report for the first time the detection of HER2 amplification with R157W mutation by second-generation sequencing (NGS) in a 57-year-old hormone receptor-negative, HER2-positive woman with advanced breast cancer who was resistant to multi-line anti-HER2 therapies. She subsequently received pyrotinib combined with capecitabine treatment and achieved partial response. The small-molecule pan-HER family irreversible inhibitor pyrotinib combined with capecitabine has shown a promising effect in the treatment of HER2 mutation-induced resistance, but the molecular mechanism and efficacy need to be further verified.

The clinical benefits of HER2 inhibitors in patients with non-small cell lung cancer (NSCLC) have been limited. There is a paucity of effective therapies in NSCLC after developing resistance to initial anti-HER2 therapy. Herein, we presented the clinical benefit of pyrotinib in a 53-year-old patient with advanced lung adenocarcinoma whose circulating tumor DNA (ctDNA) analysis of pleural effusion revealed the coexistence of HER2 exon 20 p.Y772_A775dup (mutation ratio: 38.86%) and HER2 amplification (copy number: 4.5) following failures of multiple therapies including afatinib and ado-trastuzumab emtansine (T-DM1). Notably, pyrotinib treatment induced rapid and marked improvement of clinical symptoms, and partial response was observed after 8 weeks. CtDNA monitoring during the treatment showed that the mutation ratio of HER2 decreased to 7.99%, and the amplification disappeared. The patient achieved a progression-free survival of 7.5 months after treatment with pyrotinib. Thus, pyrotinib may be a new treatment strategy for the subgroup of lung adenocarcinoma patients, with coexistence of HER2 exon 20 p.Y772_A775dup and HER2 amplification even after failures of multiple anti-HER2 therapies. It also indicated the value of capture-based next-generation sequencing to monitor and guide therapy.

Amplicon-based next generation sequencing (NGS) approaches have been preferentially adopted by the clinical laboratories on the basis of a short turnaround time (TAT) and small DNA input needs. However, little work has been done to assess the amplicon-based NGS methods for copy number variation (CNV) detection in comparison with current standard methods like immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). The correlation between NGS based CNV detection and the later standard methods has remained unexplored. We developed an amplicon-based panel to detect human epidermal receptor growth factor (HER2) amplification in formalin-fixed paraffin-embedded (FFPE) tumor tissue samples from 280 breast cancer and 50 gastric cancer patients. Assessment by IHC and FISH was conducted in parallel, and descriptive statistics were used to assess the concordance. The copy number detected by NGS was correlated with either the average HER2 copy number (signals/cell) (r = 0.844; p

Purpose HER2 overexpression has been identified in approximately 14% of bladder adenocarcinomas. However, until now, there has been no approved standard targeted therapy for bladder adenocarcinoma patients harboring HER2 genetic alteration. Case presentation We presented a case of a 64-year-old man who was diagnosed with bladder adenocarcinoma, and lung metastasis was confirmed less than one year after initial bladder surgery. The patient received systemic chemotherapy and antiangiogenetic treatment, but the tumor continued to progress. The patient underwent next-generation sequencing (NGS) to seek potential treatment opportunities. HER2 amplification, approximately 7 times, was discovered together with the S310F mutation (mutant abundance 90%). The patient then received late-line treatment with trastuzumab and albumin-bound paclitaxel. A partial response was confirmed two months later. Trastuzumab-based therapy was continued for 8 cycles, and the progression-free survival period was 6 months. NGS was performed on a rebiopsy, and the result showed no amplification of HER2, and the S310F mutant abundance was reduced to 27.9%. Conclusion This is the first case report describing a bladder adenocarcinoma patient harboring HER2 amplification who responded to trastuzumab. NGS is of great potential in the selection of bladder adenocarcinoma patients suitable for anti-HER2 therapy. The genetic change after treatment also implied possible mechanisms of resistance to trastuzumab-based therapy, which requires more investigation.

Intratumour heterogeneity fuels carcinogenesis and allows circumventing specific targeted therapies. HER2 gene amplification is associated with poor outcome in invasive breast cancer. Heterogeneous HER2 amplification has been described in 5–41% of breast cancers. Here, we investigated the genetic differences between HER2‐positive and HER2‐negative admixed breast cancer components. We performed an in‐depth analysis to explore the potential heterogeneity in the somatic mutational landscape of each individual tumour component. Formalin‐fixed, paraffin‐embedded breast cancer tissue of ten patients with at least one HER2‐negative and at least one HER2‐positive component was microdissected. Targeted next‐generation sequencing was performed using a customized 53‐gene panel. Somatic mutations and copy number variations were analysed. Overall, the tumours showed a heterogeneous distribution of 12 deletions, 9 insertions, 32 missense variants and 7 nonsense variants in 26 different genes, which are (likely) pathogenic. Three splice site alterations were identified. One patient had an EGFR copy number gain restricted to a HER2‐negative in situ component, resulting in EGFR protein overexpression. Two patients had FGFR1 copy number gains in at least one tumour component. Two patients had an 8q24 gain in at least one tumour component, resulting in a copy number increase in MYC and PVT1. One patient had a CCND1 copy number gain restricted to a HER2‐negative tumour component. No common alternative drivers were identified in the HER2‐negative tumour components. This series of 10 breast cancers with heterogeneous HER2 gene amplification illustrates that HER2 positivity is not an unconditional prerequisite for the maintenance of tumour growth. Many other molecular aberrations are likely to act as alternative or collaborative drivers. This study demonstrates that breast carcinogenesis is a dynamically evolving process characterized by a versatile somatic mutational profile, of which some genetic aberrations will be crucial for cancer progression, and others will be mere ‘passenger’ molecular anomalies., This in‐depth analysis of 10 breast cancers with heterogeneous HER2 gene amplification illustrates that HER2 positivity is not an unconditional prerequisite for the maintenance of tumour growth. This study demonstrates that breast carcinogenesis is a dynamically evolving process characterized by a versatile somatic mutational profile: some genetic aberrations will be crucial for cancer progression, and others will be mere ‘passenger’ molecular anomalies.

