High Prevalence of Concomitant Oncogene Mutations in Prospectively Identified Patients with ROS1-Positive Metastatic Lung Cancer

Lung adenocarcinoma patients with ROS1-rearranged tumors by sex and smoking intensity

Background

ROS1 rearrangements (ROS1+) define a distinct molecular subset of lung adenocarcinomas. ROS1 + tumors are known to occur more in never-smokers, but the frequency and outcome of ROS1 positivity by sex and smoking intensity are not clearly documented.

Patients and methods

This patient cohort study included all never- (<100 cigarettes lifetime) and light- (100 cigarettes-20 pack-years) smokers, and a sample of heavy-smokers. ROS1 + rates by sex and smoking intensity were compared within and beyond our study. Survival outcomes were analyzed using Kaplan-Meier curves and Cox proportional hazards models.

Results

Of the 571 total patients, ROS1 + was detected in 24 (4.2%): 6.4% in men and 3.0% in women; 5.1% in never-, 5.7% in light-, and 1.8% in heavy-smokers (P=0.05). Among the 209 stage IIIB-IV patients, men had much higher ROS1 + rate (11.1%) not only than women (1.7%, P=0.004) in our study, but also than men (0.4%-1.8%) in 8 published studies (Ps = 0.0019-0.0001). ROS1+ rates were similar between never- (9.3%) and light-smokers (8.1%) and significantly lower in heavy-smokers (1.2%, P=0.017), a finding confirmed by 6 published studies (Ps = 0.041-0.0001). Overall survival of ROS1 + patients were significantly better than the ROS1- (P=0.023) mainly due to targeted therapy. Among patients who exhibited resistance to crizotinib, follow-up treatment of entrectinib and lorlatinib showed remarkable survival benefits.

Conclusions

The ROS1 + rates were higher in men than in women, and similar in never- and light-smokers, more pronounced in stage IIIB-IV patients. Newer-generation ALK/ROS1-targeted drugs showed efficacy in a cohort of crizotinib resistant ROS1 + patients. These results, when validated, could assist efficiently accruing ROS1 + patients.

Simultaneous inhibition of FAK and ROS1 synergistically repressed triple-negative breast cancer by upregulating p53 signalling

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype lacking effective targeted therapies, necessitating innovative treatment approaches. While targeting ROS proto-oncogene 1 (ROS1) with crizotinib has shown promise, resistance remains a limitation. Recent evidence links focal adhesion kinase (FAK) to drug resistance, prompting our study to assess the combined impact of FAK inhibitor IN10018 and crizotinib in TNBC and elucidate the underlying mechanisms.

METHODS

We employed the Timer database to analyze FAK and ROS1 mRNA levels in TNBC and adjacent normal tissues. Furthermore, we investigated the correlation between FAK, ROS1, and TNBC clinical prognosis using the GSE database. We conducted various in vitro assays, including cell viability, colony formation, flow cytometry, EdU assays, and western blotting. Additionally, TNBC xenograft and human TNBC organoid models were established to assess the combined therapy's efficacy. To comprehensively understand the synergistic anti-tumor mechanisms, we utilized multiple techniques, such as RNA sequencing, immunofluorescence, cell flow cytometry, C11-BODIPY staining, MDA assay, and GSH assay.

RESULTS

The Timer database revealed higher levels of FAK and ROS1 in TNBC tissues compared to normal tissues. Analysis of GEO databases indicated that patients with high FAK and ROS1 expression had the poorest prognosis. Western blotting confirmed increased p-FAK expression in crizotinib-resistant TNBC cells. In vitro experiments showed that the combination therapy down-regulated cyclin B1, p-Cdc2, and Bcl2 while up-regulating BAX, cleaved-Caspase-3, cleaved-Caspase-9, and cleaved PARP. In TNBC xenograft models, the tumor volume in the combination therapy group was 73% smaller compared to the control group (p < 0.0001). Additionally, the combination therapy resulted in a 70% reduction in cell viability in human TNBC organoid models (p < 0.0001). RNA sequencing analysis of TNBC cells and xenograft tumor tissues highlighted enrichment in oxidative stress, glutathione metabolism, and p53 pathways. The combined group displayed a fivefold rise in the reactive oxygen species level, a 69% decrease in the GSH/GSSG ratio, and a sixfold increase in the lipid peroxidation in comparison to the control group. Western blotting demonstrated p53 upregulation and SCL7A11 and GPX4 downregulation in the combination group. The addition of a p53 inhibitor reversed these effects.

CONCLUSION

Our study demonstrates that the combination of IN10018 and crizotinib shows synergistic antitumor effects in TNBC. Mechanistically, this combination inhibits cell proliferation, enhances apoptosis, and induces ferroptosis, which is associated with increased p53 levels.

Clinical significance of TP53 alterations in advanced NSCLC patients treated with EGFR, ALK and ROS1 tyrosine kinase inhibitors: An update

 The development of targeted therapies for non-small cell lung cancer (NSCLC), such as the epidermal growth factor receptor (EGFR), anaplastic lymphoma receptor tyrosine kinase (ALK), and ROS proto-oncogene 1 (ROS1), has improved patients' prognosis and significantly extended progression-free survival. However, it remains unclear why some patients do not benefit from the treatment as much or have a rapid disease progression. It is considered that, apart from the oncogenic driver gene, molecular alterations in a number of caretaker and gatekeeper genes significantly impact the efficacy of targeted therapies. The tumor protein 53 (TP53) gene is one of the most frequently mutated genes in NSCLC. To date, numerous studies have investigated the influence of various TP53 alterations on patient prognosis and responsiveness to therapies targeting EGFR, ALK, or ROS1. This review focuses on the latest data concerning the role of TP53 alterations as prognostic and/or predictive biomarkers for EGFR, ALK, and ROS1 tyrosine kinase inhibitors (TKIs) in advanced NSCLC patients. Since the presence of TP53 mutations in NSCLC has been linked to its decreased responsiveness to EGFR, ALK, and ROS1 targeted therapy in most of the referenced studies, the review also discusses the impact of TP53 mutations on treatment resistance. It seems plausible that assessing the TP53 mutation status could aid in patient stratification for optimal clinical decision-making. However, drawing meaningful conclusions about the clinical value of the TP53 co-mutations in EGFR-, ALK- or ROS1-positive NSCLC is hampered mainly by an insufficient knowledge regarding the functional consequences of the TP53 alterations. The integration of next-generation sequencing into the routine molecular diagnostics of cancer patients will facilitate the detection and identification of targetable genetic alterations along with co-occurring TP53 variants. This advancement holds the potential to accelerate understanding of the biological and clinical role of p53 in targeted therapies for NSCLC.

Progress of non-small-cell lung cancer with ROS1 rearrangement

ROS1 rearrangement is found in 0.9%-2.6% of people with non-small-cell lung cancers (NSCLCs). Tyrosine kinase inhibitors (TKIs) target ROS1 and can block tumor growth and provide clinical benefits to patients. This review summarizes the current knowledge on ROS1 rearrangements in NSCLCs, including the mechanisms of ROS1 oncogenicity, epidemiology of ROS1-positive tumors, methods for detecting rearrangements, molecular characteristics, therapeutic agents, and mechanisms of drug resistance.

