Lung Adenocarcinomas with HER2-Activating Mutations Are Associated with Distinct Clinical Features and HER2/EGFR Copy Number Gains

Molecular landscape of ERBB2 alterations in 3000 advanced NSCLC patients

ERBB2 (HER2) represents a newly recognized actionable oncogenic driver in non-small cell lung cancer (NSCLC), with approved targeted therapy available. Understanding the landscape of ERBB2 alterations and co-occurring mutations is essential for guiding treatment decisions. We conducted an analysis involving 3000 NSCLC patients with all types of ERBB2 alterations, drawn from two extensive retrospective cohorts: 1281 from Geneplus (Chinese) and 1719 from Guardant360 (the United States, US). The incidence of all types of ERBB2 alterations was found to be 5.6% in the Chinese group and 5.2% in the US group. In both cohorts, among oncogenic alterations of ERBB2, exon 20 insertion Y772_A775dupYVMA was the most frequent alteration (58% vs 41.6% in the Chinese vs the US), followed by G776delinsVC/LC/VV/IC (10.7% vs 9.7%), and S310X (10.5% vs 15.4%). EGFR ex20 insertions were identified in the A767-V774 region, whereas ERBB2 ex20 insertions were observed in the Y772-P780 region. Notably, EGFR ex20 insertions exhibited greater insertion diversity. Clinical characteristics of EGFR and ERBB2 ex20 NSCLC were similar, characterized by low tumor mutation burden (TMB), a predominant never-smoker population, and a majority of lung adenocarcinoma cases.

Long term survival achieved through combination of almonertinib and pyrotinib in EGFR-mutant/HER2-amplified advanced NSCLC patient: a case report and literature review

Backgroud

Human epithelial growth factor receptor 2 (HER2) amplification is an important mechanism of acquired resistance to anti-epidermal growth factor receptor (EGFR) therapy in non-small cell lung cancer (NSCLC) patients. For patients with both EGFR mutation and HER2 amplification, there is currently no unified standard treatment, and further exploration is needed on how to choose the therapy.

Methods and results

A female NSCLC patient developed bone and brain metastases 14 and 42 months after radical surgery, respectively. The second genetic sequencing detected EGFR L858R mutation and HER2 amplification, and therefore initiated treatment with almonertinib and pyrotinib. The patient achieved partial remission and did not show any further progression during the follow-up period.

Conclusion

For NSCLC patients with both EGFR mutation and HER2 amplification, the combination of almonertinib and pyrotinib is a valuable therapy that can continuously reduce tumor burden and achieve long-term survival.

Exploring the correlation between HER2 alterations and 18F-FDG PET/CT metabolic parameters and their prognostic value in EGFR-negative non-small-cell lung cancer patients

PURPOSE

Our study intended to explore the correlation between HER2 alterations and 18F-FDG PET/CT metabolic parameters and their prognostic value in EGFR-negative non-small-cell lung cancer (NSCLC) patients detected by next-generation sequencing (NGS).

METHODS

NGS assay was performed in 1737 NSCLC patients, a total of 88 HER2 alterations and 176 negative HER2 with EGFR-negative patients were randomly selected for this study.

RESULTS

When the HER2 status with EGFR-negative group was analyzed, multivariate analysis showed that smoking status, primary tumor SUVmax (pSUVmax) < 13.03 and stage were the independent deterministic factors of HER2 alterations. Multivariate cox regression analysis revealed that HER2 status, age, smoking status and stage were independent risk factors for overall survival (OS) in EGFR-negative NSCLC patients with different HER2 status. When the HER2 alterations group was separately analyzed, multivariate analysis demonstrated that low pSUVmax < 15.32 and histology were the independent deterministic factors of HER2 mutation. Multivariate cox regression analysis revealed that pSUVmax, smoking status, nodal involvement and treatment methods were independent risk factors for OS in EGFR-negative NSCLC patients with HER2 alterations.

CONCLUSION

The study revealed that low pSUVmax was associated with HER2 alterations in EGFR-negative NSCLC patients, moreover HER2 mutation and HER2 amplification exhibited distinct 18F-FDG metabolic and clinical characteristics. Furthermore, it explored the prognostic value of HER2 alterations and 18F-FDG PET/CT metabolic parameters of pSUVmax in EGFR-negative NSCLC patients.

The expression of HER2/neu in patients with lung cancer and its associated factors

BACKGROUND AND OBJECTIVES

Lung cancer is the most common cause of cancer-related death worldwide in both sexes. Evidence suggests the role of genetic factors in lung cancer. Studying of such factors can help understand the cancer prognosis. Overexpression of the human epidermal growth factor receptor-2 (HER2/neu) protein is considered an important prognostic factor in breast cancer, but its role has not been confirmed in lung cancer. Therefore, the present study aimed to investigate the role of its expression in patients with lung cancer.

MATERIALS AND METHODS

In this cross-sectional study, patients aged >18 years who were referred to Afzalipoor Hospital, Kerman, Iran, from 2016 to 2017, and were diagnosed with lung cancer were enrolled into the study if they had a pathological sample of their cancerous lung. Their demographics were recorded, and the sample was sectioned and stained to measure HER2/neu gene expression according to DAKO instructions using heat-induced antigen retrieval (HIER) enzyme marker.

RESULTS

The samples of 100 patients with lung cancer were evaluated (84% men and 16% women) with a mean age of 61.34 years (standard deviation of 12.51 years). HER2/neu expression was significantly associated with the type of cancer and was highest in adenocarcinoma and zero in small cell carcinoma (P < 0.001), but not with patients' sex, age, smoking status and family history of cancer (P > 0.05).

CONCLUSION

These results emphasized the overexpression of HER2/neu in different types of lung cancer, which can be used further for therapeutic purposes. The results showed that HER2/neu was overexpressed not only in adenocarcinoma but also in other types, like squamous cell carcinoma. Therefore, all subtypes of non-small cell lung carcinoma should be considered for anti-HER2 therapies, and further research is required for small cell lung carcinoma.

KRAS mutated Non-Small Lung Carcinoma: A Real World Context from the Indian subcontinent

BACKGROUND

KRAS, although a common variant of occurrence (~20% of non-small-cell lung carcinoma [NSCLC]) has been untargetable, owing to the molecular structure which inherently prevents drug binding. KRAS mutations in NSCLC are associated with distinct clinical profiles including smokers and mucinous histology. KRAS G12C mutations account for ~40% KRAS altered NSCLC, but NSCLC being a geographically diverse disease, the features may be distinct in this part of the world. This is a single-center experience of KRAS-mutated NSCLC including clinical, imaging, pathologic features, and treatment patterns and outcomes.

METHODS

This is a single-center retrospective study of KRAS-mutated NSCLC. The clinicopathological features and outcomes were retrieved and collated from the medical record archives of the hospital.

RESULTS

Fifty (30.6%) patients with advanced-stage NSCLC with alterations in the KRAS gene were enrolled in the 163 patients who were tested for KRAS alterations. The median age was 61 years. Molecular detection revealed three main types of KRAS mutations viz-a-vis: G12C in 17 (34%), G12V in 9 (18%), and G12D in 6 (12%) patients. Comparing G12C versus the non-G12C mutated cases, co-mutations were common in the non-G12C subgroup (p < 0.05). Among the 36, who were treated at our center, all received chemotherapy as the first line with a median progression-free survival (PFS)of 5.4 months. The PFS of G12C was higher than the non-G12C subgroup (6.4 vs 3.8 months).

CONCLUSION

This is the largest single-center experience from the Indian subcontinent for KRAS-mutated NSCLC with distinct clinical features. It highlights the unmet need for G12C inhibitors in our country, where prevalence is equivalent to the West.

