Individualized targeted treatment in a case of a rare TFG::ROS1 fusion positive inflammatory myofibroblastic tumor (IMT)

BACKGROUND

Inflammatory myofibroblastic tumor (IMTs) are rare mesenchymal neoplasms with slow growth. Resection is considered as therapeutic standard, with chemotherapy being insufficiently effective in advanced disease. ALK translocations are present in 50% of cases, ROS1 fusions (YWHAE::ROS1, TFG::ROS1) are extremely rare. Here, we present a case with TFG::ROS1 fusion and highlight the significance of molecular tumor boards (MTBs) in clinical precision oncology for post-last-line therapy.

CASE PRESENTATION

A 32-year-old woman presented with IMT diagnosed at age 27 for biopsy and treatment evaluation. Previous treatments included multiple resections and systemic therapy with vinblastine, cyclophosphamide, and methotrexate. A computed tomography scan showed extensive tumor infiltration of the psoas muscles and the posterior abdomen. Next generation sequencing revealed an actionable ROS1 fusion (TFG::ROS1) with breakpoints at exon 4/35 including the kinase domain and activating the RAS-pathway. TFG, the Trk-fused gene, exerts functions such as intracellular trafficking and exhibits high sequence homology between species. Based on single reports about efficacy of ROS1-targeting in ROS1 translocation positive IMTs the patient was started on crizotinib, an ATP-competitive small molecule c-MET, ALK and ROS1-inhibitor. With a follow-up of more than 9 months, the patient continues to show a profound response with major tumor regression, improved quality of life and no evidence for severe adverse events.

CONCLUSION

This case underscores the importance of the availability of modern molecular diagnostics and interdisciplinarity in precision oncology to identify rare, disease-defining genotypes that make an otherwise difficult-to-treat disease targetable.

The Additional Exclusions of ROS1 Fusions (In Addition to EGFR Mutation and ALK Fusions) in the Cemiplimab NSCLC FDA Indication (EMPOWER-Lung 1 and -Lung 3). Catching Up with Current Scientific View of Immunotherapy in Never-Smoker Predominant Actionable Driver Mutation Positive NSCLC?

Cemiplimab is one of seven immune checkpoint inhibitors (ICIs) approved for the first-line (1L) treatment of advanced NSCLC in the US based on EMPOWER-Lung 1 and -Lung 3 trials. In addition to exclusion of NSCLC patients harboring EGFR mutations and ALK fusion from 1L treatment with ICIs, exclusion of ROS1 fusion is an additional unique exclusion the use of criterion for cemiplimab in the US FDA indication based on the design of the EMPOWER lung trials. We review the effectiveness of ICIs in never-smoker predominant NSCLC with driver mutations (EGFR, ALK, ROS1, RET, HER2) and question whether exclusion of ROS1 fusion would put cemiplimab at a competitive disadvantage given the requirement for insurance to prove ROS1 fusion negativity. We further discuss whether the US FDA as a regulatory authority has the right and responsibility to harmonize the use of ICIs in these actionable driver mutations to standardize community practice for the benefit of patients and to advance the development of next-generation treatment for these driver mutations.

ADK-VR2, a cell line derived from a treatment-naïve patient with SDC4-ROS1 fusion-positive primarily crizotinib-resistant NSCLC: a novel preclinical model for new drug development of ROS1-rearranged NSCLC

BACKGROUND

ROS1 fusions are driver molecular alterations in 1-2% of non-small cell lung cancers (NSCLCs). Several tyrosine kinase inhibitors (TKIs) have shown high efficacy in patients whose tumors harbour a ROS1 fusion. However, the limited availability of preclinical models of ROS1-positive NSCLC hinders the discovery of new drugs and the understanding of the mechanisms underlying drug resistance and strategies to overcome it.

METHODS

The ADK-VR2 cell line was derived from the pleural effusion of a treatment-naïve NSCLC patient bearing SDC4-ROS1 gene fusion. The sensitivity of ADK-VR2 and its crizotinib-resistant clone ADK-VR2 AG143 (selected in 3D culture in the presence of crizotinib) to different TKIs was tested in vitro, in both 2D and 3D conditions. Tumorigenic and metastatic ability was assessed in highly immunodeficient mice. In addition, crizotinib efficacy on ADK-VR2 was evaluated in vivo.