Therapeutical Options in ROS1-Rearranged Advanced Non Small Cell Lung Cancer

ROS proto-oncogene 1 (ROS1) rearrangements occur in 0.9-2.6% of patients with non small cell lung cancer (NSCLC), conferring sensitivity to treatment with specific tyrosine-kinase inhibitors (TKI). Crizotinib, a first-generation TKI, was the first target-therapy approved for the first-line treatment of ROS1-positive NSCLC. Recently, entrectinib, a multitarget inhibitor with an anti-ROS1 activity 40 times more potent than crizotinib and better activity on the central nervous system (CNS), received approval for treatment-naive patients. After a median time-to-progression of 5.5-20 months, resistance mechanisms can occur, leading to tumor progression. Therefore, newer generation TKI with greater potency and brain penetration have been developed and are currently under investigation. This review summarizes the current knowledge on clinicopathological characteristics of ROS1-positive NSCLC and its therapeutic options.

[New update to the guidelines on testing predictive biomarkers in non-small-cell lung cancer: a National Consensus of the Spanish Society of Pathology and the Spanish Society of Medical Oncology]

Non-small cell lung cancer (NSCLC) presents the greatest number of identified therapeutic targets, some of which have therapeutic utility. Currently, detecting EGFR, BRAF, KRAS and MET mutations, ALK, ROS1, NTRK and RET translocations, and PD-L1 expression in these patients is considered essential. The use of next-generation sequencing (NGS) facilitates precise molecular diagnosis and allows the detection of other emerging mutations, such as the HER2 mutation and predictive biomarkers for immunotherapy responses. In this consensus, a group of experts in the diagnosis and treatment of NSCLC selected by the Spanish Society of Pathology (SEAP) and the Spanish Society of Medical Oncology (SEOM) have evaluated currently available information and propose a series of recommendations to optimize the detection and use of biomarkers in daily clinical practice.

Evolution of acquired resistance in a ROS1+ KRAS G12C+ NSCLC through the MAPK pathway

Patients with metastatic NSCLC bearing a ROS1 gene fusion usually experience prolonged disease control with ROS1-targeting tyrosine kinase inhibitors (TKI), but significant clinical heterogeneity exists in part due to the presence of co-occurring genomic alterations. Here, we report on a patient with metastatic NSCLC with a concurrent ROS1 fusion and KRAS p.G12C mutation at diagnosis who experienced a short duration of disease control on entrectinib, a ROS1 TKI. At progression, the patient continued entrectinib and started sotorasib, a small molecule inhibitor of KRAS p.G12C. A patient-derived cell line generated at progression on entrectinib demonstrated improved TKI responsiveness when treated with entrectinib and sotorasib. Cell-line growth dependence on both ROS1 and KRAS p.G12C was further reflected in the distinct downstream signaling pathways activated by each driver. Clinical benefit was not observed with combined therapy of entrectinib and sotorasib possibly related to an evolving KRAS p.G12C amplification identified on repeated molecular testing. This case supports the need for broad molecular profiling in patients with metastatic NSCLC for potential therapeutic and prognostic information.

Concurrent classic driver oncogenes mutation with ROS1 rearrangement predicts superior clinical outcome in NSCLC patients

BACKGROUND

There is high mortality rate and poor prognosis in lung cancer, especially non-small-cell lung cancer (NSCLC). Recent study showed that concurrent classic driver oncogene mutation with ROS1 rearrangement was found in NSCLC patients. However, whether this would affect the development and prognosis of NSCLC is still unclear.

OBJECTIVE

To explore the clinical characteristics and prognosis of NSCLC patients harboring concurrent classic driver oncogene mutation with ROS1 rearrangement.

METHODS

A retrospective study was conducted on 220 patients diagnosed with NSCLC. All samples were screened for EGFR and KRAS using amplification-refractory mutation system assay, and for ALK, ROS1 using RT-PCR. The clinical characteristics and clinical outcomes of concurrent gene alterations with ROS1 rearrangement were analyzed.

RESULTS

In 220 patients, 12 (5.45%) were ROS1 rearrangement, who tend to be younger, non-smokers. The mutation rates of EGFR, KRAS, ALK and ROS1 in NSCLC were 28.64%, 1.82%, 3.64% and 5.45%, respectively. ROS1 rearrangement was identified to co-occur in 5 (2.27%) NSCLC patients. ROS1/EGFR co-alterations were found in 3.17% of NSCLC patients, 16.67% of ROS1-positive NSCLC patients. Concomitant ROS1/ALK rearrangement constituted 37.50% in ALK-positive patients, and 25.00% in ROS1-positive patients. SDC4-ROS1 was the most common fusion partner in concurrent ROS1 rearrangement patients. The median overall survival of NSCLC with concurrent ROS1 rearrangement group and single ROS1 rearrangement group were 25 months and 14 months.

CONCLUSION

Concurrent driver oncogenes mutation with ROS1 rearrangement defines a unique subgroup of NSCLC. Patients with concomitant ROS1 rearrangement might have a better prognosis.

New update to the guidelines on testing predictive biomarkers in non-small-cell lung cancer: a National Consensus of the Spanish Society of Pathology and the Spanish Society of Medical Oncology

Non-small cell lung cancer (NSCLC) presents the greatest number of identified therapeutic targets, some of which have therapeutic utility. Currently, detecting EGFR, BRAF, KRAS and MET mutations, ALK, ROS1, NTRK and RET translocations, and PD-L1 expression in these patients is considered essential. The use of next-generation sequencing facilitates precise molecular diagnosis and allows the detection of other emerging mutations, such as the HER2 mutation and predictive biomarkers for immunotherapy responses. In this consensus, a group of experts in the diagnosis and treatment of NSCLC selected by the Spanish Society of Pathology and the Spanish Society of Medical Oncology have evaluated currently available information and propose a series of recommendations to optimize the detection and use of biomarkers in daily clinical practice.

The prognostic role of PD-1, PD-L1, ALK, and ROS1 proteins expression in non-small cell lung carcinoma patients from Egypt

Background

Programmed death ligand-1 (PD-L1), anaplastic lymphoma kinase (ALK), and c-ros oncogene1 (ROS1) expression may influence the prognosis of non-small cell lung carcinoma (NSCLC). We aimed to investigate the prognostic and predictive significance of PD-1/PD-L1 along with c-ros ROS1 and ALK in NSCLC patients.

Methods

Immunohistochemistry used to identify ALK, ROS1, PD-1, and PD-L1 proteins expression as well as ROS1 rearrangement via fluorescence in situ hybridization, in 70 NSCLC patients. Results were related to clinicopathological feature, survival, and treatment response.

Results

Expression of ROS1, ALK, PD-1, and PD-L1 and ROS1-rearrangement were detected in 18.57%, 54.29%, 84.29%, 87.14%, and 15.71% of the cases, respectively. No association was found between ROS1, PD-1, and PD-L1 and any clinicopathological features, survival, or treatment outcome. ALK expression significantly associated with stage-IV and left-sided tumors. Epidermal growth factor receptor (EGFR) mutation and ALK-positive patients had significantly reduced progression-free survival than patients with wild type EGFR [HR: 1.99, 95% CI: 1.37–2.93, p < 0.001] and negative-ALK expression [HR: 1.46, 95% CI: 1.03–2.07, p = 0.03]. In multivariate analysis, lymph node metastasis, EGFR-mutations, and ALK were independent predictors of NSCLC. PD-L1 expression was significantly correlated with PD-1 but not with ROS1, ALK, or EGFR-mutation.