Jiadi Gan, Yihua Huang, Jun Liao, Lanlan Pang, Wenfeng Fang Department of Medical Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510060, People’s Republic of ChinaCorrespondence: Wenfeng FangDepartment of Medical Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, 510060, Peoples Republic of ChinaEmail fangwf@sysucc.org.cnBackground: HER2 (or ERBB2) amplification is an important mechanism for acquired resistance to EGFR tyrosine kinase inhibitors (TKI). The benefits of HER2-targeted therapy have been limited. Herein, we investigated the molecular and clinical patterns of HER2 amplification in non-small cell lung cancer (NSCLC) patients during progression on EGFR-TKIs and the potential of combining EGFR-TKI and pyrotinib to overcome resistance.Methods: In this study, 1,637 NSCLC cases from Geneseeq after progression of EGFR-TKIs were screened and analyzed by next generation sequencing (NGS), in which 48 patients with HER2 amplification were eligible and enrolled. A total of 403 patients from Sun Yat-sen University Cancer Center (SYSUCC) were screened and five patients with concomitant EGFR mutations and HER2 amplification were retrospectively collected to assess the effect of afatinib or combination of EGFR-TKI and pyrotinib.Results: In the 48 patients from the Geneseeq cohort, 27 (56.2%) patients suffered from resistance of 1st/2nd generation EGFR-TKI, and 21 (43.8%) patients from 3rd generation. As for the five patients forming the SYSUCC cohort, three patients were treated with afatinib, one achieved partial response (PR) with progression-free survival (PFS) of 6 months and two quickly developed disease progression. Two patients were treated with EGFR-TKIs plus pyrotinib, one receiving gefitinib plus pyrotinib achieved PR with PFS of 8 months and benefited from osimertinib plus pyrotinib for 3 months till data-off; one receiving osimertinib plus pyrotinib achieved SD for 4 months till data-off. The most common co-occurring alteration was TP53 (91.7%) in the mutation profile of the 48 patients from the Geneseeq cohort, and four patients had TP53 co-mutations of the five patients from the SYSUCC cohort.Conclusion: In this study, we detected 7% HER2 amplification present in EGFR-TKIs resistance. Patients with concomitant EGFR mutation and HER2 amplification may derive clinical benefit from therapies that target both EGFR and HER2.Keywords: non-small cell lung cancer, NSCLC, epidermal growth factor receptor tyrosine kinase inhibitors, EGFR TKIs, acquired resistance, combined therapy

Purpose of review This review aims to introduce the resistance mechanisms to osimertinib, discuss the therapeutic strategies, and make clinical updates in overcoming resistance to osimertinib. Recent findings Osimertinib has shown favorable efficacy on second-line and first-line treatments in EGFR-mutant advanced nonsmall cell lung cancer (NSCLC). However, the presence of primary and acquired resistance to osimertinib restricts its clinical benefits. The primary resistance mainly consists of BIM deletion polymorphism and EGFR exon 20 insertions. Meanwhile, the heterogeneous mechanisms of acquired resistance include EGFR-dependent (on-target) and EGFR-independent (off-target) mechanisms. EGFR C797S mutation, MET amplification, HER2 amplification, and small cell lung cancer transformation were identified as frequent resistance mechanisms. Recently, more novel mechanisms, including rare EGFR point mutations and oncogenic fusions, were reported. With the results of completed and on-going clinical trials, the emerging therapeutic strategies of postosimertinib progression are summarized. Summary The resistance mechanisms to osimertinib are heterogeneous and gradually perfected. The combination of osimertinib with bypass targeted therapy and other therapeutic approaches emerge as promising strategies.

Protein tyrosine kinases of the human epidermal growth factor receptor family, including EGFR and HER2, have emerged as important therapeutic targets in non-small-cell lung, breast and gastroesophageal cancers, and are of relevance for the treatment of various other malignancies (particularly colorectal cancer). Classic activating EGFR exon 19 deletions and exon 21 mutations, and HER2 amplification and/or overexpression, are predictive of response to matched molecularly targeted therapies, translating into favourable objective response rates and survival outcomes. By comparison, cancers with insertion mutations in exon 20 of either EGFR or HER2 are considerably less sensitive to the currently available tyrosine kinase inhibitors and antibodies targeting these receptors. These exon 20 insertions are structurally distinct from other EGFR and HER2 mutations, providing an explanation for this lack of sensitivity. In this Review, we first discuss the prevalence and pan-cancer distribution of EGFR and HER2 exon 20 insertions, their biology and detection, and associated responses to current molecularly targeted therapies and immunotherapies. We then focus on novel approaches that are being developed to more effectively target tumours driven by these non-classic EGFR and HER2 alterations. EGFR exon 19 deletions and exon 21 mutations, and HER2 amplification and/or overexpression, are predictive of response to matched molecularly targeted therapies that have greatly improved patient outcomes. However, insertion mutations in exon 20 of either EGFR or HER2 generally do not confer sensitivity to these therapies. In this Review, the authors discuss the prevalence of EGFR and HER2 exon 20 insertions across cancers, their biology and detection, and associated responses to current molecularly targeted therapies and immunotherapies. In addition, they focus on new therapeutic strategies that are being developed to target tumours driven by these non-classic EGFR and HER2 alterations.

Background Gastric cancer (GC) is one of the leading causes of cancer-related deaths worldwide. Human epidermal growth factor receptor 2 (HER2) amplification occurs in approximately 13–23% of all GC cases and patients with HER2 overexpression exhibit a poor prognosis. Lapatinib, a dual EGFR/HER2 tyrosine kinase inhibitor, is an effective agent to treat HER2-amplified breast cancer but it failed in gastric cancer (GC) clinical trials. However, the molecular mechanism of lapatinib resistance in HER2-amplified GC is not well studied. Methods We employed an unbiased, genome-scale screening with pooled CRISPR library on HER2-amplified GC cell lines to identify genes that are associated with resistance to lapatinib. To validate the candidate genes, we applied in vitro and in vivo pharmacological tests to confirm the function of the target genes. Results We found that loss of function of CSK or PTEN conferred lapatinib resistance in HER2-amplified GC cell lines NCI-N87 and OE19, respectively. Moreover, PI3K and MAPK signaling was significantly increased in CSK or PTEN null cells. Furthermore, in vitro and in vivo pharmacological study has shown that lapatinib resistance by the loss of function of CSK or PTEN, could be overcome by lapatinib combined with the PI3K inhibitor copanlisib and MEK inhibitor trametinib. Conclusions Our study suggests that loss-of-function mutations of CSK and PTEN cause lapatinib resistance by re-activating MAPK and PI3K pathways, and further proved these two pathways are druggable targets. Inhibiting the two pathways synergistically are effective to overcome lapatinib resistance in HER2-amplified GC. This study provides insights for understanding the resistant mechanism of HER2 targeted therapy and novel strategies that may ultimately overcome resistance or limited efficacy of lapatinib treatment for subset of HER2 amplified GC.