Phosphoproteome of signaling by ErbB2 in ovarian cancer cells

The gene for receptor tyrosine kinase ErbB2 is amplified in breast and ovarian tumours. The linear pathway by which signals are transduced through ErbB2 are well known. However, second generation questions that address spatial aspects of signaling remain. To address this, we have undertaken a mass spectrometry approach to identify phosphoproteins specific for ErbB2 using the inhibitors Lapatinib and CP724714 in ovarian cancer cells. The ErbB2 specific proteins identified in SKOV-3 cells were Myristoylated alanine-rich C-kinase substrate, Protein capicua homolog, Protein peptidyl isomerase G, Protein PRRC2C, Chromobox homolog1 and PRP4 homolog. We have evaluated three phosphoproteins PKM2, Aldose reductase and MARCKS in SKOV-3 cells. We observed that PKM2 was phosphorylated by EGF but was not inhibited by Lapatinib and CP724714. The activity of aldose reductase in reducing NADPH as a substrate was significantly higher in EGF stimulated cells which was inhibited by Lapatinib and CP724714 but not by Geftinib (EGFR inhibitor). MARCKS was phosphorylated on stimulation of SKOV-3 cells with EGF that was inhibited by Lapatinib and CP724714 which was dependent on the kinase activity of ErbB2. These results have identified phosphoproteins that are specific to ErbB2 which have not been previously reported and sets the basis for future experiments.

Consensus for HER2 alterations testing in non-small-cell lung cancer

Human epidermal growth factor receptor 2 (HER2) is a transmembrane glycoprotein receptor with intracellular tyrosine kinase activity. Its alterations, including mutation, amplification and overexpression, could result in oncogenic potential and have been detected in many cancers such as non-small-cell lung cancer (NSCLC). Such alterations are, in general, considered markers of poor prognosis. Anti-HER2 antibody-drug conjugates, e.g. trastuzumab deruxtecan (T-DXd, DS-8201) and disitamab vedotin (RC48), were recently approved for HER2-positive breast and gastric cancers. Meanwhile, several HER2-targeted drugs, such as T-DXd, neratinib, afatinib, poziotinib and pyrotinib, have been evaluated in patients with advanced NSCLC, with several of them demonstrating clinical benefit. Therefore, identifying HER2 alterations is pivotal for NSCLC patients to benefit from these targeted therapies. Recent guidelines on HER2 testing were developed for breast and gastric cancer, however, and have not been fully established for NSCLC. The expert group here reached a consensus on HER2 alteration testing in NSCLC with the focus on clinicopathologic characteristics, therapies, detection methods and diagnostic criteria for HER2-altered NSCLC patients. We hope this consensus could improve the clinical management of NSCLC patients with HER2 alterations.

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Human epidermal growth factor receptor 2 (HER2) alterations lead to poor prognosis in non-small-cell lung cancer (NSCLC).

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Identifying HER2 alterations is pivotal to guide the anti-HER2-targeted therapies in NSCLC.

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The requirements for HER2 mutation, amplification or expression testing are distinct in NSCLC.

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This consensus fills the gap in the criteria for HER2 alteration testing in NSCLC.

Epstein-Barr Virus Infection in Lung Cancer: Insights and Perspectives

Lung cancer (LC) is the leading cause of cancer death worldwide. Tobacco smoke is the most frequent risk factor etiologically associated with LC, although exposures to other environmental factors such as arsenic, radon or asbestos are also involved. Additionally, the involvement of some viral infections such as high-risk human papillomaviruses (HR-HPVs), Merkel cell polyomavirus (MCPyV), Jaagsiekte Sheep Retrovirus (JSRV), John Cunningham Virus (JCV), and Epstein-Barr virus (EBV) has been suggested in LC, though an etiological relationship has not yet been established. EBV is a ubiquitous gamma herpesvirus causing persistent infections and some lymphoid and epithelial tumors. Since EBV is heterogeneously detected in LCs from different parts of the world, in this review we address the epidemiological and experimental evidence of a potential role of EBV. Considering this evidence, we propose mechanisms potentially involved in EBV-associated lung carcinogenesis. Additional studies are warranted to dissect the role of EBV in this very frequent malignancy.

The Effects of HER2 Alterations in EGFR Mutant Non-small Cell Lung Cancer

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.

Progress in Treatment of Non-Small Cell Lung Cancer Harboring HER2 Aberrations

Epidermal growth factor receptor 2 (HER2/ErbB2/neu), a member of ErbB receptor tyrosine kinase family, forms homo- or heterodimers with ErbB1 (HER1/EGFR), ErbB3 (HER3), or ErbB4 (HER4), to activate signal transduction pathways and promote proliferation, differentiation and tumorigenesis. Preliminary clinical trials of monoclonal antibodies, antibody conjugates and small-molecule tyrosine kinase inhibitors targeting HER2 have indicated that HER2 is a potential therapeutic target in non-small cell lung cancer (NSCLC). HER2 aberrations in NSCLC patients mainly include mutation, amplification, and overexpression. While there are significant differences in the outcome of NSCLC with these HER2 changes, no consensus has been reached for the incidence, detection method and targeted treatments for the three types of HER2 aberration. HER2 mutation is generally considered to have more clinical relevance and response to HER2-targeted therapies. In this review, we discuss HER2 alterations in NSCLC, including diagnostic challenges and treatment strategies particular to the HER2 mutation.

Beyond RAS and BRAF: HER2, a New Actionable Oncotarget in Advanced Colorectal Cancer

The human epidermal growth factor receptor 2 (HER2) is a well-established oncogenic driver and a successful therapeutic target in several malignancies, such as breast and gastric cancers. HER2 alterations, including amplification and somatic mutations, have also been detected in a small but not negligible subset of patients affected by advanced colorectal cancer (aCRC). However, to date, there are no available oncotargets in this malignancy beyond RAS and BRAF that are available. Here we present an overview on the present predictive and prognostic role of HER2 expression in aCRC, as well as on its consequent potential therapeutic implications from preclinical investigations towards ongoing trials testing anti-HER2 agents in aCRC. While HER2's role as a molecular predictive biomarker for anti-EGFR therapies in CRC is recognized, HER2 prognostic value remains controversial. Moreover, thanks to the impressive and growing body of clinical evidence, HER2 is strongly emerging as a new potential actionable oncotarget in aCRC. In conclusion, in the foreseeable future, HER2-targeted therapeutic strategies may integrate the algorithm of aCRC treatment towards an increasingly tailored therapeutic approach to this disease.

Next-Generation Kinase Inhibitors Targeting Specific Biomarkers in Non-Small Cell Lung Cancer (NSCLC): A Recent Overview

Lung cancer causes many deaths globally. Mutations in regulatory genes, irregularities in specific signal transduction events, or alterations of signalling pathways are observed in cases of non-small cell lung cancer (NSCLC). Over the past two decades, a few kinases have been identified, validated, and studied as biomarkers for NSCLC. Among them, EGFR, ALK, ROS1, MET, RET, NTRK, and BRAF are regarded as targetable biomarkers to cure and/or control the disease. In recent years, the US Food and Drug Administration (FDA) approved more than 15 kinase inhibitors targeting these NSCLC biomarkers. The kinase inhibitors significantly improved the progression-free survival (PFS) of NSCLC patients. Challenges still remain for metastatic diseases and advanced NSCLC cases. New discoveries of potent kinase inhibitors and rapid development of modern medical technologies will help to control NSCLC cases. This article provides an overview of the discoveries of various types of kinase inhibitors against NSCLC, along with medicinal chemistry aspects and related developments in next-generation kinase inhibitors that have been reported in recent years.