Conclusion

Positive ALK expression and EGFR-mutations are independent adverse predictors of NSCLC. Overexpression of PD-1/PD-L1 is not a significant prognostic marker in NSCLC patients receiving chemotherapy, making them susceptible to immunotherapy. Since PD-1/PD-L1 expression is independent to oncogenic driver mutations, future studies into specific immune checkpoint inhibitors combined with targeted therapies for individualized treatment of NSCLC is warranted.

Positive ALK expression and EGFR mutations are independent risk factors for NSCLC. Overexpression of PD-1/PD-L1 is not a significant prognostic factor in patients with NSCLC who are receiving chemotherapy, making them immunotherapy susceptible. Given that PD-1/PD-L1 expression is not dependent on oncogenic driver mutations, additional research into specific immune checkpoint inhibitors in combination with targeted therapies for the treatment of NSCLC on an individual basis is warranted.

Molecular diagnosis in non-small-cell lung cancer: expert opinion on ALK and ROS1 testing

The effectiveness of targeted therapies with tyrosine kinase inhibitors in non-small-cell lung cancer (NSCLC) depends on the accurate determination of the genomic status of the tumour. For this reason, molecular analyses to detect genetic rearrangements in some genes (ie, ALK, ROS1, RET and NTRK) have become standard in patients with advanced disease. Since immunohistochemistry is easier to implement and interpret, it is normally used as the screening procedure, while fluorescence in situ hybridisation (FISH) is used to confirm the rearrangement and decide on ambiguous immunostainings. Although FISH is considered the most sensitive method for the detection of ALK and ROS1 rearrangements, the interpretation of results requires detailed guidelines. In this review, we discuss the various technologies available to evaluate ALK and ROS1 genomic rearrangements using these techniques. Other techniques such as real-time PCR and next-generation sequencing have been developed recently to evaluate ALK and ROS1 gene rearrangements, but some limitations prevent their full implementation in the clinical setting. Similarly, liquid biopsies have the potential to change the treatment of patients with advanced lung cancer, but further research is required before this technology can be applied in routine clinical practice. We discuss the technical requirements of laboratories in the light of quality assurance programmes. Finally, we review the recent updates made to the guidelines for the determination of molecular biomarkers in patients with NSCLC.

ROS-1 Fusions in Non-Small-Cell Lung Cancer: Evidence to Date

The ROS-1 gene plays a major role in the oncogenesis of numerous tumors. ROS-1 rearrangement is found in 0.9–2.6% of non-small-cell lung cancers (NSCLCs), mostly lung adenocarcinomas, with a significantly higher rate of women, non-smokers, and a tendency to a younger age. It has been demonstrated that ROS-1 is a true oncogenic driver, and tyrosine kinase inhibitors (TKIs) targeting ROS-1 can block tumor growth and provide clinical benefit for the patient. Since 2016, crizotinib has been the first-line reference therapy, with two-thirds of the patients’ tumors responding and progression-free survival lasting ~20 months. More recently developed are ROS-1-targeting TKIs that are active against resistance mechanisms appearing under crizotinib and have better brain penetration. This review summarizes current knowledge on ROS-1 rearrangement in NSCLCs, including the mechanisms responsible for ROS-1 oncogenicity, epidemiology of ROS-1-positive tumors, methods for detecting rearrangement, phenotypic, histological, and molecular characteristics, and their therapeutic management. Much of this work is devoted to resistance mechanisms and the development of promising new molecules.

Fifty-five months progression-free survival with crizotinib treatment in coexistence of ALK and ROS1 rearrangements in lung adenocarcinoma: an extremely rare case and review of the literature

We wanted to present a case with coexistence of anaplastic lymphoma kinase (ALK) and c-ros oncogene 1 (ROS1) rearrangements that has been in remission for a long time with crizotinib. A 62-year-old nonsmoker male patient was diagnosed with Non-small cell lung cancer. Progression developed 9 months after the treatment, and coexistence of ALK and ROS1 positivity were detected in driver mutation analysis performed with fluorescent in situ hybridization. Crizotinib 2 × 250 mg was started in November 2016. The treatment of the patient, who has been in remission for approximately 55 months since then, continues. Until recently, the use of next-generation sequencing (NGS) was not common, but the more frequent epidermal growth factor receptor, then ALK, and finally ROS1 mutation were studied in tumor tissues. Sometimes ROS1 was not studied because there was not enough tissue left. We think that this rate will increase a little more with the widespread use of NGS from now on. Showing that ALK and ROS1 are positive together, longer survivals can be obtained by choosing therapies that are responsive to both.

Deepening the Knowledge of ROS1 Rearrangements in Non-Small Cell Lung Cancer: Diagnosis, Treatment, Resistance and Concomitant Alterations

ROS proto-oncogene 1 (ROS1) rearrangements are reported in about 1-2% of non-squamous non-small-cell lung cancer (NSCLC). After efficacy of crizotinib was demonstrated, identification of ROS1 translocations in advanced disease became fundamental to give patients the chance of specific and effective treatment. Different methods are available for detection of rearrangements, and probably the real prevalence of ROS1 rearrangements is higher than that reported in literature, as our capacity to detect gene rearrangements is improving. In particular, with next generation sequencing (NGS) techniques, we are currently able to assess multiple genes simultaneously with increasing sensitivity. This is leading to overcome the "single oncogenic driver" paradigm, and in the very near future, the co-existence of multiple drivers will probably emerge more frequently and represent a therapeutic issue. Since recently, crizotinib has been the only available therapy, but today, many other tyrosine kinase inhibitors (TKI) are emerging and seem promising both in first and subsequent lines of treatment. Indeed, novel inhibitors are also able to overcome resistance mutations to crizotinib, hypothesizing a possible sequential strategy also in ROS1-rearranged disease. In this review, we will focus on ROS1 rearrangements, dealing with diagnostic aspects, new therapeutic options, resistance issues and the coexistence of ROS1 translocations with other molecular alterations.

Focus on ROS1-Positive Non-Small Cell Lung Cancer (NSCLC): Crizotinib, Resistance Mechanisms and the Newer Generation of Targeted Therapies

Simple Summary

Genetic rearrangements of the ROS1 gene account for up to 2% of NSCLC patients who sometimes develop brain metastasis, resulting in poor prognosis. This review discusses the tyrosine kinase inhibitor crizotinib plus updates and preliminary results with the newer generation of tyrosine kinase inhibitors, which have been specifically conceived to overcome crizotinib resistance, including brigatinib, cabozantinib, ceritinib, entrectinib, lorlatinib and repotrectinib. After introducing each agent’s properties, we provide suggestions on the best approaches to identify resistance mechanisms at an early stage, and we speculate on the most appropriate second-line therapies for patients who reported disease progression following crizotinib administration.

Abstract

The treatment of patients affected by non-small cell lung cancer (NSCLC) has been revolutionised by the discovery of druggable mutations. ROS1 (c-ros oncogene) is one gene with druggable mutations in NSCLC. ROS1 is currently targeted by several specific tyrosine kinase inhibitors (TKIs), but only two of these, crizotinib and entrectinib, have received Food and Drug Administration (FDA) approval. Crizotinib is a low molecular weight, orally available TKI that inhibits ROS1, MET and ALK and is considered the gold standard first-line treatment with demonstrated significant activity for lung cancers harbouring ROS1 gene rearrangements. However, crizotinib resistance often occurs, making the treatment of ROS1-positive lung cancers more challenging. A great effort has been undertaken to identify a new generation or ROS1 inhibitors. In this review, we briefly introduce the biology and role of ROS1 in lung cancer and discuss the underlying acquired mechanisms of resistance to crizotinib and the promising new agents able to overcome resistance mechanisms and offer alternative efficient therapies.