Purpose HER2 amplification has been implicated in resistance to therapy with anti–epidermal growth factor receptor antibodies (anti-EGFRabs) in metastatic colorectal cancer (mCRC). The purpose of the study was to validate the predictive impact of HER2 amplification in mCRC. Patients and Methods We analyzed patients with RAS/BRAF wild-type mCRC across two distinct cohorts. In cohort 1 (n = 98), HER2 amplification was tested in tumor tissue using dual in situ hybridization ( HER2 amplification: HER2/CEP17 ratio, 2.0 or greater). Cohort 2 (n = 70) included 16 patients with HER2 amplification and 54 HER2 nonamplified controls identified by next-generation sequencing ( HER2 amplification: four or more copies) who had received prior anti-EGFRabs. The primary end point was progression-free survival (PFS) on treatment with anti-EGFRab therapy, which was estimated and compared using the Kaplan-Meier method and log-rank test. Results Median PFS in cohort 1 on anti-EGFRab–based therapy was significantly shorter in patients with HER2 amplification compared with HER2 nonamplified patients (2.8 v 8.1 months, respectively; hazard ratio [HR], 7.05; 95% CI, 3.4 to 14.9; P < .001). These findings were validated in cohort 2 (median PFS for HER2 amplified v nonamplified: 2.8 v 9.3 months, respectively; HR, 10.66; 95% CI, 4.5 to 25.1; P < .001). The median PFS on therapy without anti-EGFRabs was similar among HER2-amplified and nonamplified patients in both cohort 1 (9.7 v 11.1 months, respectively; HR, 1.01; 95% CI, 0.4 to 2.4; P = .97) and cohort 2 (9.6 v 11.3 months, respectively; HR, 1.21; 95% CI, 0.5 to 3.1; P = .66). In multivariable analyses, HER2 amplification emerged as a single independent predictor of poor PFS on anti-EGFRab therapy in both cohort 1 (HR, 6.48; 95% CI, 3.1 to 13.6; P < .001) and cohort 2 (HR, 10.1; 95% CI, 4.3 to 23.9; P < .001). Conclusion HER2 amplification in RAS/RAF wild-type mCRC seems to be a predictive biomarker for lack of efficacy of anti-EGFRab therapy. Screening patients with RAS/BRAF wild-type mCRC for HER2 amplification should be considered before anti-EGFRab treatment to guide therapy and to identify patients for early referral to clinical trials.

Background The incorporation of novel biomarkers into therapy selection for patients with metastatic colorectal cancer (mcrc) has significantly improved outcomes. Optimal treatment planning now takes into account diverse characteristics of patients and their tumours to create personalized therapeutic plans. Discussion This review is split into two sections. In the first section, we review the prognostic and predictive significance of expanded RAS mutation testing, BRAF mutations, ERBB2 (her2) amplification, microsatellite instability (msi) and deficient mismatch repair (dmmr) protein, NTRK fusions, PIK3CA mutations, and met amplifications. The therapeutic implication of each of those biomarkers for personalizing therapies for each patient with mcrc is discussed. In the second section, we touch on testing methods and considerations of relevance to clinicians when they interpret companion diagnostics meant to guide therapy selection. The advantages and pitfalls of various methods are evaluated, and we also look at the potential of liquid biopsies and circulating tumour dna (ctdna) to change the landscape of therapeutic choice and biologic understanding of the disease. Summary Routine testing for extended RAS, BRAF, dmmr or high msi, and NTRK fusions is necessary to determine the best sequencing of chemotherapy and biologic agents for patients with mcrc. Although next generation sequencing and ctdna are increasingly being adopted, other techniques such as immunohistochemistry retain their relevance in detection of her2 amplification, NTRK fusions, and dmmr.

Numerous inherent and acquired genetic alterations have been demonstrated with resistance to anti-epidermal growth factor receptor (anti-EGFR) therapy in metastatic colorectal cancer (mCRC) patients. Although the common oncogenic driver mutations identified include KRAS, NRAS, BRAF, and PI3K, recent studies report a vital role played by human epithelial growth factor receptor-2 (HER2) amplification in acquired resistance to anti-EGFR therapy. HER2 amplification has been associated with poor prognosis in many malignancies including breast and gastric cancer and is also a negative predictor of anti-EGFR therapy. Given the relevance of HER2 amplification in conferring an anti-EGFR resistance, this paper reviews the prevalence of HER2 amplification in mCRC while exploring the prognostic and predictive values of this biomarker. Further, we also discuss the results of the studies that explored the utilization of anti-HER2-targeted therapies in mCRC. HER2-directed therapies have the ability to change the treatment algorithm in clinically relevant small subset of patients with HER2-amplified mCRC.

Objectives Since studies regarding the effect of polysomy 17 (P17) in breast cancer cases with some specific clinical findings are few in number and are in small sample sizes, meta-analysis was implemented to exhibit the effects of P17 in patients with Human Epidermal growth factor Receptor 2 (HER2) amplification on lymph node involvement and tumor grade. Materials and methods Pubmed literature database was scanned up to June 2017 by using the keywords “polysomy 17 breast cancer” and 141 studies were accessed. Ultimately four of the reviewed papers have been found to be appropriate for examining the effect of P17 on lymph node involvement and tumor grade. Prior to meta-analysis, publication bias and heterogeneity of the studies was examined. Results Meta-analysis in the examining the effect of polysomy 17 on lymph node involvement (OR=1.708, 95% CI: 1.068–2.733), on grade [3]/[3,1] (OR=3.402, 95% CI: 1.726–6.707), on grade [3]/[3, 2] (OR=2.581, 95% CI: 0.778–8.559) and on grade [2]/[2,1] (OR=1.854, 95% CI: 0.531–6.468) was determined in those with HER2 amplification. Conclusion It was observed that in terms of lymph node involvement, P17 was a risk factor in patients and with regard to tumor grade, P17 was a risk factor when grade increased in patients with amplification.

Progression of non-muscle-invasive bladder cancer (NMIBC) to muscle-invasive disease (MIBC) significantly worsens life expectancy. Its risk can be assessed by clinicopathological factors according to international guidelines. However, additional molecular markers are needed to refine and improve the prediction. Therefore, in the present study, we aimed to predict the progression of NMIBCs to MIBC by assessing p53 expression, polysomy of chromosome 17 (Chr17) and HER2 status in the tissue specimens of the tumors of 90 NMIBC patients. Median follow-up was 77 months (range 2–158). Patients with Chr17 polysomy or HER2 gene amplification had a higher rate of disease progression (hazard ratio: 7.44; p < 0.001 and 4.04; p = 0.033, respectively; univariate Cox regression). Multivariable Cox regression models demonstrated that the addition of either Chr17 polysomy or HER2 gene amplification status to the European Association of Urology (EAU) progression risk score increases the c-index (from 0.741/EAU/ to 0.793 and 0.755, respectively), indicating that Chr17 polysomy/HER2 amplification status information improves the accuracy of the EAU risk table in predicting disease progression. HER2/Chr17 in situ hybridization can be used to select non-progressive cases not requiring strict follow-up, by reclassifying non-HER2-amplified, non-polysomic NMIBCs from the high- and very high-risk groups of EAU to the intermediate-risk group.