Treatment of Rare Mutations in Patients with Lung Cancer

Lung cancer is a worldwide prevalent malignancy. This disease has a low survival rate due to diagnosis at a late stage challenged by the involvement of metastatic sites. Non-small-cell lung cancer (NSCLC) is presented in 85% of cases. The last decade has experienced substantial advancements in scientific research, leading to a novel targeted therapeutic approach. The newly developed pharmaceutical agents are aimed towards specific mutations, detected in individual patients inflicted by lung cancer. These drugs have longer and improved response rates compared to traditional chemotherapy. Recent studies were able to identify rare mutations found in pulmonary tumors. Among the gene alterations detected were mesenchymal epithelial transition factor (MET), human epidermal growth factor 2 (HER2), B-type Raf kinase (BRAF), c-ROS proto-oncogene (ROS1), rearranged during transfection (RET) and neurotrophic tyrosine kinase (NTRK). Ongoing clinical trials are gaining insight onto possible first and second lines of medical treatment options intended to enable progression-free survival to lung cancer patients.

Targeting HER2 Alterations in Non–Small-Cell Lung Cancer: A Comprehensive Review

PURPOSE

HER2 is a critical gene that drives various solid tumors in addition to those of breast cancer. For example, HER2 plays a role in non–small-cell lung cancer (NSCLC). Overexpression, amplification, and point mutations in HER2 have been described in patients with NSCLC; however, the potential roles of these alterations remain unclear.

METHODS

We summarize the evidence regarding the distinct impacts of different HER2 aberrations on antitumor agents. Also, we update the therapeutic efficacy of HER2-targeted agents, including anti-HER2 antibodies, antibody-drug conjugates, and small-molecule tyrosine kinase inhibitors, tested in HER2-aberrant NSCLC.

RESULTS

Although these drugs are not yet standard treatments, certain patients may benefit from these therapies. In this review, we aim to provide an improved understanding of HER2 aberrations in NSCLC, including NSCLC biology and the impacts of each aberration on prognosis and standard treatment. We also highlight the potential of novel anti-HER2 therapies approved by regulatory bodies and those in clinical development.

CONCLUSION

Compared with HER2 amplification or overexpression, HER2 mutations, especially HER2 exon 20 mutations, are emerging as the most clear targetable driver for HER2-directed therapies in lung cancer. De novo and inducible HER2 pathway activation need to be differentially managed. Further investigations with new strategies are needed.

Status of 10 targeted genes of non-small cell lung cancer in eastern China: A study of 884 patients based on NGS in a single institution

BACKGROUND

The status of targeted genes and the association between targeted genes and clinicopathological features in Chinese lung cancer patients remains to be elucidated.

METHODS

The status of 10 targeted genes was evaluated by next-generation sequencing (NGS) in 884 non-small cell lung cancer (NSCLC) patients. The relationship between gene alterations and clinicopathological characters was analyzed.

RESULTS

Overall, 684 (77.4%) patients harbored gene alterations, and EGFR (510, 57.7%) was found to be the most common type of mutation followed by KRAS (91, 10.3%), HER2 (38, 4.3%), PIK3CA (32, 3.6%), ALK (21, 2.4%), BRAF (10, 1.1%), ROS1 (5, 0.6%), RET (5, 0.6%), MET (4, 0.5%) and NRAS (1, 0.1%). Gene alterations were more frequent in females, non-smokers and adenocarcinoma (P < 0.001). EGFR mutations were associated with women, non-smokers, normal level of serum tumor markers, and adenocarcinoma (P < 0.001). Patients without lymph node metastasis (P = 0.012), or early stage disease (P < 0.001) exhibited a higher EGFR mutation rate. KRAS mutations tended to arise in men (P < 0.001), smokers (P < 0.001) and patients with higher levels of serum tumor markers (P = 0.048). A mucus-producing component was associated with KRAS (P < 0.001), ROS1 (P = 0.033) and ALK (P < 0.001) alterations. ALK and ROS1 rearrangements were more frequent in micropapillary structures (P = 0.004, P = 0.012). BRAF mutation was associated with advanced disease patients and micropapillary structure (P < 0.001). PIK3CA mutation was more likely to be found in elderly patients (P = 0.014). Some patients had synchronous gene alterations, including EGFR/PIK3CA, EGFR/HER2, HER2/KRAS, EGFR/KRAS, EGFR/ROS1, EGFR/NRAS, KRAS/PIK3CA, KRAS/PIK3CA/HER2.

CONCLUSIONS

Most patients had at least one genetic alteration, and individual patients harbored synchronous mutation. Each gene alteration had unique clinicopathological characteristics.

KEY POINTS

SIGNIFICANT FINDINGS OF THE STUDY: This study revealed the frequency and distribution of 10 targeted gene abnormalities and their association with clinicopathological parameters of Chinese non-small cell lung cancer (NSCLC) patients in eastern China.

WHAT THIS STUDY ADDS

Some rare synchronous mutations were detected in our study by next-generation sequencing (NGS).

An ErbB2 splice variant lacking exon 16 drives lung carcinoma

Lung cancer causes more deaths annually than any other malignancy. A subset of non-small cell lung cancer (NSCLC) is driven by amplification and overexpression or activating mutation of the receptor tyrosine kinase (RTK) ERBB2 In some contexts, notably breast cancer, alternative splicing of ERBB2 causes skipping of exon 16, leading to the expression of an oncogenic ERBB2 isoform (ERBB2ΔEx16) that forms constitutively active homodimers. However, the broader implications of ERBB2 alternative splicing in human cancers have not been explored. Here, we have used genomic and transcriptomic analysis to identify elevated ERBB2ΔEx16 expression in a subset of NSCLC cases, as well as splicing site mutations facilitating exon 16 skipping and deletions of exon 16 in a subset of these lung tumors and in a number of other carcinomas. Supporting the potential of ERBB2ΔEx16 as a lung cancer driver, its expression transformed immortalized lung epithelial cells while a transgenic model featuring inducible ERBB2ΔEx16 specifically in the lung epithelium rapidly developed lung adenocarcinomas following transgene induction. Collectively, these observations indicate that ERBB2ΔEx16 is a lung cancer oncogene with potential clinical importance for a proportion of patients.

Non-amplification genetic alterations of HER2 gene in non-small cell lung carcinoma

AIMS

The present study investigated the incidence and spectrum of human epidermal growth factor receptor 2 (HER2) mutations, associated clinicopathological characteristics and the co-occurrence of HER2 gene amplification in the HER2 gene mutated cases in non-small cell lung cancer (NSCLC).

METHODS

All patients with advanced lung adenocarcinoma (LUAD) who underwent broad genomic profiling by next generation sequencing (NGS) from 2015 to 2019 were included in the study. HER2 gene amplification was checked in all the HER2 gene mutated cases. Tumour tissues of all the mutated cases were examined by fluorescent in situ hybridisation (FISH).

RESULTS

Fifty-four (37.2%) out of the 145 cases harboured tier 1 driver mutations comprising EGFR in 22.1%, ALK rearrangements in 7.6% cases, ROS1 rearrangements and BRAF ^V600E in 3.5% cases each, and NTRK fusion in 0.7% cases. Nine (6.2%) cases exhibited a significant genetic alteration in HER2 gene (tiers 2 and 3) on NGS. The most common alteration was exon 20 insertion of amino acid sequence AYVM in five cases (p.E770_A771insAYVM) followed by insertion of YVMA (p.A771_Y772insYVMA) in one case, insGSP (p.V777_G778insGSP) in one case and two missense mutations: p.G776C and p.QA795C (novel variant). The median copy number of the HER2 gene was 3.21 while on FISH, the median HER2/CEP17 ratio was 2.0.