[Application of FISH in the diagnosis of lung cancer]

Rapid advancements in the area of lung cancer therapy were determined by the discovery of molecular markers and the possibility of their therapeutic exploitation. Today's lung cancer diagnosis places high demands on pathologists. In the majority of cases, small tissue samples must suffice for diagnosis and testing of all relevant biomarkers. The minimum panel required for advanced non-small-cell lung carcinoma (NSCLC) with nonsquamous histology includes testing of EGFR, BRAF, ALK, ROS1, and PD-L1-expression. So far, only PD-L1-IHC (immunohistochemistry, IHC) is required for squamous cell carcinoma. If possible, newer biomarkers such as RET, MET, HER2, NTRK, and KRAS should be integrated in test panels. Fluorescence in situ hybridization (FISH) is a well-established molecular method for the detection of chromosomal aberrations, such as ALK-, ROS1-, and RET- translocations and amplifications, such as Her2/neu or MET. The relevance of MET-FISH for the detection of amplifications in the first-line setting is controversial, but of high importance in the recurrent setting. All equivocal or discrepant results should be validated using orthogonal methods. IHC is a suitable, thoroughly validated method for ALK and ROS1 aberration detection with the advantage of quick and cost-efficient test results and tissue conservation. All other translocations, or discrepancy between IHC and FISH, require a sequencing-based confirmation procedure. The low frequency of NTRK fusions, and high sensitivity of NTRK-IHC, suggest using IHC as a prescreening tool with subsequent sequencing-based analysis for IHC positive cases.

High prevalence of ROS1 gene rearrangement detected by FISH in EGFR and ALK negative lung adenocarcinoma

ROS1 rearrangement has become an important biomarker for targeted therapy in advanced lung adenocarcinoma (LUAD). The study aimed to evaluate the prevalence of ROS1 rearrangement in Chinese LUAD with EGFR wild-type and ALK fusion-negative status, and analyze the relationship with their clinicopathological characteristics. A large cohort of 589 patients of LUAD with EGFR/ALK wild-type, diagnosed between April 2014 and June 2018, was retrospectively analyzed. ROS1 rearrangement in all these cases was detected by FISH, and 8 selected cases with different positive and negative signals were confirmed by NGS. As a result, total of 56 cases with ROS1 rearrangements out of 589 LUADs (9.51%) were identified by FISH. The frequency of ROS1 rearrangement in women was 22.15% (35/158), which was statistically higher than 4.87% (21/431) in men (P < 0.001). The ROS1 positive rate in the patients with age < 50 years old (25.29%, 22/87) was statistically higher than that in the patients with age ≥ 50 (6.77%, 34/502) (P < 0.001). There was a trend that the frequency of ROS1 rearrangement in LUAD with stage III-IV was higher than that in stage I-II (9.56%, 39/408 vs 2.50%, 1/40), although it did not reach significant difference (P = 0.135). 37 out of 56 cases of ROS1 rearranged LUAD showed solid (n = 20, 35.71%) and invasive mucinous adenocarcinoma (n = 17, 30.36%) pathological subtypes. The median OS for patients of ROS1 rearranged LUAD treated with TKIs (n = 29) was 49.69 months (95% CI: 36.71, 62.67), compared with 32.55 months (95% CI: 23.24, 41.86) for those who did not receive TKI treatment (n = 16) (P = 0.040). The NGS results on ROS1 rearrangement in all the 8 cases were concordant with FISH results. In conclusion, high prevalence of ROS1 rearrangements occurs in EGFR/ALK wild-type LUAD detected by FISH, especially in younger, female, late stage patients, and in histological subtypes of solid and invasive mucinous adenocarcinoma.

ERK phosphorylation as a marker of RAS activity and its prognostic value in non-small cell lung cancer

BACKGROUND

Deregulated signal transduction pathways play a key role in development, progression and therapeutic resistance of non-small cell lung cancers (NSCLC). The purpose of this study is to assess the downstream markers of two well-characterized pathways and to correlate them with clinical outcome.

DESIGN

670 patients with metastatic NSCLC were prospectively enrolled in a comprehensive biomarker profiling program at a single center from 2012 to 2016. Phosphorylation of extracellular signal-regulated kinase (p-ERK), and protein kinase B (p-AKT) was assessed by standardized immunohistochemistry. Product of scores for quantity and quality of staining were calculated (immunoreactive score, 0-9). Somatic mutations of Kirsten rat sarcoma viral oncogene homolog [KRAS], epithelial growth factor receptor [EGFR], v-Raf murine sarcoma viral oncogene homolog B [BRAF] and phosphatidylinositol 3-kinase [PIK3CA]) were detected by Sanger (2012-03/2015) and amplicon NGS (04/2015-02/2016). Patients enrolled during the first year (2012) were used as discovery cohort. Patients enrolled from 2013 to 02/2016 were used as validation cohort. Clinical data were retrieved from the electronic medical records and were analyzed retrospectively.

RESULTS

Using a discovery cohort, we identified an immunoreactive score of p-ERK ≥3 to be prognostically relevant. The validation cohort confirmed that higher levels of p-ERK correlated with worse overall survival (OS) and higher proportion of RAS mutations. Multivariate analysis including established risk factors such EGFR, ALK or ROS mutations and metastatic disease showed a trend of a detrimental effect of high p-ERK on OS (HR 1.23, CI 0.94-1.59, p = 0.131 for p-ERK immunoreactive score ≥3) and time to treatment failure after first-line therapy in the validation cohort. Phosphorylated AKT did not correlate with clinical outcome.

CONCLUSION

While serving as a prognosticator in univariate analysis, highly phosphorylated ERK does not convey a significant prognostic effect for OS in the presence of other prognostic factors. Phosphorylated ERK indicates a higher activity of RAS in advanced NSCLC.

Prevalence and Clinical Impact of Concomitant Mutations in Anaplastic Lymphoma Kinase Rearrangement Advanced Non-small-Cell Lung Cancer (Guangdong Association of Thoracic Oncology Study 1055)

Background: In patients with anaplastic lymphoma kinase (ALK) rearrangement-positive advanced non–small-cell lung cancer (NSCLC), ALK inhibitors are now the standard treatment, but their clinical efficacy varies widely for each patient. In this multicenter retrospective study, we evaluated the clinical efficacy of crizotinib according to the ALK rearrangement variants and concomitant mutations present.

Patients and Methods: A total 132 patients with ALK rearrangement advanced NSCLC from 4 centers in Guangdong province, China were evaluated. All patients received crizotinib treatment and their ALK rearrangement status was identified by next-generation sequencing (NGS).

Results: The median progression-free survival (PFS) in patients with EML4-ALK rearrangement (n = 121), non-EML4-ALK rearrangement (n = 5), and EML4-ALK arrangement accompanied by non-EML4-ALK rearrangement (n = 6) was 12.8, 7.5, and 7.4 months, respectively, with no significant difference between them (p = 0.1554). Similarly, among patients with various EML4-ALK variants (variant 1, variant 3a/b, and other variants), the median PFS values were again comparable. According to baseline NGS data, the median PFS in patients who had ALK rearrangement only, ALK rearrangement and concomitant tumor-suppressor gene mutations, and ALK rearrangement and concomitant oncogene mutations was 14.2, 10.9, and 4.9 months, respectively; (p = 0.0002). A multivariable analysis indicated that concomitant oncogene mutations and tumor-suppressor gene mutations were both negative factors influencing the efficacy of crizotinib in ALK rearrangement NSCLC.