RESULTS

2D-growth of ADK-VR2 cells was partially inhibited by crizotinib. On the contrary, the treatment with other TKIs, such as lorlatinib, entrectinib and DS-6051b, did not result in cell growth inhibition. TKIs showed dramatically different efficacy on ADK-VR2 cells, depending on the cell culture conditions. In 3D culture, ADK-VR2 growth was indeed almost totally inhibited by lorlatinib and DS-6051b. The clone ADK-VR2 AG143 showed higher resistance to crizotinib treatment in vitro, compared to its parental cell line, in both 2D and 3D cultures. Similarly to ADK-VR2, ADK-VR2 AG143 growth was strongly inhibited by lorlatinib in 3D conditions. Nevertheless, ADK-VR2 AG143 sphere formation was less affected by TKIs treatment, compared to the parental cell line. In vivo experiments highlighted the high tumorigenic and metastatic ability of ADK-VR2 cell line, which, once injected in immunodeficient mice, gave rise to both spontaneous and experimental lung metastases while the crizotinib-resistant clone ADK-VR2 AG143 showed a slower growth in vivo. In addition, ADK-VR2 tumor growth was significantly reduced but not eradicated by crizotinib treatment.

CONCLUSIONS

The ADK-VR2 cell line is a promising NSCLC preclinical model for the study of novel targeted therapies against ROS1 fusions and the mechanisms of resistance to TKI therapies.

Case Report: Adjuvant Crizotinib Therapy Exerted Favorable Survival Benefit in a Resectable Stage IIIA NSCLC Patient With Novel LDLR-ROS1 Fusion

Novel adjuvant strategies are needed to optimize outcomes after complete surgical resection in patients with early-stage non-small-cell lung cancer (NSCLC). The adjuvant treatment of ROS Proto-Oncogene 1 (ROS1) fusion-positive resected NSCLC is challenging because there is no curative confirmed randomized controlled trial. Next-generation sequencing (NGS) and immunohistochemistry (IHC) staining were performed on the biopsy sample. In this case, we identified a novel LDLR–ROS1 fusion in a resectable stage IIIA NSCLC patient. The patient received crizotinib as adjuvant treatment and achieved recurrence-free survival (RFS) for 29 months, without significant symptoms of toxicity. In this case, we report a novel LDLR–ROS1 fusion responding to crizotinib in a patient with lung adenocarcinoma, supporting the use of adjuvant treatment with the ROS1 inhibitor exerting clinical survival benefit in ROS1 fusion-positive resected NSCLC.

BRAF V600E Mediates Crizotinib Resistance and Responds to Dabrafenib and Trametinib in a ROS1-Rearranged Non-Small Cell Lung Cancer: A Case Report

Crizotinib, a multitargeted MET/ALK/ROS1 tyrosine kinase inhibitor, has been approved for the treatment of ROS1 fusion–positive non‐small cell lung cancers (NSCLCs). However, “on‐target” or “off‐target” resistance alterations often emerge that confer the drug resistance. Patients with ROS1‐rearranged NSCLC who develop crizotinib resistance, especially those acquiring “off‐target” resistance mutations, still lack effective therapeutic options for after crizotinib treatment. Herein, we reported a patient with stage IVb lung adenocarcinoma harboring ROS1 fusion, who acquired a BRAF V600E and lost the ROS1 fusion after progression on crizotinib. It was deduced that the V600E may originate from a subclone with an extremely low fraction that was independent of ROS1 fusion–positive cells. The patient was subsequently treated with dabrafenib and trametinib combination and achieved a partial response lasting for more than 6 months. Our study revealed that BRAF V600E can confer the crizotinib resistance in ROS1 fusion–positive NSCLC and presented the first case showing that the treatment with dabrafenib and trametinib can serve as an effective option for later‐line treatment for this molecular‐defined subgroup.

Rearrangements of the ROS1 gene occur in 1%–2% of non‐small cell lung cancers, characterizing a distinct molecular subgroup. This article reports a case of stage IVb lung cancer in a patient with ROS1 fusion who acquired a BRAF V600E fusion after progression on crizotinib.

Response to Immune Checkpoint Inhibition as Monotherapy or in Combination With Chemotherapy in Metastatic ROS1-Rearranged Lung Cancers

INTRODUCTION

ROS1 fusions are oncogenic drivers in 1% to 3% of NSCLCs. The activity of immune checkpoint inhibitor (ICI) monotherapy or in combination with chemotherapy (chemotherapy with ICI [chemo-ICI]) in these tumors and their immunophenotype have not been systematically described.

METHODS

In this multi-institutional retrospective study, tumor programmed death-ligand 1 (PD-L1) expression and tumor mutational burden (TMB) were evaluated in patients with ROS1-rearranged NSCLC. Time-to-treatment discontinuation (TTD) and objective response rate (ORR) (Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1) were calculated for patients treated with ICI or chemo-ICI in the metastatic setting.