CONCLUSIONS

There is a relatively higher occurrence of HER2 exon 20 mutations as primary oncogenic driver in NSCLC especially LUAD. Our cohort has demonstrated (p.E770_A771insAYVM) as the strikingly dominant insertion mutation against the most often globally reported (p.A771_Y772insYVMA).

Impact of concurrent genomic alterations in epidermal growth factor receptor (EGFR)-mutated lung cancer

Comprehensive characterization of the genomic landscape of epidermal growth factor receptor (EGFR)-mutated lung cancers have identified patterns of secondary mutations beyond the primary oncogenic EGFR mutation. These include concurrent pathogenic alterations affecting p53 (60–65%), RTKs (5–10%), PIK3CA/KRAS (3–23%), Wnt (5–10%), and cell cycle (7–25%) pathways as well as transcription factors such as MYC and NKX2-1 (10–15%). The majority of these co-occurring alterations were detected or enriched in samples collected from patients at resistance to tyrosine kinase inhibitor (TKI) treatment, indicating a potential functional role in driving resistance to therapy. Of note, these co-occurring tumor genomic alterations are not necessarily mutually exclusive, and evidence suggests that multiple clonal and sub-clonal cancer cell populations can co-exist and contribute to EGFR TKI resistance. Computational tools aimed to classify, track and predict the evolution of cancer clonal populations during therapy are being investigated in pre-clinical models to guide the selection of combination therapy switching strategies that may delay the development of treatment resistance. Here we review the most frequently identified tumor genomic alterations that co-occur with mutated EGFR and the evidence that these alterations effect responsiveness to EGFR TKI treatment.

The force of HER2 - A druggable target in NSCLC?

Since several years targeted therapy has been part of treatment in NSCLC in subsets of patients with specific genetic alterations. One of these alterations involves HER2, a member of the ERBB family of tyrosine kinase receptors. Despite that HER2 alterations in NSCLC have been studied for years, there is still no consensus about subgroup definitions. In this review HER2 alterations in NSCLC are discussed, including diagnostic challenges and treatment strategies. Three principal mechanisms of HER2 alterations can be identified: HER2 protein overexpression, HER2 gene amplification and HER2 gene mutations. There are several methods for the detection of HER2 "positivity" in NSCLC, but no gold standard has been established. Laboratory methods for assessment of HER2 positivity in NSCLC include immunohistochemistry (IHC) for protein overexpression and fluorescent in situ hybridization (FISH) and next generation sequencing (NGS) for genetic alterations. Many trials testing HER2 targeted therapy in HER2 altered NSCLC has not lead to a renewed standard of care for this group of patients. Therefore, today the (re)search on how to analyse, define and treat HER2 alterations in NSCLC continues. Still there is no consensus about HER2 subgroup definitions and results of the many trials studying possible treatment strategies are inconclusive. Future research should focus on the most important missing link, whether all HER2 alterations are relevant oncogenic drivers and whether it should be considered as a therapeutic target in NSCLC.

Targeting non-small cell lung cancer: driver mutation beyond epidermal growth factor mutation and anaplastic lymphoma kinase fusion

The identification of driver mutations in epidermal growth factor receptor, anaplastic lymphoma kinase, the BRAF and ROS1 genes and subsequent successful clinical development of kinase inhibitors not only significantly improves clinical outcomes but also facilitates the discovery of other novel driver mutations in non-small cell lung cancer. These driver mutations can be categorized into mutations in or near the kinase domain, gene amplification or fusion. In this review, BRAF V600E, EGFR and HER-2 exon 20 mutation, FGFR1-4, K-RAS, MET, neuregulin-1, NRTK, PI3K/AKT/mTOR, RET and ROS1 gene aberration and their therapeutics will be discussed.

Clinical Characteristics and Outcomes of Non-small Cell Lung Cancer Patients with HER2 Alterations in Korea

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.

Afatinib in patients with metastatic or recurrent HER2-mutant lung cancers: a retrospective international multicentre study

INTRODUCTION

HER2 mutations occur in 1-3% of lung adenocarcinomas. With increasing use of next-generation sequencing at diagnosis, more patients with HER2-mutant tumours present for treatment. Few data are available to describe the clinical course and outcomes of these patients when treated with afatinib, a pan-HER inhibitor.

METHODS

We identified patients with metastatic or recurrent HER2-mutant lung adenocarcinomas treated with afatinib among seven institutions across Europe, Australia, and North America between 2009 and 2017. We determined the partial response rate to afatinib, types of HER2 mutations, duration of response, time on treatment, and survival.

RESULTS

We collected information on 27 patients with stage IV or recurrent HER2-mutant lung adenocarcinomas treated with afatinib. Of 23 patients evaluable for response, three partial responses were noted (13%, 95% confidence interval [CI] 4-33%). In addition, 57% of patients (13/23) had stable disease, and 30% (7/23) had progressive disease. We documented partial responses in patients with HER2 exon 20 insertions, including two with YVMA insertion and one with VAG insertion. Two patients with partial responses were previously treated with trastuzumab and pertuzumab. Median duration of response to afatinib was 6 months (range 5-10); median time on treatment was 3 months (range 1-30) and median overall survival from the date of diagnosis of metastatic or recurrent disease was 23 months (95% CI 18-53 months).

CONCLUSIONS

Afatinib is modestly active in patients with HER2-mutant lung adenocarcinomas, including responses after progression on prior HER2-targeted therapies. However, investigations into the biology of HER2-mutant lung adenocarcinomas and development of better HER2-directed therapies are warranted.

Differential Subcellular Localization Regulates Oncogenic Signaling by ROS1 Kinase Fusion Proteins

Chromosomal rearrangements involving receptor tyrosine kinases (RTK) are a clinically relevant oncogenic mechanism in human cancers. These chimeric oncoproteins often contain the C-terminal kinase domain of the RTK joined in cis to various N-terminal, nonkinase fusion partners. The functional role of the N-terminal fusion partner in RTK fusion oncoproteins is poorly understood. Here, we show that distinct N-terminal fusion partners drive differential subcellular localization, which imparts distinct cell signaling and oncogenic properties of different, clinically relevant ROS1 RTK fusion oncoproteins. SDC4-ROS1 and SLC34A2-ROS1 fusion oncoproteins resided on endosomes and activated the MAPK pathway. CD74-ROS1 variants that localized instead to the endoplasmic reticulum (ER) showed compromised activation of MAPK. Forced relocalization of CD74-ROS1 from the ER to endosomes restored MAPK signaling. ROS1 fusion oncoproteins that better activate MAPK formed more aggressive tumors. Thus, differential subcellular localization controlled by the N-terminal fusion partner regulates the oncogenic mechanisms and output of certain RTK fusion oncoproteins. SIGNIFICANCE: ROS1 fusion oncoproteins exhibit differential activation of MAPK signaling according to subcellular localization, with ROS1 fusions localized to endosomes, the strongest activators of MAPK signaling.

Clinical benefit from afatinib in an advanced squamous cell lung carcinoma patient harboring HER2 S310Y mutation: a case report

Background

HER2 mutations are identified in approximately 2% of non-small-cell lung cancer (NSCLC) cases and are predominantly observed in non-smokers, females, and adenocarcinoma patients. Although afatinib is recommended for treating NSCLC patients with HER2 mutation, the therapy is most efficacious in patients harboring HER2 exon 20 insertions, especially the in-frame insertion YVMA. Research on the treatment of the extracellular domain mutation is relatively rare.

Case presentation

We discuss a 76-year-old Chinese man with a heavy-smoking history who was diagnosed with stage IV squamous cell lung carcinoma. First-line treatment with the angiogenesis inhibitor endostar and systemic chemotherapy with docetaxel plus cisplatin were administered, but the patient ceased treatment because of chemotherapy-induced adverse events. Based on the test result from an amplification refractory mutation system PCR, EGFR-inhibitor icotinib was prescribed, but there was still no evidence of a response. Then, next-generation sequencing identified an HER2 S310Y mutation, and afatinib therapy resulted in a gradual, but substantial reduction in tumor size.