Objectives To examine and compare human epidermal growth factor receptor 2 (HER2) amplification status in high-grade urothelial carcinoma (HGUCa), using both 2013 and 2018 HER2 reporting guidelines for breast carcinoma from the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP). Methods HER2 status by fluorescence in situ hybridization (FISH) assay in 78 cases of HGUCa was compared using 2013 and 2018 HER2 reporting guidelines. Results HER2 amplification was observed in 22 (28.2%) of 78 tumors, of which 17 were in group 1, 1 in group 2, and 2 each in groups 3 and 4 (FISH assay, 2018). The remaining 14 HER2-amplified tumors (FISH assay, 2013) became negative, falling into group 2 (FISH assay, 2018) and were either negative or equivocal on immunohistochemistry (IHC, 2018). All FISH-negative tumors (n = 37) using 2013 criteria remained negative (group 5, 2018). FISH-equivocal tumors (2013) were further categorized into HER2 amplified (n = 1) and HER2 negative (n = 4) (2018). Overall, 20 (25.6%) tumors had discordant HER2 FISH results (2018 vs 2013). Conclusions Implementing 2018 guidelines, HER2 amplification decreased from 36 to 22 cases. The group with a HER2/CEP17 ratio of 2 or more and average HER2 copy number less than 4 (group 2) were predominantly negative by IHC, suggesting a biologically distinct group of HGUCa that is different from HER2-amplified tumors, which may not respond to HER2-targeted therapy.

BackgroundNon-small cell lung cancer (NSCLC) patients with HER2 mutations and amplification may benefit from HER2-targeted therapy, including afatinib. However, the data regarding the clinical activity of afatinib in Chinese patients with NSCLC harboring HER2 alterations are limited.Patients and methodsWe retrospectively included metastatic NSCLC patients harboring HER2 alterations who treated with afatinib. The clinical outcomes included overall response rate (ORR), progression-free survival (PFS) and overall survival (OS). The genomic profiling data after progression on afatinib were analyzed.ResultsWe included 54 patients harboring HER2 mutations and 12 patients harboring HER2 amplification. The ORR was 24% (95% CI, 16–36%), the median PFS was 3.3 months (95% CI, 2.2–4.4), and the median OS was 13.9 months (95% CI, 11.4–16.5). Patients with HER2 exon 20 mutations had numerically worse ORR (17% vs 42%), shorter PFS (2.6 vs 5.8 months, HR, 2.5; 95% CI, 1.2–5.5; P = 0.015) and OS (12.9 vs 33.3 months, HR, 4.4; 95% CI, 1.3–14.8; P = 0.009) than patients with other mutations. For HER2-amplified patients, the ORR was 33% (95% CI, 14–61%), the median PFS was 3.3 months (95% CI, 2.6–4.0), and the median OS was 13.4 months (95% CI, 0–27.6). The most frequently mutated genes in afatinib-resistant patients were TP53 (44%) and EGFR (33%). Three afatinib-resistant patients harbored secondary HER2 alterations.ConclusionsOur results suggest that afatinib has a promising anti-tumor activity in patients with NSCLC harboring HER2 alterations. To our knowledge, this is the largest retrospective study about the clinical activity of afatinib in NSCLC patients with HER2 alterations.

Non-small-cell lung cancer (NSCLC) harbouring HER2 alterations is now considered a distinct molecular subtype. The activation of HER2 in NSCLC occurs via three mechanisms, i.e. gene mutation (1%-4% of cases), gene amplification (2%-5%) and protein overexpression (2%-30%), with different prognostic and predictive outcomes. So far, non-selective tyrosine kinase inhibitors (TKIs) have shown a minor benefit in HER2-mutant NSCLC patients with objective response rates (ORRs) ranging from 0% to 19%. Trastuzumab-based chemotherapy was not found to be superior to chemotherapy alone [median progression-free survival (PFS) 6.1 versus 7 months, respectively] and dual HER2 antibody blockade with trastuzumab and pertuzumab had limited efficacy (ORR 13%-21%). In contrast, novel more selective HER2 TKIs such as poziotinib and pyrotinib have shown a promising activity in HER2-mutant pre-treated NSCLC patients, with response rates up to 38% and 44%, respectively. The most encouraging data come from phase II studies that evaluated the antibody–drug conjugates (ADCs) ado-trastuzumab–emtansine and trastuzumab–deruxtecan in patients with HER2-mutant NSCLC, with response rates of 50% and 62%, respectively. These agents are bringing hope to the management of HER2-altered NSCLC. Moreover, a paradigm shift from monotherapies towards combinations of agents with distinct mechanisms of action, such as ADCs with irreversible TKIs or immune checkpoint inhibitors, is already taking place and will change the therapeutic landscape of HER2-driven NSCLC. This paper provides a practical, concise and updated review on the therapeutic strategies in NSCLC with HER2 molecular alterations., Highlights • Activation of Her2 in NSCLC occurs via gene mutation, amplification or protein overexpression. • Selective Her2 TKIs like poziotinib and pyrotinib induced responses in up to 44% of pre-treated Her2-mutant NSCLC patients. • ADCs trastuzumab–emtansine and trastuzumab–deruxtecan showed impressive response rates in 62% of Her2-mutant NSCLC patients. • Ongoing studies evaluating combination strategies may help improve the therapeutic landscape in Her2-dependent NSCLC.

Clinical Practice Points • HER2 amplification is an acquired resistance mechanism in ALK-rearranged non–small cell lung cancer. • FISH analysis revealed a minor subclone of HER2-amplified cells before becoming the dominant resistance mechanism. • Combination of HER2 and ALK therapies may be an effective treatment approach for ALK-rearranged NSCLC with acquired HER2 amplification.

PurposeThe DESTINY-Breast04 clinical trial is currently investigating whether trastuzumab deruxtecan (T-DXd) is effective in HER2-low as well as HER2-positive breast cancer. This highlights the interest in treatment strategies for patients with HER2-low breast cancer. The current study was therefore designed to determine the frequency of HER2-low among all breast cancers, and to compare the prognosis of HER2-low patients with that of HER2-negative patients. MethodsWe retrospectively reviewed the biological data from 4,918 of 4,977 primary breast cancer patients who attended our institute. We quantified the overall frequency of breast cancer patients with a new HER2-low subtype that was defined by an immunohistochemistry score of IHC1+ or IHC2+/ISH-. We then compared the clinical characteristics and prognosis of HER2-low patients with that of patients who did not have HER2 amplification (HER2-0). ResultsLow HER2 expression was found in 3169 (64.4%) patients; 2860 (58.1%) were HR-positive and 309(6.3%) were HR-negative. Among HER2-0 patients, 681(13.9%) were HR-positive and 157(3.2%) were HR-negative. The HER2-0 group tended to have more poor prognostic factors than the HER2-low group, irrespective of HR status. There were no statistically significant differences between the prognosis of HER2-low and HER2-0 patients, regardless of HR status. However, patients in the HER2-low group tended to have better prognosis than those in the HER2-0 group.ConclusionHER2-low patients did not have a significantly different prognosis than HER2-0 patients, regardless of HR status. However, we should consider tailoring therapies for patients with HRE2-low early breast cancer according to their HR status.