Conclusion: Concomitant oncogene mutations and tumor-suppressor gene mutations had negative effects on the efficacy of crizotinib, while various ALK variants had a similar influence.

ROS1-dependent cancers - biology, diagnostics and therapeutics

The proto-oncogene ROS1 encodes a receptor tyrosine kinase with an unknown physiological role in humans. Somatic chromosomal fusions involving ROS1 produce chimeric oncoproteins that drive a diverse range of cancers in adult and paediatric patients. ROS1-directed tyrosine kinase inhibitors (TKIs) are therapeutically active against these cancers, although only early-generation multikinase inhibitors have been granted regulatory approval, specifically for the treatment of ROS1 fusion-positive non-small-cell lung cancers; histology-agnostic approvals have yet to be granted. Intrinsic or extrinsic mechanisms of resistance to ROS1 TKIs can emerge in patients. Potential factors that influence resistance acquisition include the subcellular localization of the particular ROS1 oncoprotein and the TKI properties such as the preferential kinase conformation engaged and the spectrum of targets beyond ROS1. Importantly, the polyclonal nature of resistance remains underexplored. Higher-affinity next-generation ROS1 TKIs developed to have improved intracranial activity and to mitigate ROS1-intrinsic resistance mechanisms have demonstrated clinical efficacy in these regards, thus highlighting the utility of sequential ROS1 TKI therapy. Selective ROS1 inhibitors have yet to be developed, and thus the specific adverse effects of ROS1 inhibition cannot be deconvoluted from the toxicity profiles of the available multikinase inhibitors. Herein, we discuss the non-malignant and malignant biology of ROS1, the diagnostic challenges that ROS1 fusions present and the strategies to target ROS1 fusion proteins in both treatment-naive and acquired-resistance settings.

A comprehensive study on the oncogenic mutation and molecular pathology in Chinese lung adenocarcinoma patients

BACKGROUND

Several genetic driver alterations have been identified in micropapillary lung adenocarcinoma (MPA). However, the frequency of co-alteration of ROS1, EGFR, and EML4-ALK is yet unclear. Herein, we investigated the relationship between clinicopathologic characteristics and well-identified driver mutations of MPA compared with non-micropapillary lung adenocarcinoma (LA).

METHODS

Formalin-fixed paraffin-embedded (FFPE) sections derived from lung adenocarcinoma patients who never received adjuvant chemotherapy or radiation therapy prior to surgical resection were collected from October 2016 to June 2019. EGFR mutations, ROS1 rearrangements, and EML4-ALK fusion were identified in a set of 131 MPA and LA cases by using the amplification refractory mutation system (ARMS). The response rate and duration of response were assessed using Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1).

RESULTS

EGFR mutations had occurred in 42 (76.4%) MPA patients and 42 (55.3%) LA patients. Interestingly, ROS1 rearrangements were highly enriched only in the MPA cases (6/55, 10.9%) but rarely in the LA cases (1/76, 1.3%). Furthermore, 7.3% (4/55) MPA samples had double gene mutations, while only 1.3% (1/76) LA cases had double gene alterations. Of 5 patients with harboring two driver oncogene mutations, four patients (80%) obtained partial response, and one patient (20%) suffered recurrence.

CONCLUSIONS

A higher prevalence of ROS1 rearrangement or combined mutations of ROS1, EGFR, and EML4-ALK may play a critical role in the tumorigenesis of MPA. These findings provide a novel therapeutic strategy for patients with malignant MPA through combining TKIs than one TKI.

Incidence of ROS1-Rearranged Non-Small-Cell Lung Carcinoma in India and Efficacy of Crizotinib in Lung Adenocarcinoma Patients

BACKGROUND

The ROS1 gene is a member of the "sevenless" subfamily of tyrosine-kinase insulin-receptor genes. ROS1-fusion rearrangement causes constitutive downstream signal transduction, with an oncogenic role in non-small-cell lung carcinoma (NSCLC). Fortunately, crizotinib, an ALK1 tyrosine-kinase inhibitor, provides long-term disease control. The objective of this molecular epidemiological study was to estimate the frequency of ROS1 rearrangements and evaluate treatment outcomes with crizotinib therapy.

METHODS

Patients with stage IV NSCLC adenocarcinoma histology were considered for this study. The study was conducted according to the ethical principles stated in the latest version of the Declaration of Helsinki and the applicable guidelines for good clinical practice. Clinical characteristics and treatment details were collected from patients' medical records.

RESULTS

A total of 709 stage IV NSCLC adenocarcinoma patients were included in the study. There were 457 (64.46%) men and 252 (35.54%) women, with a median age of 60 years. ROS1-gene rearrangement was positive in 20 (2.82%) cases, 13 using Fluorescent In-Situ Hybridization (FISH), and two and five cases, respectively, using immunohistochemistry (IHC) and next-generation sequencing (NGS), followed by confirmation with FISH. Fourteen of the 20 patients with ROS1-gene rearrangement received crizotinib therapy, with an objective response rate of 64.28%. At a median follow-up of 6 months, the study had not achieved the end points of median progression free survival and overall survival.

CONCLUSION

ROS1-gene rearrangement was present at a relatively higher frequency of 2.8% in north Indian patients with lung adenocarcinoma and was successfully targeted by crizotinib therapy. Although the only US Food and Drug Administration and Conformité Européenne approved method for testing ROS1 rearrangement is NGS, FISH alone or IHC with D4D6 antibody as initial screen with subsequent confirmation of IHC-positive cases by FISH are cost-effective methods in institutions lacking NGS facilities.

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.

Assessment of a New ROS1 Immunohistochemistry Clone (SP384) for the Identification of ROS1 Rearrangements in Patients with Non-Small Cell Lung Carcinoma: the ROSING Study

INTRODUCTION

The ROS1 gene rearrangement has become an important biomarker in NSCLC. The College of American Pathologists/International Association for the Study of Lung Cancer/Association for Molecular Pathology testing guidelines support the use of ROS1 immunohistochemistry (IHC) as a screening test, followed by confirmation with fluorescence in situ hybridization (FISH) or a molecular test in all positive results. We have evaluated a novel anti-ROS1 IHC antibody (SP384) in a large multicenter series to obtain real-world data.

METHODS

A total of 43 ROS1 FISH-positive and 193 ROS1 FISH-negative NSCLC samples were studied. All specimens were screened by using two antibodies (clone D4D6 from Cell Signaling Technology and clone SP384 from Ventana Medical Systems), and the different interpretation criteria were compared with break-apart FISH (Vysis). FISH-positive samples were also analyzed with next-generation sequencing (Oncomine Dx Target Test Panel, Thermo Fisher Scientific).

RESULTS

An H-score of 150 or higher or the presence of at least 70% of tumor cells with an intensity of staining of 2+ or higher by the SP384 clone was the optimal cutoff value (both with 93% sensitivity and 100% specificity). The D4D6 clone showed similar results, with an H-score of at least 100 (91% sensitivity and 100% specificity). ROS1 expression in normal lung was more frequent with use of the SP384 clone (p < 0.0001). The ezrin gene (EZR)-ROS1 variant was associated with membranous staining and an isolated green signal FISH pattern (p = 0.001 and p = 0.017, respectively).