RESULTS

A total of 184 patients were identified. Among 146 assessable cases, PD-L1 expression was less than 1% in 60 (41%), 1% to 49% in 35 (24%), and greater than or equal to 50% in 51 tumors (35%). Of 100 (92%) TMB-assessable tumors, 92 had less than 10 mutations per megabase. TMB was significantly lower for ROS1-rearranged tumors (n = 97) compared with tumors with EGFR (n = 1250) or KRAS alterations (n = 1653) and all other NSCLC tumors (n = 2753) evaluated with Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (median TMB = 2.6 versus 3.5, 7.0, and 6.1 mutations per megabase, p < 0.001). Among patients treated with ICI, median TTD was 2.1 months (95% confidence interval [CI]: 1.0-4.2 mo; n = 28) and ORR 13% (2 of 16 RECIST-assessable; 95% CI: 2%-38%). Among patients treated with chemo-ICI, median TTD was 10 months (95% CI: 4.7-14.1 mo; n = 11) and ORR 83% (5 of 6 RECIST-assessable; 95% CI: 36%-100%). There was no difference in PD-L1 expression (p = 0.91) or TMB (p = 0.83) between responders and nonresponders.

CONCLUSIONS

Most ROS1-rearranged NSCLCs have low PD-L1 expression and TMB. The activity of ICI in these tumors is modest. In contrast, chemo-ICI can achieve meaningful activity.

Clinicopathologic, genomic and protein expression characterization of 356 ROS1 fusion driven solid tumors cases

Based on the approvals of crizotinib and entrectinib by the Food and Drug Administration for the treatment of ROS1 positive nonsmall cell lung cancer (NSCLC), we sought to examine the mutational profile of a variety of solid tumors (excluding sarcomas) with ROS1 fusions that underwent comprehensive genomic profiling. A review of our database was performed to extract all nonsarcoma patients with ROS1 fusions that were discovered by the hybrid capture-based DNA only sequencing assays. We examined the coalterations representing potentially targetable biomarkers, resistance alterations and other alterations in these cases. In addition, we examined the histologic characteristics and protein expression with immunohistochemistry (IHC). From a series of clinically advanced nonsarcoma solid tumors, 356 unique cases with ROS1 fusions included 275 (77.2%) NSCLC and 81 (22.8%) non-NSCLC. Ten novel ROS1 fusions were discovered. Importantly, the NSCLC ROS1 fusion^pos tumors had a higher PD-L1 IHC expression positivity when compared to the NSCLC ROS1 fusion^neg population (P = .012, Chi-squared). The frequency of known and likely anti-ROS1 targeted therapy resistance genomic alterations in NSCLC was 7.3% (20/275) and in non-NSCLC was 4.9% (4/81). Overall, the coalteration profile of ROS1 fusion^pos NSCLC and non-NSCLC was similar with only three genes altered significantly more frequently in non-NSCLC vs NSCLC: TERT, PTEN, APC. In our study, we characterized a large cohort of ROS1 fusion^pos NSCLC and non-NSCLC solid tumors and discovered 10 novel ROS1 fusions.

Cerebrospinal Fluid Penetration and Combination Therapy of Entrectinib for Disseminated ROS1/NTRK-Fusion Positive Pediatric High-Grade Glioma

Targeting oncogenic fusion-genes in pediatric high-grade gliomas (pHGG) with entrectinib has emerged as a highly promising therapeutic approach. Despite ongoing clinical studies, to date, no reports on the treatment of cerebrospinal fluid (CSF) disseminated fusion-positive pHGG exist. Moreover, clinically important information of combination with other treatment modalities such as intrathecal therapy, radiotherapy and other targeted agents is missing. We report on our clinical experience of entrectinib therapy in two CSF disseminated ROS1/NTRK-fusion-positive pHGG cases. Combination of entrectinib with radiotherapy or intrathecal chemotherapy appears to be safe and has the potential to act synergistically with entrectinib treatment. In addition, we demonstrate CSF penetrance of entrectinib for the first time in patient samples suggesting target engagement even upon CSF dissemination. Moreover, in vitro analyses of two novel cell models derived from one case with NTRK-fusion revealed that combination therapy with either a MEK (trametinib) or a CDK4/6 (abemaciclib) inhibitor synergistically enhances entrectinib anticancer effects. In summary, our comprehensive study, including clinical experience, CSF penetrance and in vitro data on entrectinib therapy of NTRK/ROS1-fusion-positive pHGG, provides essential clinical and preclinical insights into the multimodal treatment of these highly aggressive tumors. Our data suggest that combined inhibition of NTRK/ROS1 and other therapeutic vulnerabilities enhances the antitumor effect, which should be followed-up in further preclinical and clinical studies.