The reported rates of HER2 positivity in cervical cancer (CC) range from 0% to 87%. The importance of HER2 as an actionable target in CC would depend on HER2 positivity prevalence. Our aim was to provide precise estimates of HER2 overexpression and amplification in CC, globally and by relevant subgroups. We conducted a PRISMA compliant meta-analytic systematic review. We searched Medline, EMBASE, Cochrane database, and grey literature for articles reporting the proportion of HER2 positivity in CC. Studies assessing HER2 status by immunohistochemistry or in situ hybridization in invasive disease were eligible. We performed descriptive analyses of all 65 included studies. Out of these, we selected 26 studies that used standardized American Society of Clinical Oncology / College of American Pathologists (ASCO/CAP) Guidelines compliant methodology. We conducted several meta-analyses of proportions to estimate the pooled prevalence of HER2 positivity and subgroup analyses using geographic region, histology, tumor stage, primary antibody brand, study size, and publication year as moderators. The estimated pooled prevalence of HER2 overexpression was 5.7% (CI 95%: 1.5% to 11.7%) I2 = 87% in ASCO/CAP compliant studies and 27.0%, (CI 95%: 19.9% to 34.8%) I2 = 96% in ASCO/CAP non-compliant ones, p < 0.001. The estimated pooled prevalence of HER2 amplification was 1.2% (CI 95%: 0.0% to 5.8%) I2 = 0% and 24.9% (CI 95%: 12.6% to 39.6%) I2 = 86%, respectively, p = 0.004. No other factor was significantly associated with HER2 positivity rates. Our results suggest that a small, but still meaningful proportion of CC is expected to be HER2-positive. High heterogeneity was the main limitation of the study. Variations in previously reported HER2 positivity rates are mainly related to methodological issues.

Dual HER2-targeted therapy has been associated with clinical responses and prolonged progression-free survival and overall survival in RAS-wild type HER2-amplified colorectal cancer (CRC). However, no clinical benefits have been reported in patients with CRC with HER2 mutations. Activated HER2 mutations have been largely deemed resistant to trastuzumab and to dual HER2 targeting. This report describes a patient with metastatic CRC with concurrent HER2 amplification and a HER2 S310F mutation, which is an active mutation located in the extracellular dimerization domain of HER2. Treatment with trastuzumab + lapatinib resulted in an excellent response that lasted for 10 months. Upon disease progression, treatment with the antibody–drug conjugate trastuzumab–deruxtecan resulted in a short-lived response. This is the first case report of successful HER2 targeting in metastatic CRC with concurrent HER2 amplification and a HER2 S310F mutation.

Over the past years, colorectal cancer (CRC) was subtyped according to its molecular and genetic characteristics, allowing the development of therapeutic strategies, based on predictive biomarkers. Biomarkers such as microsatellite instability (MSI), RAS and BRAF mutations, HER2 amplification or NTRK fusions represent major tools for personalized therapeutic strategies. Moreover, the routine implementation of molecular predictive tests provides new perspectives and challenges for the therapeutic management of CRC patients, such as liquid biopsies and the reintroduction of anti-EGFR monoclonal antibodies. In this review, we summarize the current landscape of targeted therapies for metastatic CRC patients, with a focus on new developments for EGFR blockade and emerging biomarkers (MSI, HER2, NTRK).

HER2 amplification detection assays are widely used as companion diagnostic tools for Herceptin targeted therapy on Breast and Gastric cancer patients. Current tests approved for clinical use are in general IHC or FISH-based and could only be used on tissue samples. This requires tissue processing to generate FFPE slices and subjective results determination by pathologists. Here we report the development and validation of a digital PCR based assay to be used to determine the status of HER2 amplification in both tissue and plasma samples. Interestingly, we have found that the status of HER2 may change during therapy and disease development, supporting the necessity of a liquid biopsy assay for HER2 amplification. Keywords: HER2, Digital PCR, Herceptin targeted therapy, Liquid biopsy, Breast and Gastric cancer

Previous studies demonstrated that AIB1 or HER2 copy number gain (CNG), respectively, were independent predictors for poor prognosis of glioma patients, especially in females. We hypothesize that there are some connections between the two genes and sex-specific characteristics, thus this study aimed to analyze gender-related differences in the prognosis of glioma patients.Using Real-Time Quantitative Reverse Transcription PCR (RT-qPCR) method, we examined AIB1 and HER2 CNG in gliomas samples (n = 114), and inspected the correlation of various genotypes with patients outcomes.Concomitant AIB1 and HER2 amplification were closely related to shorter survival time and radiotherapy resistance in female gliomas patients (P0.01), which also served as an independent risk factor. No significant prognostic value was found with AIB1 and HER2 CNG in male patients. However, linear regression analysis showed a positive relationship between the copy number of AIB1 and HER2 (P0.01) in male patients, rather than female patients.In this study, we reveal a gender difference in the prognostic value of concomitant AIB1 and HER2 CNG in glioma patients which were barely noticed before. These observations indicated that genetic alterations synergistic with essential respects of sex determination influence glioma biology and patients outcomes.

Purpose Poziotinib, a pan-human epidermal growth factor receptor 2 (HER) tyrosine kinase inhibitor, has shown potent activity againstwild type of epidermal growth factorreceptor(EGFR) family kinases including EGFR, HER2, and HER4 and EGFR-mutant cells in vitro. Two phase I studies were conducted to determine the maximum tolerated dose (MTD), pharmacokinetics, safety, and antitumor activity against advanced solid tumors. Materials and methods Standard 3+3 dose escalation scheme using two different dosing schedules were studied: once daily, 14-day on, and 7-day off (intermittent schedule); and once daily continuous dosing with food effect. Additional patients were enrolled in an expansion cohort. Results A total of 75 patients were enrolled in the two studies. The most common drug-related treatment-emergent adverse eventswere diarrhea,rash, stomatitis, pruritus, and anorexia. Doselimiting toxicities were grade 3 diarrhea in the intermittent schedule and grade 3 anorexia and diarrhea in the continuous dosing schedule. The MTDs were determined as 24 mg/day in the intermittent dosing schedule and 18 mg/day in the continuous dosing schedule. Eight (16%) and 24 (47%) of 51 evaluable patients in the intermittent schedule achieved partial response (PR) and stable disease (SD), respectively. Four (21%) and six (32%) of 19 evaluable patients in continuous dosing schedule achieved PR and SD, respectively. Patients with PR (n=7) or SD ≥ 12 weeks (n=7) had HER2 amplification (n=7; breast cancer, 5; and stomach cancer, 2) and EGFR amplification (n=1, squamous cell lung cancer). Conclusion Poziotinib was safe and well tolerated in patients with advanced solid tumors. It showed an encouraging activity against EGFR-mutant and HER2-amplified cancers.