Conclusion

This is the first published case report of the successful management of HER2 S310Y mutation squamous cell lung carcinoma with afatinib. Considering the fact that this rare HER2 mutation clinically benefited from afatinib treatment, attention should be paid to the incidence of HER2 in NSCLC patients with inconsistent histological characteristics compared with those previous published. With the guidance of a precise diagnosis, we should realize the significance of other HER2 gene mutations and next-generation sequencing as a diagnostic method.

Advances in HER2-Targeted Therapy: Novel Agents and Opportunities Beyond Breast and Gastric Cancer

The introduction of HER2-targeted therapy for breast and gastric patients with ERBB2 (HER2) amplification/overexpression has led to dramatic improvements in oncologic outcomes. In the past 20 years, five HER2-targeted therapies have been FDA approved, with four approved in the past 8 years. HER2-targeted therapy similarly was found to improve outcomes in HER2-positive gastric cancer. Over the past decade, with the introduction of next-generation sequencing into clinical practice, our understanding of HER2 biology has dramatically improved. We have recognized that HER2 amplification is not limited to breast and gastric cancer but is also found in a variety of tumor types such as colon cancer, bladder cancer, and biliary cancer. Furthermore, HER2-targeted therapy has signal of activity in several tumor types. In addition to HER2 amplification and overexpression, there is also increased recognition of activating HER2 mutations and their potential therapeutic relevance. Furthermore, there is a rapidly growing number of new therapeutics targeting HER2 including small-molecule inhibitors, antibody-drug conjugates, and bispecific antibodies. Taken together, an increasing number of patients are likely to benefit from approved and emerging HER2-targeted therapies.

Diagnostic and Predictive Immunohistochemistry for Non-Small Cell Lung Carcinomas

Non-small cell lung carcinoma (NSCLC) accounts for significant morbidity and mortality worldwide, with most patients diagnosed at advanced stages and managed increasingly with targeted therapies and immunotherapy. In this review, we discuss diagnostic and predictive immunohistochemical markers in NSCLC, one of the most common tumors encountered in surgical pathology. We highlight 2 emerging diagnostic markers: nuclear protein in testis (NUT) for NUT carcinoma; SMARCA4 for SMARCA4-deficient thoracic tumors. Given their highly aggressive behavior, proper recognition facilitates optimal management. For patients with advanced NSCLCs, we discuss the utility and limitations of immunohistochemistry (IHC) for the "must-test" predictive biomarkers: anaplastic lymphoma kinase, ROS1, programmed cell death protein 1, and epidermal growth factor receptor. IHC using mutant-specific BRAF V600E, RET, pan-TRK, and LKB1 antibodies can be orthogonal tools for screening or confirmation of molecular events. ERBB2 and MET alterations include both activating mutations and gene amplifications, detection of which relies on molecular methods with a minimal role for IHC in NSCLC. IHC sits at the intersection of an integrated surgical pathology and molecular diagnostic practice, serves as a powerful functional surrogate for molecular testing, and is an indispensable tool of precision medicine in the care of lung cancer patients.

Clinical characterization of ERBB2 exon 20 insertions and heterogeneity of outcomes responding to afatinib in Chinese lung cancer patients

Purpose

ERBB2 exon 20 insertions (20ins) have been identified as oncogenic drivers in lung cancers. Lung cancer patients with 20ins benefit from afatinib. However, response heterogeneity was observed in patients harboring different 20ins subtypes. In this study, we interrogated clinical characteristics in ERBB2-mutated Chinese lung cancer and investigated the clinical outcomes of specific ERBB2 20ins in response to afatinib.

Experimental design

In this study, we retrospectively collected genomic profiling data of 7,520 lung cancer patients sequenced using next-generation sequencing in a Clinical Laboratory Improvement Amendments-certified laboratory. We analyzed the clinical and molecular features of patients harboring ERBB2 20ins and evaluated clinical outcomes of 19 patients with clinical records after afatinib treatment.

Results

ERBB2 20ins were identified in 2.27% (171/7,520) of this lung cancer cohort. It occurred with a high proportion in females with adenocarcinoma histology. ERBB2 20ins was mutually exclusive with other well-established lung cancer oncogenic driver mutations. The most frequently appearing subtype was Y772_A775dup (69.6%) and several novel insertion subtypes were also identified. The correlations of specific 20ins subtypes and survival were investigated. The presence of a glycine at position 778 in ERBB2 was suggested to be a common feature of drug sensitivity mutations. Patients harboring G778_P780dup (G778) subtype achieved longer median progression-free survival and median overall survival than other 20ins (non-G778) subtypes (median progression-free survival, 10 vs 3.3 months, P=0.32; median overall survival, 19.7 vs 7 months, P=0.16). Moreover, we presented the first clinical case of a lung squamous cell carcinoma patient harboring ERBB2 20ins who achieved partial response to afatinib.

Conclusion

This study interrogated the characteristics of ERBB2 20ins in a large cohort from single ethnicity and demonstrated the response heterogeneity to afatinib among different ERBB2 20ins subtypes. Further studies in a larger cohort are needed to investigate the underlying molecular mechanisms and clinical response of different ERBB2 20ins subtypes.

A systematic understanding of signaling by ErbB2 in cancer using phosphoproteomics

ErbB2 is an important receptor tyrosine kinase and a member of the ErbB family. Although it does not have a specific ligand, it transmits signals downstream by heterodimerization with other receptors in the family. It plays a major role in a variety of cellular responses like proliferation, differentiation, and adhesion. ErbB2 is amplified at the DNA level in breast cancer (20%–30%) and gastric cancer (10%–20%), and trastuzumab is effective as a therapeutic antibody. This review is a critical analysis of the currently published data on the signaling pathways of ErbB2 and the interacting proteins. It also focuses on the techniques that are currently available to evaluate the entire phosphoproteome following activation of ErbB2. Identification of new and relevant phosphoproteins can not only serve as new therapeutic targets but also as a surrogate marker in patients to assess the activity of compounds that inhibit ErbB2. Overall, such analysis will improve understanding of signaling by ErbB2.

Efficacy generated by afatinib in a lung adenocarcinoma patient harboring HER2 S310Y mutation

Afatinib exhibits therapeutic efficacy for lung adenocarcinoma patients harboring HER2 exon 20 insertions. HER2 S310Y single site substitution was discovered in recent years and afatinib efficacy for adenocarcinoma patients harboring S310Y mutation has not been reported. We presented a case of a 41-year-old male patient with lung adenocarcinoma harboring the HER2 S310Y mutation obtained clinical response to the treatment of afatinib, an oral HER family blocker. After the treatment of afatinib, the patient achieved partial response (PR) in chest lesions and almost complete response (CR) in intracranial lesions. He experienced progressive disease (PD) with liver metastasis and achieved a progression-free survival (PFS) of 5 months. He continually treated with afatinib after CT guided percutaneous radiofrequency ablation to eradicate the hepatic tumor cells and achieved stable disease (SD). In this study, we reported the first clinical evidence of efficacy generated by afatinib, the irreversible HER family inhibitor, targeting HER2 S310Y single site mutation in lung adenocarcinoma.

Whole-exome sequencing identifies key mutated genes in T790M wildtype/cMET-unamplified lung adenocarcinoma with acquired resistance to first-generation EGFR tyrosine kinase inhibitors

PURPOSE

Lung cancer is the leading cause of cancer-related death worldwide. Lung adenocarcinoma harboring EGFR-activating mutations will inevitably acquire resistance to first-generation EGFR tyrosine kinase inhibitors (TKIs). EGFR T790M mutation and cMET amplification are common mechanisms. Further study is needed to explore unknown genomic alterations contributing to drug resistance.