CONCLUSIONS

The new SP384 ROS1 IHC clone showed excellent sensitivity without compromising specificity, so it is another excellent analytical option for the proposed testing algorithm.

Intrinsic resistance to EGFR-Tyrosine Kinase Inhibitors in EGFR-Mutant Non-Small Cell Lung Cancer: Differences and Similarities with Acquired Resistance

Activating mutations in the epidermal growth factor receptor gene occur as early cancer-driving clonal events in a subset of patients with non-small cell lung cancer (NSCLC) and result in increased sensitivity to EGFR-tyrosine-kinase-inhibitors (EGFR-TKIs). Despite very frequent and often prolonged clinical response to EGFR-TKIs, virtually all advanced EGFR-mutated (EGFRM+) NSCLCs inevitably acquire resistance mechanisms and progress at some point during treatment. Additionally, 20-30% of patients do not respond or respond for a very short time (<3 months) because of intrinsic resistance. While several mechanisms of acquired EGFR-TKI-resistance have been determined by analyzing tumor specimens obtained at disease progression, the factors causing intrinsic TKI-resistance are less understood. However, recent comprehensive molecular-pathological profiling of advanced EGFRM+ NSCLC at baseline has illustrated the co-existence of multiple genetic, phenotypic, and functional mechanisms that may contribute to tumor progression and cause intrinsic TKI-resistance. Several of these mechanisms have been further corroborated by preclinical experiments. Intrinsic resistance can be caused by mechanisms inherent in EGFR or by EGFR-independent processes, including genetic, phenotypic or functional tumor changes. This comprehensive review describes the identified mechanisms connected with intrinsic EGFR-TKI-resistance and differences and similarities with acquired resistance and among clinically implemented EGFR-TKIs of different generations. Additionally, the review highlights the need for extensive pre-treatment molecular profiling of advanced NSCLC for identifying inherently TKI-resistant cases and designing potential combinatorial targeted strategies to treat them.

Clinical features and therapeutic options in non-small cell lung cancer patients with concomitant mutations of EGFR, ALK, ROS1, KRAS or BRAF

Background

Although oncogenic driver mutations were thought to be mutually exclusive in non‐small cell lung cancer (NSCLC), certain tumors harbor co‐occurring mutations and represent a rare molecular subtype. The evaluation of the clinical features and therapeutic response associated with this NSCLC subtype will be vital for understanding the heterogeneity of treatment response and improving the management of these patients.

Methods

This retrospective study included 3774 samples from patients diagnosed with NSCLC. All samples were screened for EGFR, ALK, ROS1, KRAS, and BRAF mutation using the amplification‐refractory mutation system. The relationship between concomitant driver mutations and clinicopathologic characteristics, and patient clinical outcomes were evaluated.

Results

Sixty‐three (1.7%) samples had more than one driver gene mutation. Among these, 43 were coalterations with an EGFR mutation, 20 with an ALK rearrangement, and eight with an ROS1 rearrangement. Except for ROS1 concomitant mutations that were more frequent in male patients (87.5%, P = 0.020), the clinicopathological features of the concomitant mutation patients were not significantly different from those harboring a single EGFR, ALK, or ROS1 mutation. Furthermore, first‐line EGFR‐TKI treatment did not significantly improve the progression‐free survival (PFS) of patients harboring EGFR concomitant mutation, compared to patients harboring a single EGFR mutation. However, for EGFR concomitant mutation patients, TKI therapy was more effective than chemotherapy (median PFS of 10.8 vs 5.2 months, P = 0.023). Lastly, KRAS mutations did not influence the EGFR‐TKI therapy treatment effect.

Conclusion

In this study, concomitant mutations were found in 1.7% of the NSCLC. EGFR‐TKI therapy was more effective than chemotherapy for patients harboring EGFR concomitant mutation, and ROS1 concomitant mutations were more frequent in male patients. For patients harboring coalterations with an ALK or ROS1 rearrangement, we should be cautious when considering the therapeutic options.

PD-L1 expression in ROS1-rearranged non-small cell lung cancer: A study using simultaneous genotypic screening of EGFR, ALK, and ROS1

Background

The aim of the current study was to investigate the prevalence and clinicopathologic characteristics of ROS1‐rearranged non‐small cell lung cancer (NSCLC) in routine genotypic screening in conjunction with the study of PD‐L1 expression, a biomarker for first‐line treatment decisions.

Methods

Reflex simultaneous genotypic screening for EGFR by peptide nucleic acid clamping, and ALK and ROS1 by fluorescence in situ hybridization (FISH) was performed on consecutive NSCLC cases at the time of initial pathologic diagnosis. We evaluated genetic aberrations, clinicopathologic characteristics, and PD‐L1 tumor proportion score (TPS) using a PD‐L1 22C3 assay kit.

Results

In 407 consecutive NSCLC patients, simultaneous genotyping identified 14 (3.4%) ROS1 and 19 (4.7%) ALK rearrangements, as well as 106 (26%) EGFR mutations. These mutations were mutually exclusive and were found in patients with similar clinical features, including younger age, a prevalence in women, adenocarcinoma, and advanced stage. The PD‐L1 assay was performed on 130 consecutive NSCLC samples. High PD‐L1 expression (TPS ≥ 50%) was observed in 29 (22.3%) tumors. PD‐L1 expression (TPS ≥ 1%) was significantly associated with wild type EGFR, while ROS1 rearrangement was associated with high PD‐L1 expression. Of the 14 cases with ROS1 rearrangement, 12 (85.7%) showed PD‐L1 expression and 5 (35.7%) showed high PD‐L1 expression.

Conclusion

In the largest consecutive routine Asian NSCLC cohort analyzed to date, we found that high PD‐L1 expression frequently overlapped with ROS1 rearrangement, while it negatively correlated with EGFR mutations.

A novel co-existing ZCCHC8-ROS1 and de-novo MET amplification dual driver in advanced lung adenocarcinoma with a good response to crizotinib

In non-small cell lung cancer (NSCLC), driver gene alterations, such as EGFR, ALK, MET, and ROS1, are usually mutually exclusive. Few clinical cases with co-existing ROS1 fusion and de-novo MET amplification have been reported. In addition, the efficacy of crizotinib in Chinese patients with driver co-existing alterations is uncertain. A 65-year-old female was diagnosed with lung adenocarcinoma metastatic to the brain. She had sufficient tumor tissue for detection of the target gene; however, common driver gene mutations, such as EGFR-wild and ALK-negative, were not initially detected. The patient was ultimately shown to have both ZCCHC8-ROS1 and de-novo MET gene amplification through next-generation sequencing with sensitivity to the targeted therapy of crizotinib. Unfortunately, the progression-free survival was only 6 months in length. We report here the first patient with co-existing ROS1 fusion and de-novo MET amplification to receive crizotinib in China. Treatment of our patient was effective with targeted therapy based on a precise diagnosis. Advanced or metastatic NSCLC patients with co-existing ROS1 fusion and de-novo MET amplification are sensitive to crizotinib. These uncommon driver gene mutations may be missed using the current first-generation detection assay. We must be aware of the incidence of concomitant ROS1 fusion and de-novo MET amplification because NSCLC patients could benefit from targeted therapy.