Improved clinical selection and identification of new molecules and innovative strategies have widened treatment options and increased overall survival in metastatic colorectal cancer patients in recent years. Biomarker-driven therapies represent an emerging issue in this field and new targeted treatments are under investigation and probably will be soon adopted into daily clinical practice. In the present review, the role RAS, BRAF mutations, Her2 amplification, microsatellite instability, and CpG island methylator phenotype are discussed according to their possible roles as prognostic, predictive markers, as well as possible biomarker-driven treatment options.

Purpose While HER2 testing is well established in directing appropriate treatment for breast cancer, a small percentage of cases show equivocal results by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Alternative probes may be used in equivocal cases. We present a single community-based institution’s experience in further evaluating these cases. Patients and methods Between 2014 and 2016, 4255 samples were submitted for HER2 amplification testing by alternative probes, TP53, RAI1, and RARA. Of the patients tested by FISH, 505/3908 (12.9%) also had IHC data. Results Most (73.9%) FISH equivocal cases remained equivocal after IHC testing. However, 50.5% of equivocal cases were classified as HER2 amplified by alternative probes. Most cases were positive by more than one probe: 78% of positive cases by RAI1 and 73.9% by TP53. There was a significant difference between IHC and FISH alternative testing (p

Background: HER2 serves as an important therapeutic target in gastroesophageal cancer. Differences in HER2 gene signal distribution patterns can be observed at the tissue level, but how it influences the HER2 amplification status has not been studied so far. Here, we investigated the link between HER2 amplification and the different types of gene signal distribution. Methods: Tumor samples from 140 patients with gastroesophageal adenocarcinoma where analyzed using the HER2 IQFISH pharmDx™ assay. Specimens covered non-amplified and amplified cases with a preselected high proportion of HER2 amplified cases. Based on the HER2/CEN-17 ratio, specimens were categorized into amplified or non-amplified. The signal distribution patterns were divided into homogeneous, heterogeneous focal or heterogeneous mosaic. The study was conducted based on anonymized specimens with limited access to clinicopathological data. Results: Among the 140 analyzed specimens 83 had a heterogeneous HER2 signal distribution, with 62 being focal and 21 of the mosaic type. The remaining 57 specimens had a homogeneous signal distribution. HER2 amplification was observed in 63 of the 140 specimens, and nearly all (93.7%) were found among specimens with a heterogeneous focal signal distribution (p

The main obstacle for designing effective treatment approaches in breast cancer is the extensive and the characteristic heterogeneity of this tumor. The vast majority of critical genomic changes occurs during breast cancer progression, creating a significant variability within primary tumors as well as between the primary breast cancer and their metastases, a hypothesis have already demonstrated in retrospective studies (1). A clear example of this is the HER2-positive breast cancer. In these tumors, we can find all of the transcriptional subtypes of breast cancer, even the basal like or luminal A subtypes. Although the HER2-enriched is the most representative transcriptional subtype in the HER2-positive breast cancer, we can find it too in breast cancers with HER2-negative status. This intrinsic subtype shows a high expression of the HER2 and is associated with proliferation-related genes clusters, among other features. Therefore, two hypotheses can be suggested. First, the HER2 amplification can be a well-defined driver event present in all of the intrinsic subtypes, and not a subtype marker isolated. Secondly, HER2-enriched subtype can have a distinctive transcriptional landscape independent of HER2 amplification. In this review, we present an extensive revision about the last highlights and advances in clinical and genomic settings of the HER2-positive breast cancer and the HER2-enriched subtype, in an attempt to improving the knowledge of the underlying biology of both entities and to explaining the intrinsic heterogeneity of HER2-positive breast cancers.

s Background Human epidermal growth factor receptor 2(HER2) status is a crucial predictive factor for prognostic assessment and targeted therapy selection, which may be influenced by intratumor heterogeneity and molecular divergence between the primary site and different metastases. Therefore, we performed a prospective study to confirm the concordance of HER2 amplification in circulating tumor DNA(ctDNA) with primary tumor tissue and verified its clinical implications. Methods A total of 105 breast cancer patients were enrolled, and dynamic monitoring of HER2 copy numbers in ctDNA was conducted in 31 participants during the treatment. Totally 186 plasma samples were prospectively obtained and blinded to test HER2 copy numbers in ctDNA based on low-coverage whole genome sequencing(WGS) by next-generation sequencing(NGS). Results Comparing HER2 copy numbers in ctDNA collected before the initiation of next line of anticancer treatment with primary tumor tissue, the concordant rate of HER2 amplification was 86.5%(χ2 = 52.901, p, Highlights • The concordance between HER2 amplification in ctDNA and tumor tissues was 86.5%. • The positive and negative predictive value surpassed previous studies. • HER2 copy numbers in ctDNA may predict the prognosis of anti-HER2 therapy. • HER2 copy numbers in ctDNA may predict response in HER2 positive breast cancer. • The study of various-stage patients may be closer to real-world clinical practice.

Cetuximab (CTX) has been used to treat metastatic colorectal cancer (mCRC) with wild-type (wt) RAS and BRAF genes. Meanwhile HER2 amplification reportedly denoted CTX-resistant mCRC tumors. We investigated whether monitoring of HER2 amplification in circulating DNA allowed early detection of mCRC progression and CTX resistance. We analyzed HER2 amplification in circulating DNA at 8-week intervals using ddPCR from 36 patients with RASwt/BRAFwt mCRC, who progressed after CTX treatments between July 2015 and January 2018. Of the 36 patients, 5 (13.9%) exhibited dynamic fluctuations of HER2 amplification in plasma in the course of CTX treatment, of whom 2 were positive for HER2 amplification in matched tumor specimens at baseline (per FISH). All 5 primary sites were left side: 3 rectums and 2 descending colon. HER2 ratio fluctuations in circulating DNA not only reflected changes in tumor volume, but their obvious increases presaged CT-documented progress by an average lead time of 2 months. Interestingly, progression-free survival did not significantly differ between these 5 patients and those without HER2 amplification (HR 1.06, 95% CI 0.40–2.77, P = 0.909). Plasma HER2 amplification detected by ddPCR changed over time and predicted resistance to CTX, by an average lead time of 2 months. Further study is needed to validate our findings.