METHODS

Tumor and blood samples from 69 stage IIIB-IV NSCLC patients defined as acquired resistance to first-generation EGFR TKIs (gefitinib, erlotinib or ecotinib) were collected. The cobas^® and Droplet digital PCR (ddPCR) were used to detect T790M mutations in tumor samples and plasma ctDNA. cMET amplification was evaluated by fluorescence in situ hybridization (FISH). Exome sequencing was performed in four T790M wildtype/cMET-unamplified samples.

RESULTS

The overall T790M-positive rate was 52.2% considering all testing methods. Out of 21 samples in which tumor re-biopsy was performed, 14 were T790M positive (66.7%). cMET amplification was identified in three out of seven T790M-negative samples. Exome sequencing in four T790M wildtype/cMET-unamplified samples and paired white blood cells identified a cohort of candidate key mutated genes including BRAF, FGFR1, PAK1, PCNT, PEBP4 and SOX3.

CONCLUSIONS

EGFR T790M mutation and cMET amplification are main mechanisms leading to EGFR TKI resistance in lung adenocarcinoma. These key mutated genes identified in the present study would need further validation in large number of patients.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

- In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

- To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

- The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

- Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

- The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes ( ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes (ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology

CONTEXT

In 2013, an evidence-based guideline was published by the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology to set standards for the molecular analysis of lung cancers to guide treatment decisions with targeted inhibitors. New evidence has prompted an evaluation of additional laboratory technologies, targetable genes, patient populations, and tumor types for testing.

OBJECTIVE

To systematically review and update the 2013 guideline to affirm its validity; to assess the evidence of new genetic discoveries, technologies, and therapies; and to issue an evidence-based update.

DESIGN

The College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology convened an expert panel to develop an evidence-based guideline to help define the key questions and literature search terms, review abstracts and full articles, and draft recommendations.

RESULTS

Eighteen new recommendations were drafted. The panel also updated 3 recommendations from the 2013 guideline.

CONCLUSIONS

The 2013 guideline was largely reaffirmed with updated recommendations to allow testing of cytology samples, require improved assay sensitivity, and recommend against the use of immunohistochemistry for EGFR testing. Key new recommendations include ROS1 testing for all adenocarcinoma patients; the inclusion of additional genes (ERBB2, MET, BRAF, KRAS, and RET) for laboratories that perform next-generation sequencing panels; immunohistochemistry as an alternative to fluorescence in situ hybridization for ALK and/or ROS1 testing; use of 5% sensitivity assays for EGFR T790M mutations in patients with secondary resistance to EGFR inhibitors; and the use of cell-free DNA to "rule in" targetable mutations when tissue is limited or hard to obtain.

Targeting Novel but Less Common Driver Mutations and Chromosomal Translocations in Advanced Non-Small Cell Lung Cancer

Discovery of the epidermal growth factor receptor gene mutation and the anaplastic lymphoma kinase chromosomal translocation in non-small cell lung cancer has prompted efforts around the world to identify many less common targetable oncogenic drivers. Such concerted efforts have been variably successful in both non-squamous and squamous cell carcinomas of the lung. Some of the targeted therapies for these oncogenic drivers have received regulatory approval for clinical use, while others have modest clinical benefit. In this mini-review, several of these targets will be reviewed.

The frequency and clinical impact of HER2 alterations in lung adenocarcinoma

Human epidermal growth factor receptor 2 (HER2 or ErbB2) can be overexpressed, amplified and/or mutated in malignant tumors, and is a candidate for therapeutic targeting. However, molecular associations and clinical significances of these alterations were controversial in lung cancer. In this study, we investigated the frequency and clinicopathological significance of HER2 dysregulation in patients with lung adenocarcinoma. HER2 protein overexpression, gene amplification, and gene mutation were evaluated by immunohistochemistry (IHC), silver in situ hybridization, and direct sequencing, respectively. The H-scoring method and American Society of Clinical Oncology/College of American Pathologists breast cancer guidelines were used to interpret IHC results. Genetic analyses of EGFR and KRAS mutations, and of ALK and ROS1 rearrangements, were also performed. Of the 321 adenocarcinoma patients identified, HER2 overexpression (H-score ≥200) and gene amplification were found in 6 (1.9%) and 46 (14.3%), respectively. HER2 overexpression was correlated with papillary predominant histology; furthermore, it indicated poor overall survival and was an independent prognostic factor. HER2 amplification was associated with pleural invasion and showed a tendency towards shorter overall and disease-free survival. High-level gene amplification (HER2/CEP17 ratio ≥5 or copy number ≥10) was a poor prognostic factor for disease-free survival. HER2 mutations were detected in 6.7% (7 of 104) of driver oncogene-negative adenocarcinomas. Our study suggests that HER2 overexpression or amplification is a poor prognostic factor in lung adenocarcinoma, although the frequency of such events is low. Since molecular targeted agents are being tested in clinical trials, awareness of the specific HER2 status can influence the prognostic stratification and treatment of patients with molecularly defined subsets of lung adenocarcinoma.

Cancer genomics guide clinical practice in personalized medicine

Targeted therapies have revolutionized the treatment of many cancers. Widely developed over the last decade, this new concept of precision medicine relies on the use of genomic technologies to analyze tumor samples in order to identify actionable targets and biomarkers of resistance. The goal is to optimize treatment by identifying which therapeutic approach is best for each patient, i.e. the treatment that is effective, has minimal adverse effects, and avoids unnecessary intervention and cost. The purpose of this review is to highlight, using a few seminal examples of therapeutic targets, the important contribution of appropriate analysis of key oncogenes or driver genes in making clinical decisions. Cancer genomics is now an indispensable part of clinical management. Furthermore, the development of next generation sequencing (NGS) will enable exploration of more and more genes of interest, leading to new treatment options for personalized medicine.

Epidemiological study of HER-2 mutations among EGFR wild-type lung adenocarcinoma patients in China

Background

Human epidermal growth factor receptor (HER)-2 is a driver gene in non-small cell lung cancer (NSCLC). The present study evaluated the mutation rate of HER-2 within the wild-type epidermal growth factor receptor (EGFR) lung adenocarcinoma population in China.

Methods

Formalin-fixed, paraffin-embedded samples from 456 patients with wild-type EGFR lung adenocarcinoma were analyzed for HER-2 mutations by amplification-refractory mutation system (ARMS), and HER-2 protein expression was evaluated by immunohistochemistry. All samples positive for HER-2 mutation underwent direct sequencing for further verification.

Results

HER-2 mutation was detected in 22/456 cases (4.8 %); the rate was 6.7 % among 331 triple-negative samples (i.e., wild-type EGFR, anaplastic lymphoma kinase, and ROS proto-oncogene 1). Direct sequencing confirmed that the results were consistent with those obtained by ARMS analysis in 19 cases. The positive rate was 15.4 % by immunohistochemical analysis of HER-2 expression; this was not correlated with mutation rate. HER-2 mutation and positivity were not correlated with gender, age, smoking status, disease stage, or histological subtype. The 22 cases of HER-2 mutations occurred only in acinar (36.4 %), papillary (36.4 %), minimally invasive (13.6 %), solid (9.2 %), and invasive mucinous (4.5 %) subtypes. Disease-free and overall survival were not associated with HER-2 mutation or HER-2 protein overexpression.