Fatal interstitial lung disease associated with Crizotinib pathologically confirmed by percutaneous lung biopsy in a patient with ROS1-rearranged advanced non-small-cell lung cancer: a case report

Background

Crizotinib is a multi-target inhibitor approved for the treatment of advanced non-small-cell lung cancer patients with a ROS1 rearrangement. However, interstitial lung disease is a rare but severe and fatal side effect of crizotinib that should lead to immediate discontinuation of the drug. Unfortunately, the pathophysiology, molecular mechanism and risk factors for crizotinib-induced interstitial lung disease remain poorly understood.

Case presentation

We first identified and reported interstitial lung disease induced de novo by crizotinib in a 47-year-old female patient who was diagnosed with advanced lung adenocarcinoma with a ROS1 rearrangement in a malignant pleural effusion. Subsequent next-generation sequencing analysis revealed both ROS1 rearrangement and an EGFR exon 19 deletion mutation in lung biopsy specimens, which were histologically confirmed to be interstitial lung disease. Although crizotinib treatment was ceased immediately and a shock treatment with high-dose methylprednisolone as well as other necessary treatment procedures was applied to reverse the interstitial lung disease process, the patient died.

Conclusions

The present case indicates that while treating non-small-cell lung cancer patients with crizotinib, it is important to constantly monitor any newly emerging respiratory symptoms and unexplained imaging changes, which may suggest an adverse effect related to drug-induced interstitial lung disease or even lethality. Histopathology and molecular pathological examination of lung biopsy specimens may help clinicians understand the development mechanism and exclude other causes.

Molecular dissection of effector mechanisms of RAS-mediated resistance to anti-EGFR antibody therapy

Monoclonal antibodies targeting the epidermal growth factor receptor (EGFR), cetuximab and panitumumab, are a mainstay of metastatic colorectal cancer (mCRC) treatment. However, a significant number of patients suffer from primary or acquired resistance. RAS mutations are negative predictors of clinical efficacy of anti-EGFR antibodies in patients with mCRC. Oncogenic RAS activates the MAPK and PI3K/AKT pathways, which are considered the main effectors of resistance. However, the relative impact of these pathways in RAS-mutant CRC is less defined. A better mechanistic understanding of RAS-mediated resistance may guide development of rational intervention strategies. To this end we developed cancer models for functional dissection of resistance to anti-EGFR therapy in vitro and in vivo. To selectively activate MAPK- or AKT-signaling we expressed conditionally activatable RAF-1 and AKT in cancer cells. We found that either pathway independently protected sensitive cancer models against anti-EGFR antibody treatment in vitro and in vivo. RAF-1- and AKT-mediated resistance was associated with increased expression of anti-apoptotic BCL-2 proteins. Biomarkers of MAPK and PI3K/AKT pathway activation correlated with inferior outcome in a cohort of mCRC patients receiving cetuximab-based therapy. Dual pharmacologic inhibition of PI3K and MEK successfully sensitized primary resistant CRC models to anti-EGFR therapy. In conclusion, combined targeting of MAPK and PI3K/AKT signaling, but not single pathways, may be required to enhance the efficacy of anti-EGFR antibody therapy in patients with RAS-mutated CRC as well as in RAS wild type tumors with clinical resistance.

MET Expression in Advanced Non-Small-Cell Lung Cancer: Effect on Clinical Outcomes of Chemotherapy, Targeted Therapy, and Immunotherapy

BACKGROUND

The receptor tyrosine kinase MET is implicated in malignant transformation, tumor progression, metastasis, and acquired treatment resistance. We conducted an analysis of the effect of MET expression and MET genomic aberrations on the outcome of patients with advanced or metastatic pulmonary adenocarcinomas prospectively enrolled in an institutional precision oncology program.

PATIENTS AND METHODS

Standardized immunohistochemistry (IHC) analyses of MET and markers of pathway activation were available in 384 patients, and next-generation sequencing-based MET hotspot mutation analyses were available from 892 patients. Clinical data were retrieved with a median follow-up from initial diagnosis of 37 months.

RESULTS

High MET expression, defined as MET IHC 3+ or MET H-Score in the upper quartile, was observed in 102 of 384 patients (26.6%). MET exon 14 mutations were only detected in 7 of 892 patients (0.78%). High MET expression correlated with activation markers of the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathways only in cases without Kirsten rat sarcoma viral oncogene homolog (KRAS), epidermal growth factor receptor (EGFR), v-Raf murine sarcoma viral oncogene homolog B (BRAF), anaplastic lymphoma kinase (ALK) and proto-oncogene tyrosine-protein kinase ROS (ROS1) aberrations. There was no association of MET expression with outcome during chemotherapy. High MET expression negatively affected the outcome during EGFR-targeting therapy but was associated with more favorable results with programmed death 1/programmed death ligand 1 (PD-L1)-directed therapy, independent of smoking history, PD-L1 expression or KRAS mutation. Two patients with MET exon 14 mutation and high PD-L1 expression failed to respond to pembrolizumab.

CONCLUSION

MET expression affects the outcomes of targeted therapies in non-small-cell lung cancer, thus supporting the development of biomarker-informed combination strategies. The interaction of MET expression and MET mutation with immune checkpoint inhibitor therapy is novel and merits further investigation.

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.

The rationale for druggability of CCDC6-tyrosine kinase fusions in lung cancer

Gene fusions occur in up to 17% of solid tumours. Oncogenic kinases are often involved in such fusions. In lung cancer, almost 30% of patients carrying an activated oncogene show the fusion of a tyrosine kinase to an heterologous gene. Several genes are partner in the fusion with the three kinases ALK, ROS1 and RET in lung. The impaired function of the partner gene, in combination with the activation of the kinase, may alter the cell signaling and promote the cancer cell addiction to the oncogene. Moreover, the gene that is partner in the fusion to the kinase may affect the response to therapeutics and/or promote resistance in the cancer cells. Few genes are recurrent partners in tyrosine kinase fusions in lung cancer, including CCDC6, a recurrent partner in ROS1 and RET fusions, that can be selected as possible target for new strategies of combined therapy including TKi.

Dual drive coexistence of EML4-ALK and TPM3-ROS1 fusion in advanced lung adenocarcinoma

We report a case of concomitant EML4-ALK and TPM3-ROS1 fusion in non-small cell lung cancer (NSCLC) in a 47-year-old Chinese man and review the clinical characteristics of this type double of fusion. The patient presented with a local tumor of the left upper lobe and underwent thoracoscopy. Postoperative surgical pathologic staging revealed T1a N0 M0 stage IA. Histological examination of the tumor showed lung adenocarcinoma. Ventana ALK (D5F3) assay of the left lung tissue was ALK negative; however, immunohistochemical assay was positive for ROS1 protein. Using next generation sequencing, we found that the tumor had concomitant EML4-ALK and TPM3-ROS1 fusion. No recurrence was observed during seven months of follow-up. Precise diagnostic techniques allow the detection of concomitant ROS1 fusion and other driver genes, including ALK or EGFR; therefore oncologists should consider this rare double mutation in NSCLC patients. Further exploration of treatment models is required to provide additional therapeutic options.

Recent Advances in Targeting ROS1 in Lung Cancer

ROS1 is a validated therapeutic target in NSCLC. In a phase I study, the multitargeted MET proto-oncogene, receptor tyrosine kinase/anaplastic lymphoma kinase/ROS1 inhibitor crizotinib demonstrated remarkable efficacy in ROS1-rearranged NSCLCs and consequently gained approval by the United States Food and Drug Administration and by the European Medicines Agency in 2016. However, similar to other oncogene-driven lung cancers, ROS1-rearranged lung cancers treated with crizotinib eventually acquire resistance, leading to disease relapse. Novel ROS1 inhibitors and therapeutic strategies are therefore needed. Insights into the mechanisms of resistance to ROS1-directed tyrosine kinase inhibitors are now beginning to emerge and are helping to guide the development of new ROS1 inhibitors. This review discusses the biology and diagnosis of ROS1-rearranged NSCLC, and current and emerging treatment options for this disease. Future challenges in the field are highlighted.