Purpose Human epidermal growth factor receptor 2 (HER2) alterations are found in approximately 1%-3% of non-small cell lung cancers (NSCLCs). We evaluated the clinical features and outcomes of NSCLC harboring HER2 alteration detected by next-generation sequencing (NGS) in Korea. Materials and methods A total of 1,108 patients who were diagnosed with NSCLC between December 2015 and December 2017 were screened and analyzed by NGS. Medical records were reviewed retrospectively to analyze the clinical characteristics and outcomes from various treatments. Results HER2 alterations were identified in 36 NSCLC patients. Of the patients, 22 (61.1%) had an exon 20 in-frame insertion mutation, 15 (41.7%) had HER2 amplification, and one had both. The median patient age was 58 years, 55.6% were male, and 50.0% were never-smokers. Adenocarcinoma was predominant (88.9%). The most common metastatic site was bone (58.3%), and 66.7% of patients were stage IV at initial diagnosis. Six patients (16.7%) had a coexistent sensitizing epidermal growth factor receptor (EGFR) mutation, and two patients (5.6%) had anaplastic lymphoma kinase (ALK) rearrangement. With a median 14 months of follow-up, the median progression-free survival of first-line treatment was 6 months (95% confidence interval, 4.172 to 7.828), and median overall survival was not reached. The proportions of adenocarcinoma, never-smokers, and metastasis to the liver were higher in the exon 20 in-frame insertion mutation group, whereas coexistence of EGFR mutation was more frequently found in the HER2 amplification group. Conclusion HER2-altered NSCLC showed distinct clinical features. Moreover, different characteristics were identified between the HER2 in-frame insertion mutation group and the HER2 amplification group.

Patients with non-small cell lung cancer (NSCLC) harboring MET exon 14 skipping can benefit from crizotinib treatment. Currently, the main resistance mechanisms to crizotinib are MET D1228N and Y1230C mutations. We reported a case of a Chinese NSCLC patient with MET exon 14 skipping detected by targeted next-generation sequencing (NGS) achieved clinical and imaging remission after crizotinib treatment. Then, amplification of multiple genes such as erb-b2 receptor tyrosine kinase 2 (HER2) was detected when disease progressed, indicating novel resistance mechanisms to crizotinib. Ultimately the patient died from cancer-related factors. This was the first NSCLC case with MET exon 14 skipping which reported the HER2 gene amplification at the time of progression during crizotinib treatment, indicating that bypass mechanisms contribute to the development of acquired resistance to MET inhibitors.

Trastuzumab represents the predominant therapy to target breast cancer subtype marked by HER2 amplification. It has been in use for two decades and its continued importance is underlined by recent FDA approvals of its biosimilar and conjugated versions. Progression to an aggressive disease with acquisition of resistance to trastuzumab remains a major clinical concern. In addition to a number of cellular signaling pathways being investigated, focus in recent years has also shifted to epigenetic and non-coding RNA basis of acquired resistance against trastuzumab. This article provides a succinct discussion on the most recent advances in our understanding of such factors.

TPS3141 Background: The human epidermal growth factor receptor 2 (HER2) gene amplification and mutations have emerged as oncogenic drivers and therapeutic targets not limited to breast and gastric cancers, but also in a variety of cancers. However, even if an actionable gene alteration is found, the incidence of HER2 amplification in these cancers is less than 5%. Despite its considerable therapeutic potential, the evidence is not yet mature enough for use as treatment in clinical practice. To address this unmet clinical need, we have designed an organ-agnostic basket trial, which covers a variety of solid cancers harboring HER2 amplification. Methods: JUPITER trial is a Japanese multicenter, single-arm, phase 2 basket study of combination therapy with trastuzumab and pertuzumab. Patients with solid cancers harboring HER2 amplification, who have progressed with standard treatment, or rare cancers for which there is no standard treatment, are eligible. Types of cancer include bile duct, urothelial, uterine, ovarian, and other solid cancers that HER2 amplification is detected by comprehensive genomic profiling using next-generation sequencing technology. Target sample size is 38. All enrolled patients receive combination therapy with trastuzumab and pertuzumab every 3 weeks until disease progression, unacceptable toxicity, death, or withdrawal of informed consent. Response assessment using RECIST version 1.1 is performed at weeks 9 and 17, followed by every 12 weeks. The primary endpoint is the objective response rate, and secondary endpoints are progression-free survival, overall survival, duration of response, and safety. In total, 40 patients were enrolled by June 2020. Data fix is scheduled in September 2021. Trial registration: jRCT2031180150 Clinical trial information: jRCT2031180150.

593 Background: Digital pathology has fostered the development of automated diagnostic solutions. However, current technologies in breast cancer remain unable to determine HER2 amplification status, which is established by immunohistochemistry (IHC) and/or fluorescent in situ hybridization (FISH). These ancillary tests carry a significant cost, prolong diagnostic time and fail to capture HER2 tumor heterogeneity and tumor infiltrating lymphocyte (TIL) burden, both of which determine the effectiveness anti-HER2 targeted therapy. Methods: This study describes the real-life clinical context development and validation of a patented novel, universal, automated, white-box, scanning platform agnostic solution that determines HER2 amplification status, prognostically significant TIL levels and tumor heterogeneity index (HI) from hematoxylin and eosin (H&E) stained malignant breast biopsy whole slide images (WSIs) alone. Unlike conventional artificial intelligence-based approaches, the underlying proprietary algorithm’s prediction criteria are explainable and are based on deterministic, hard-coded observational relationships of scale constructed from image morphological features mapped to observables representing underlying tumor-related perturbations in biological pathways/mitotic checkpoints.This includes G1/S deregulation signatures reflecting oncogenic HER2-neu. Results: Blinded validation of HER2 status prediction (n = 197 WSIs; 118 independent cases/patients) showed excellent diagnostic performance (κ = 0.85) relative to existing standard-of-care methodologies. This was independent of WSI file format, background histology, tumor subtype/grade or hormone receptor status. The device also displayed good accuracy (92%) in determining TIL profiles, and its combined HER2-TIL and HER2-HI prediction scales both exhibited a significant association with progression-free survival (CoxPH hazard ratio: 1.856; 95% CI: 1.002-3.438; p = 0.049 and CoxPH hazard ratio: 3.45; 95% CI: 0.95-12.55; p = 0.060). Conclusions: This technology opens up the future possibility of bypassing existing ancillary HER2 profiling investigations, thus potentially reducing laboratory workloads/healthcare costs while accelerating diagnostic turnaround times for patient benefit. In the interim, if used as an adjunct tool, this device could provide an objective HER2 testing reference scale while the robustness of its prediction of patient response to anti-HER2 targeted therapy is fully explored.