Conclusion

The HER-2 mutation rate was 4.8 % among EGFR wild-type lung adenocarcinoma patients in China, and 6.7 % among driver genes, triple-negative lung adenocarcinoma. The incidence of HER-2 mutation varied among different lung adenocarcinoma subtypes, occurring mainly in acinar and papillary predominant subtypes. 15.4 % of EGFR wild-type lung adenocarcinoma patients showed HER-2 protein overexpression, but this was not correlated to HER-2 mutation. Existing follow-up data did not show a correlation between HER-2 mutation with DFS or OS.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2875-z) contains supplementary material, which is available to authorized users.

Comprehensive Genomic Profiling Facilitates Implementation of the National Comprehensive Cancer Network Guidelines for Lung Cancer Biomarker Testing and Identifies Patients Who May Benefit From Enrollment in Mechanism-Driven Clinical Trials

BACKGROUND

The National Comprehensive Cancer Network (NCCN) guidelines for patients with metastatic non-small cell lung cancer (NSCLC) recommend testing for EGFR, BRAF, ERBB2, and MET mutations; ALK, ROS1, and RET rearrangements; and MET amplification. We investigated the feasibility and utility of comprehensive genomic profiling (CGP), a hybrid capture-based next-generation sequencing (NGS) test, in clinical practice.

METHODS

CGP was performed to a mean coverage depth of 576× on 6,832 consecutive cases of NSCLC (2012-2015). Genomic alterations (GAs) (point mutations, small indels, copy number changes, and rearrangements) involving EGFR, ALK, BRAF, ERBB2, MET, ROS1, RET, and KRAS were recorded. We also evaluated lung adenocarcinoma (AD) cases without GAs, involving these eight genes.

RESULTS

The median age of the patients was 64 years (range: 13-88 years) and 53% were female. Among the patients studied, 4,876 (71%) harbored at least one GA involving EGFR (20%), ALK (4.1%), BRAF (5.7%), ERBB2 (6.0%), MET (5.6%), ROS1 (1.5%), RET (2.4%), or KRAS (32%). In the remaining cohort of lung AD without these known drivers, 273 cancer-related genes were altered in at least 0.1% of cases, including STK11 (21%), NF1 (13%), MYC (9.8%), RICTOR (6.4%), PIK3CA (5.4%), CDK4 (4.3%), CCND1 (4.0%), BRCA2 (2.5%), NRAS (2.3%), BRCA1 (1.7%), MAP2K1 (1.2%), HRAS (0.7%), NTRK1 (0.7%), and NTRK3 (0.2%).

CONCLUSION

CGP is practical and facilitates implementation of the NCCN guidelines for NSCLC by enabling simultaneous detection of GAs involving all seven driver oncogenes and KRAS. Furthermore, without additional tissue use or cost, CGP identifies patients with "pan-negative" lung AD who may benefit from enrollment in mechanism-driven clinical trials.

IMPLICATIONS FOR PRACTICE

National Comprehensive Cancer Network guidelines for patients with metastatic non-small cell lung cancer (NSCLC) recommend testing for several genomic alterations (GAs). The feasibility and utility of comprehensive genomic profiling were studied in NSCLC and in lung adenocarcinoma (AD) without GAs. Of patients with NSCLC, 71% harbored at least one GA to a gene listed in the guidelines or KRAS; 273 cancer-related genes were altered in at least 0.1% of the AD cases. Although logistical and administrative hurdles limit the widespread use of next-generation sequencing, the data confirm the feasibility and potential utility of comprehensive genomic profiling in clinical practice.

[Role of HER2 in NSCLC]

过去几年中, 随着分子靶向药物的引入, 非小细胞肺癌(non-small cell lung cancer, NSCLC)的药物治疗策略发生了巨大变化, 向基于组织学和分子水平的治疗手段转变。表皮生长因子受体(epidermal growth factor receptor, EGFR)突变、Kirsten鼠肉瘤(Kirsten rat sarcoma, KRAS)癌基因突变、间变淋巴瘤激酶(anaplastic lymphoma kinase, ALK)重排等的发现, 影响着NSCLC治疗的发展。最近, 对人表皮生长因子受体2(human epidermal growth factor receptor 2, HER2)研究重燃兴趣, 这一基因改变与NSCLC对不同酪氨酸激酶抑制剂(tyrosine kinase inhibitors, TKIs)的敏感性相关, 其具有可能的预测作用, HER2扩增可能是EGFR突变肿瘤对EGFR-TKIs获得性耐药的机制之一。其次, HER2突变可能阐明一条新的靶向治疗NSCLC的策略。本文将对NSCLC中HER2异常调节发挥的作用做一简要介绍。

Clinicopathologic Characteristics of Patients with HER2 Insertions in Non-small Cell Lung Cancer

BACKGROUND

The human epidermal growth factor receptor-2 (HER2) genes have been described in a subset of non-small cell lung cancer (NSCLC). To help identify and treat these patients, we investigated the frequency, clinicopathologic characteristics, and clinical outcomes of patients who had NSCLC with or without HER2 insertions.

METHODS

The mutational status of the HER2 (exons 19-20) gene was assessed in a cohort of 1875 patients with NSCLC. All patients were also analyzed for mutations in EGFR, KRAS, BRAF, ALK, RET, and ROS1. Clinical characteristics, including age, sex, smoking status, stage, histology, tumor size, differentiation, overall survival, and relapse-free survival, were collected.

RESULTS

Among 1875 NSCLCs examined, 35 (1.9 %) were HER2 insertion. Compared with the HER2 insertion-negative group, patients with HER2 insertions were more likely to be never smokers (97.1 %, 34/35 patients, P < 0.001), significantly associated with female (91.4 %, 32/35 patients, P < 0.001), adenocarcinoma (91.4 %, 32/35 patients, P = 0.01), and with a tendency to be no more than 60 years of age (71.4 %, 25/35 patients, P = 0.051).

CONCLUSIONS

HER2 insertion could define a distinct subset of NSCLC, which had a higher prevalence among females, nonsmokers, and adenocarcinoma. HER2 should be in the clinical genotyping of lung cancer, so patients may benefit from HER2-targeted therapy.

Multi-institutional Oncogenic Driver Mutation Analysis in Lung Adenocarcinoma: The Lung Cancer Mutation Consortium Experience

INTRODUCTION

Molecular genetic analyses of lung adenocarcinoma have recently become standard of care for treatment selection. The Lung Cancer Mutation Consortium was formed to enable collaborative multi-institutional analyses of 10 potential oncogenic driver mutations. Technical aspects of testing and clinicopathologic correlations are presented.

METHODS

Mutation testing in at least one of the eight genes (epidermal growth factor receptor [EGFR], KRAS, ERBB2, AKT1, BRAF, MEK1, NRAS, and PIK3CA) using SNaPshot, mass spectrometry, Sanger sequencing+/- peptide nucleic acid and/or sizing assays, along with anaplastic lymphoma kinase (ALK) and/or MET fluorescence in situ hybridization, were performed in six labs on 1007 patients from 14 institutions.

RESULTS

In all, 1007 specimens had mutation analysis performed, and 733 specimens had all 10 genes analyzed. Mutation identification rates did not vary by analytic method. Biopsy and cytology specimens were inadequate for testing in 26% and 35% of cases compared with 5% of surgical specimens. Among the 1007 cases with mutation analysis performed, EGFR, KRAS, ALK, and ERBB2 alterations were detected in 22%, 25%, 8.5%, and 2.4% of cases, respectively. EGFR mutations were highly associated with female sex, Asian race, and never-smoking status; and less strongly associated with stage IV disease, presence of bone metastases, and absence of adrenal metastases. ALK rearrangements were strongly associated with never-smoking status and more weakly associated with presence of liver metastases. ERBB2 mutations were strongly associated with Asian race and never-smoking status. Two mutations were seen in 2.7% of samples, all but one of which involved one or more of PIK3CA, ALK, or MET.