ROS1 [corrected]

ROS1 is a receptor tyrosine kinase that has recently been shown to undergo gene rearrangements in~1%-2% of non-small cell lung carcinoma (NSCLC) and in a variety of other tumours including cholangiocarcinoma, gastric carcinoma, colorectal carcinoma and in spitzoid neoplasms, glioblastoma and inflammatory myofibroblastic tumours. The ROS1 gene fusion undergoes constitutive activation, regulates cellular proliferation and is implicated in carcinogenesis. ROS1 fusions can be detected by fluorescence in situ hybridisation, real-time PCR, sequencing-based techniques and immunohistochemistry-based methods in clinical laboratories. The small molecule tyrosine kinase inhibitor, crizotinib has been shown to be an effective inhibitor of ROS1 and has received Food and Drug Administration approval for treatment of advanced NSCLC. The current review is an update on the clinical findings and detection methods of ROS1 in clinical laboratories in NSCLC and other tumours.

Detection of ROS1 rearrangement in non-small cell lung cancer: current and future perspectives

ROS1 rearrangement characterizes a small subset (1%-2%) of non-small cell lung cancer and is associated with slight/never smoking patients and adenocarcinoma histology. Identification of ROS1 rearrangement is mandatory to permit targeted therapy with specific inhibitors, demonstrating a significantly better survival when compared with conventional chemotherapy. Detection of ROS1 rearrangement is based on in situ (immunohistochemistry, fluorescence in situ hybridization) and extractive non-in situ assays. While fluorescence in situ hybridization still represents the gold standard in clinical trials, this technique may fail to recognize rearrangements of ROS1 with some gene fusion partner. On the other hand, immunohistochemistry is the most cost-effective screening technique, but it seems to be characterized by low specificity. Extractive molecular assays are expensive and laborious methods, but they specifically recognize almost all ROS1 fusions using a limited amount of mRNA even from formalin-fixed, paraffin-embedded tumor tissues. This review is a discussion on the present and futuristic diagnostic scenario of ROS1 identification in lung cancer.

Immunohistochemistry of Pulmonary Biomarkers: A Perspective From Members of the Pulmonary Pathology Society

The use of immunohistochemistry for the determination of pulmonary carcinoma biomarkers is a well-established and powerful technique. Immunohistochemisty is readily available in pathology laboratories, is relatively easy to perform and assess, can provide clinically meaningful results very quickly, and is relatively inexpensive. Pulmonary predictive biomarkers provide results essential for timely and accurate therapeutic decision making; for patients with metastatic non-small cell lung cancer, predictive immunohistochemistry includes ALK and programmed death ligand-1 (PD-L1) (ROS1, EGFR in Europe) testing. Handling along proper methodologic lines is needed to ensure patients receive the most accurate and representative test outcomes.

Nonsmall cell lung carcinoma: diagnostic difficulties in small biopsies and cytological specimens

The pathological and molecular classification of lung cancer has become substantially more complex over the past decade. For diagnostic purposes on small samples, additional stains are frequently required to distinguish between squamous cell carcinoma and adenocarcinoma. Subsequently, for advanced nonsquamous cell nonsmall cell lung carcinoma (NSCLC) patients, predictive analyses on epidermal growth factor receptor, anaplastic lymphoma kinase and ROS1 are required. In NSCLCs negative for these biomarkers, programmed death ligand-1 immunohistochemistry is performed. Small samples (biopsy and cytology) require “tissue” management, which is best achieved by the interaction of all physicians involved.

Atrial fibrillation was changed into sinus bradycardia in a ROS1-positive advanced lung adenocarcinoma patient who achieved durable response to Crizotinib: A case report and literature review

RATIONAL

The c-ros oncogene 1 receptor tyrosine kinase (ROS1)-rearrangements represent a new and rare genetic subtype of non-small-cell lung cancer. In recent years, the use of crizotinib in ROS1-rearranged lung cancer exhibits significant clinical efficacy. Crizotinib is generally well tolerated and the most frequent adverse events include visual disorders, gastrointestinal disturbances, cardiac, and endocrine abnormalities. From a cardiac perspective, crizotinib is associated with 2 main cardiac effects, QT interval prolongation and bradycardia.

PATIENT CONCERNS AND DIAGNOSES

We reported a case of a 67-year-old man with ROS1-rearranged advanced lung adenocarcinoma.

INTERVENTIONS

Crizotinib was initiated as first-line treatment, combined with whole brain radiation therapy.

OUTCOMES

Interestingly, after treatment of crizotinib, the patient suffered a transient QTc interval prolongation and his persistent atrial fibrillation was changed into sinus bradycardia. Only 22 days after crizotinib treatment, the patient's tumor achieved a partial response. So far the patient has taken crizotinib for >19 months with no evidence of disease progression.

LESSONS

The present study demonstrates dramatic benefit of crizotinib for patients with ROS1 rearrangement. Besides, we should caution the cardiac effects caused by crizotinb and our case provides evidence that crizotinib may be safe for patients with atrial fibrillation under close monitoring.

ROS1 Fusions Rarely Overlap with Other Oncogenic Drivers in Non-Small Cell Lung Cancer

INTRODUCTION

Chromosomal rearrangements involving the gene ROS1 define a distinct molecular subset of NSCLCs with sensitivity to ROS1 inhibitors. Recent reports have suggested a significant overlap between ROS1 fusions and other oncogenic driver alterations, including mutations in EGFR and KRAS.

METHODS

We identified patients at our institution with ROS1-rearranged NSCLC who had undergone testing for genetic alterations in additional oncogenes, including EGFR, KRAS, and anaplastic lymphoma receptor tyrosine kinase gene (ALK). Clinicopathologic features and genetic testing results were reviewed. We also examined a separate database of ROS1-rearranged NSCLCs identified through the commercial FoundationOne assay (Foundation Medicine, Cambridge, MA).

RESULTS

Among 62 patients with ROS1-rearranged NSCLC evaluated at our institution, none harbored concurrent ALK fusions (0%) or EGFR activating mutations (0%). KRAS mutations were detected in two cases (3.2%), one of which harbored a concurrent noncanonical KRAS I24N mutation of unknown biological significance. In a separate ROS1 fluorescence in situ hybridization-positive case, targeted sequencing failed to confirm a ROS1 fusion but instead identified a KRAS G13D mutation. No concurrent mutations in B-Raf proto-oncogene, serine/threonine kinase gene (BRAF), erb-b2 receptor tyrosine kinase 2 gene (ERBB2), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha gene (PIK3CA), AKT/serine threonine kinase 1 gene (AKT1), or mitogen-activated protein kinase kinase 1 gene (MAP2K1) were detected. Analysis of an independent data set of 166 ROS1-rearranged NSCLCs identified by FoundationOne demonstrated rare cases with co-occurring driver mutations in EGFR (one of 166) and KRAS (three of 166) and no cases with co-occurring ROS1 and ALK rearrangements.

CONCLUSIONS

ROS1 rearrangements rarely overlap with alterations in EGFR, KRAS, ALK, or other targetable oncogenes in NSCLC.