68 Background: HER2 amplification is an emerging biomarker in colorectal cancer (CRC) with increased copy number associated with improved clinical outcomes to HER2 targeting. RAS/RAF wildtype CRC also benefit from use of epidermal growth factor receptor inhibition (EGFRi). The sequencing of EGFRi versus HER2 inhibition in low copy number HER2 amplified CRC remains uncertain. Patient-derived cancer organoids (PDCOs) allow an ex vivo method to assess treatment sensitivity. We examined treatment sensitivity of a HER2 amplified PDCO at baseline and following resistance to panitumumab and trastuzumab. Methods: Following IRB-approval, fresh CRC tissue was cultured to maturation. After expansion, subcultures were treated with stepwise (20%) increase to physiologic Cmax of panitumumab (230ug/mL) and trastuzumab (180ug/mL). Threshold for escalation was median relative growth of +20% at 96h. Sensitivity was assessed on primary culture (RC1), panitumumab resistance (RC1-P) and trastuzumab resistance (RC1-T) using 96h of physiologic Cmax panitumumab, trastuzumab, and combination trastuzumab/pertuzumab. Individual sphere response was assessed for change in mean NADH autofluorescence intensity and ratio of NADH/FAD signal. Response was assessed at 96h in comparison to control using effect size of Glass’s Delta (GΔ). Results: Molecular profiling revealed HER2 copy number of 14 with no concurrent alterations in RAS, RAF, or PIK3CA. Time to resistance was similar between panitumumab (55 days) and trastuzumab (51 days). RC1 had baseline growth (+116%) which was reduced with single agent panitumumab (+17%, GΔ=1.40) with intermediate sensitivity to trastuzumab (+48%, GΔ=0.95) and trastuzumab/pertuzumab (46%, GΔ=0.99). Normalized NADH/FAD ratio revealed significant metabolic response to panitumumab (-20%, GΔ=0.66) and trastuzumab/pertuzumab (-35%, GΔ=1.16) with insignificant effect of single agent trastuzumab (-14%, GΔ=0.46). Following resistance to panitumumab, RC1-P had persistent growth with trastuzumab (+68%) which improved in combination trastuzumab/pertuzumab (+34%, GΔ=1.16). Following resistance to trastuzumab, RC1-T was insensitive to EGFRi with panitumumab including persistent growth (+58%, GΔ=0.70) and unchanged metabolism (+2%, GΔ=-0.10). Conclusions: Therapeutic dose escalation in a single PDCO of HER2 amplified CRC suggests improved sensitivity to EGFRi and dual HER2 targeting with trastuzumab/pertuzumab. Resistance to EGFRi resulted in persistent sensitivity to dual HER2 inhibition using trastuzumab/pertuzumab, however resistance to single agent trastuzumab. Resistance to trastuzumab resulted in future insensitivity to EGFRi. Molecular profiling at resistance revealed no pathologic alterations in EGFR or ERBB2 signaling, with ongoing analysis of transcriptional changes by RNAseq.

The aim of this study was to demonstrate the correlation between human epidermal growth factor receptor 2 (HER2) overexpression and some poor prognosis factors in patients affected by ductal carcinoma in situ (DCIS). We evaluated 48 cases of DCIS, divided into two groups according to HER2 amplification status. Nuclear grade and "cancerization of lobules" were determined within primary DCIS and Ki67, estrogen receptor (ER), PR, and HER2 expression was established using immunohistochemistry. The histopathological variables in HER2-positive and in HER2-negative patients were compared to determine the recurrence risk. We also considered the median age at the time of surgery according to HER2 status. There were 11 recurrences (23%), 6 DCIS (55%), and 5 invasive cancer (45%). In an 8-year-long median follow-up, we hypothesized high risk of recurrence in HER2-positive DCIS. Patients with HER2-positive DCIS were younger than HER2-negative ones (p = 0.002). HER2-positive DCIS was also related to histopathological predictors of recurrence such as high nuclear grade (p < 0.001), high Ki67 expression (p = 0.003), low ER and PgR levels (p < 0.001), and the presence of "cancerization of lobules" (p < 0.049). Our trial suggests that HER2 amplification in primary DCIS is identified more frequently in younger patients and hypothesizes high risk of recurrence in HER2-positive DCIS related to histopathological predictors of overall relapse as high nuclear grade, high Ki67 expression, low ER and PgR levels, and the presence of "cancerization of lobules." In HER2-positive DCIS, other variables of recurrence risk are compared to HER2-negative lesions, without statistical significance. Our results show that HER2 testing might suggest clinicians the optimal treatment of patients with DCIS.

In metastatic colorectal cancer, the optimization of upfront treatment and the continuum of care based on patients’ exposure to multiple treatment lines have reached a plateau of efficacy. Therefore, a paradigm shift is ongoing towards precision medicine and personalized treatments based on the specific molecular features of the disease. In this perspective, the improved knowledge of disease biology coming from the lab has prompted a rapid translation from bench to bedside of newer targeted strategies. Here, we focus on the most promising biomarkers already included or close to adoption in daily clinical practice. In particular, evidence about the potential roles of BRAF mutation, HER2 amplification, MGMT methylation, microsatellite instability, and ALK, ROS and NTRK1–3 rearrangements as positive predictors of benefit from biological agents is reviewed and discussed.

// Qian-Qian Xu 1 , Bo Pan 1 , Chang-Jun Wang 1 , Yi-Dong Zhou 1 , Feng Mao 1 , Yan Lin 1 , Jing-Hong Guan 1 , Song-Jie Shen 1 , Xiao-Hui Zhang 1 , Ya-Li Xu 1 , Ying Zhong 1 , Xue-Jing Wang 1 , Yan-Na Zhang 1 , Qiang Sun 1 1 Department of Breast Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P. R. China Correspondence to: Qiang Sun, email: sunqiangpumc@126.com Keywords: HER2-positive breast cancer, HER2 amplification, prognosis, trastuzumab-based treatment, adjuvant setting Received: June 21, 2016 Accepted: August 17, 2016 Published: August 23, 2016 ABSTRACT Background: Trastuzumab-based therapy is a standard, targeted treatment for HER2-positive breast cancer in the adjuvant setting. However, patients do not benefit equally from it and the association between HER2 amplification level and patients’ survival remains controversial. A systematic review and meta-analysis was conducted by incorporating all available evidence to evaluate the association between disease free survival (DFS) and HER2 amplification level. Results: Three cohort studies involving 1360 HER2-positive breast cancer patients stratified by HER2 amplification magnitude were eligible for meta-analysis. The combined HRs for DFS were 1.05 (95% CI: 0.80−1.36, p = 0.74) and 0.97 (95% CI: 0.73−1.29, p = 0.83) for HER2 gene copy number (GCN) and HER2/CEP 17 ratio. No evidence of heterogeneity or public bias was found. Methods: Databases including PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials (CENTRAL), were searched for eligible literature. HER2 amplification level was evaluated by fluorescence in situ hybridization (FISH) in terms of gene copy number (GCN) and HER2/CEP17 ratio. Hazard ratios (HRs) for DFS with 95% confidence interval (CI) according to the amplification level of HER2 were extracted. The outcomes were synthesized based on a fixed-effects model. Conclusions: HER2 amplification level is not a prognostic factor for HER2-positive breast cancer with trastuzumab-based targeted therapy in the clinical adjuvant setting.