CONCLUSION

Multi-institutional molecular analysis across multiple platforms, sample types, and institutions can yield consistent results and novel clinicopathological observations.

HER2 Amplification and HER2 Mutation Are Distinct Molecular Targets in Lung Cancers

INTRODUCTION

Human epidermal growth factor receptor 2 gene (HER2 [also known as ERBB2]) alterations have been identified as oncogenic drivers and potential therapeutic targets in lung cancers. The molecular associations of HER2 gene amplification, mutation, and HER2 protein overexpression in lung cancers have not been distinctly defined. To explore these associations, Memorial Sloan Kettering Cancer Center and the University of Colorado combined their data on HER2 alterations in lung cancers.

METHODS

Tumor specimens from 175 patients with lung adenocarcinomas and no prior targeted therapy were evaluated for the presence of HER2 amplification and mutation and HER2 protein overexpression. Amplification was assessed by fluorescence in situ hybridization (FISH) and defined as an HER2-to-chromosome enumeration probe 17 ratio of at least 2.0. Mutation was assessed by fragment analysis, mass spectrometry genotyping, and Sanger sequencing. Overexpression was assessed by immunohistochemical (IHC) staining. The frequencies of HER2 amplification and mutation and HER2 overexpression were calculated and their overlap examined.

RESULTS

HER2 amplification was detected by FISH in 5 of 175 cases (3%). HER2 mutation was detected in 4 of 148 specimens (3%), including three identical 12-base pair insertions (p.A775_G776insYVMA) and a 9-base pair insertion, all in exon 20. None of the HER2-mutant cases was amplified. HER2 overexpression (2+ or 3+) on IHC staining was not detected in the 25 specimens available for testing, and negative IHC staining correlated with the negative results according to FISH.

CONCLUSIONS

HER2 mutations are not associated with HER2 amplification, thus suggesting a distinct entity and therapeutic target. HER2-positive lung cancer may not be an adequate term, and patient cohorts for the study of HER2-targeted agents should be defined by the specific HER2 alteration present.

NSCLC and HER2: between lights and shadows

The therapeutic landscape of non-small-cell lung cancer (NSCLC) has dramatically changed in the last few years with the introduction of molecularly targeted agents, leading to unprecedented results in lung tumors with a paradigmatic shift from a "one size fits all" approach to an histologic and molecular-based approach. The discovery of epidermal growth factor receptor (EGFR) mutations in NSCLC in 2004 and the marked response to the EGFR tyrosine kinase inhibitor gefitinib, in a small subset of patients harboring these genetic abnormalities, stimulated the study of other kinase mutants involvement in NSCLC. The incredible story of ALK rearranged tumors, with the rapid Food and Drug Administration approval of Crizotinib after only 4 years from the discovery of EML4-ALK translocation in NSCLC, has profoundly influenced the concept of drug development in NSCLC, paving the way to a novel series of molecularly selected studies with specific inhibitors. The identification of these oncogenic drivers has dramatically changed the genetic landscape of NSCLC moving away from the old concept of a large indistinct histological entity to a combination of rare clinically relevant molecular subsets. Recently, a renewed interest has been emerging on the human epidermal growth factor-2 (HER2) pathway. Genetic aberrations of this signaling pathway have been reported over time to be associated in NSCLC with different sensitivity to the EGFR tyrosine kinase inhibitors, to have a possible prognostic role and more recently HER2 amplification has been emerged as a possible mechanism in EGFR-mutated tumors of acquired resistance to the EGFR tyrosine kinase inhibitors. In addition, dysregulation of the HER2 pathway, in particular HER2 mutations (mostly, in-frame exon 20 insertions), may represent a possible novel therapeutic target in NSCLC, paving the way for a new generation of targeted agents in NSCLC. Since anecdotal case reports of clinical activity of anti-HER2 agents in NSCLC patients with HER2 mutations, several targeted agents have been evaluated in HER2-mutated patients, generating a growing interest upon this oncogenic driver, leading to the design of molecularly selected trials with anti-HER2 compounds and the rediscover of hastily thrown out drugs, such as neratinib. The aim of this article is to provide an overview of the role of HER2 dysregulation in NSCLCs, trying to throw a light not only on the strengths but also the weaknesses of the studies conducted so far. It is a long way to the clinical implementation of these biomarkers and probably the increasing use of next generation sequencing techniques, the creation of large multi-institutional molecular testing platforms and the design of rationally based trials can get closer personalized medicine in NSCLC.

A systematic analysis of the resistance and sensitivity of HER2YVMA receptor tyrosine kinase mutant to tyrosine kinase inhibitors in HER2-positive lung cancer

Human epidermal growth factor receptor 2 (HER2) has become a well-established target for the treatment of HER2-positive lung cancer. However, a frequently observed in-frame mutation that inserts amino acid quadruplex Tyr776-Val777-Met778-Ala779 at G776 (G776(YVMA)) in HER2 kinase domain can cause drug resistance and sensitivity, largely limiting the application of reversible tyrosine kinase inhibitors in lung cancer therapy. A systematic investigation of the intermolecular interactions between the HER2(YVMA) mutant and clinical small-molecule inhibitors would help to establish a complete picture of drug response to HER2 G776(YVMA) insertion in lung cancer, and to design new tyrosine kinase inhibitors with high potency and selectivity to target the lung cancer-related HER2(YVMA) mutant. Here, we combined homology modeling, ligand grafting, structure minimization, molecular simulation and binding affinity analysis to profile a number of tyrosine kinase inhibitors against the G776(YVMA) insertion in HER2. It is found that the insertion is far away from HER2 active pocket and thus cannot contact inhibitor ligand directly. However, the insertion is expected to induce marked allosteric effect on some regions around the pocket, including A-loop and hinges connecting between the N- and C-lobes of HER2 kinase domain, which may exert indirect influence to inhibitor binding. Most investigated inhibitors exhibit weak binding strength to both wild-type and mutant HER2, which can be attributed to steric hindrance that impairs ligand compatibility with HER2 active pocket. However, the cognate inhibitor lapatinib and the non-cognate inhibitor bosutinib were predicted to have low affinity for wild-type HER2 but high affinity for HER2(YVMA) mutant, which was confirmed by subsequent kinase assay experiments; the inhibitory potencies of bosutinib against wild-type and mutant HER2 were determined to be IC(50) > 1000 and =27 nM, respectively, suggesting that the bosutinib might be exploited as a selective inhibitor for mutant over wild-type HER2. Structural examination revealed that formation of additional non-bonded interactions such as hydrogen bonds and hydrophobic contacts with HER2 A-loop region due to G776(YVMA) insertion is the primary factor to improve bosutinib affinity upon the mutation.

The minority report: targeting the rare oncogenes in NSCLC

OPINION STATEMENT

Lung cancer is still responsible for the highest number of cancer deaths worldwide. Despite this fact, significant progress has been made in the treatment of non-small cell lung cancer (NSCLC). Specifically, efforts to identify and treat genetic alterations (gene mutations, gene fusions, gene amplification events, etc.) that result in oncogenic drivers are now standard of care (EGFR and ALK) or an intense area of research. The most prevalent oncogenic drivers have likely already been identified; thus, there is now a focus on subgroups of tumors with less common genetic alterations. Interestingly, as we explore these less common mutations, we are discovering that many occur across other tumor types (i.e., non-lung cancer), further justifying their study. Furthermore, many studies have demonstrated that by searching broadly for multiple genetic alterations in large subsets of patients they are able to identify potentially targetable alterations in the majority of patients. Although individually, the rare oncogenic drivers subgroups may seem to occur too infrequently to justify their exploration, the fact that the majority of patients with NSCLC harbor a potentially actionable driver mutation within their tumors and the fact that different types of cancers often have the same oncogenic driver justifies this approach.