Next Generation Sequencing Reveals a Synchronous Trilateral Lung Adenocarcinoma Case with Distinct Driver Alterations of EGFR 19 Deletion or EGFR 20 Insertion or EZR-ROS1 Fusion

OBJECTIVE

Synchronous multiple primary lung cancer (SMPLC) has a reported occurrence from 0.5% to 2% in lung cancer, and the surgical treatment and prognosis were quite diverse. With the discovery of driver mutations in lung adenocarcinoma (ADC), next-generation sequencing (NGS) would provide an explicit answer to the key question, whether individual tumors represent intrapulmonary metastases or independent tumors. Here, we reported a 64-year-old female diagnosed with a synchronous trilateral early-stage ADC with distinct driver alterations.

MATERIALS AND METHODS

NGS test targeting 31 cancer-relevant genes and amplification RNA sequencing (if gene fusion was found on DNA level) were performed on the surgical tumor tissue.

RESULTS

A 64-year-old Chinese female never smoker was found with one nodule in the right upper lobe and two nodules in the right middle lobe through chest computed tomography. The lesions were resected through video-assisted thoracic surgery and diagnosed with stage IA ADC, T1N0M0, in the postoperative pathology. NGS detected three independent driver mutations in three primary sites, respectively, EGFR 19del, EGFR 20ins and ROS1 fusion.

CONCLUSION

This is the first report of a synchronous trilateral early-stage ADC with distinct driver alterations. All individual tumors were independent identified by NGS methodology, which had provided a clear answer to the key question of SMPLC in this case and should be used as a routine genetic test to explore fully pathological diagnosis and more comprehensive oncogenesis information in the early-stage ADC clinical prevention.

ROS1 Fusion Mediates Immunogenicity by Upregulation of PD-L1 After the Activation of ROS1-SHP2 Signaling Pathway in Non-Small Cell Lung Cancer

The drug resistance of first-line crizotinib therapy for ROS proto-oncogene 1, receptor tyrosine kinase (ROS1) fusion non-small cell lung cancer (NSCLC) is inevitable. Whether the administration of immune checkpoint inhibitor (ICI) therapy is suitable for ROS 1 fusion NSCLCs or after the development of crizotinib resistance is still unknown. In this study, five different crizotinib resistant concentration cell lines (HCC78CR1-5) from primary sensitive HCC78 cells were cultured. Ba/F3 cells expressing crizotinib sensitive ROS1 fusion and crizotinib resistant ROS1-G2032R mutation were used to explore the relationship between ROS1 fusion, ROS1-G2032R mutation and programmed death-ligand 1 (PD-L1) expression and the clinical potential of anti-PD-L1 ICI therapy. The signaling pathway net was compared between HCC78 and HCC78CR1-5 cells using RNA sequencing. Anti- PD-L1 ICI therapy was performed on mouse xenograft models with Ba/F3 ROS1 fusion or ROS1-G2032R mutation. HCC78CR1-5 showed more immunogenicity than HCC78 in immune-related pathways. The PD-L1 expression level was remarkably higher in HCC78CR1-5 with ROS1 fusion upregulation than HCC78 primary cell. Furthermore, the expression of PD-L1 was down-regulated by RNA interference with ROS1 siRNAs and up-regulated lower in Ba/F3 ROS1-G2032R resistant mutation than ROS1 fusion. Western blotting analysis showed the ROS1–SHP2 signaling pathway activation in HCC78CR1-5 cells, Ba/F3 ROS1 fusion and ROS1-G2032R resistant mutation. Mouse xenograft models with Ba/F3 ROS1 fusion showed more CD3+PD-1+ T cells both in blood and tissue, and more sensitivity than the cells with Ba/F3 ROS1-G2032R resistant mutation after anti-PD-L1 therapy. Our findings indicate that PD-L1 upregulation depends on ROS1 fusion more than ROS1-G2032R mutation. We share our insights of NSCLCs treatment management into the use of anti-PD-L1 ICI therapy in ROS1 fusion and not in ROS1-G2032R resistant mutation.

Acquired MET D1228N Mutations Mediate Crizotinib Resistance in Lung Adenocarcinoma with ROS1 Fusion: A Case Report

Patients with non-small cell lung cancer (NSCLC) containing ROS1 fusions can have a marked response to the ROS1-targeted tyrosine kinase inhibitors (TKIs), such as crizotinib. Common resistance mechanisms of ROS1-fusion targeted therapy are acquired mutations in ROS1. Along with the use of next-generation sequencing in the clinical management of patients with NSCLC during sequential targeted therapy, many mechanisms of acquired resistance have been discovered in patients with activated tyrosine kinase receptors. Besides acquired resistance mutations, bypass mechanisms of resistance to epidermal growth factor receptor (EGFR)-TKI treatment are common in patients with EGFR mutations. Here we describe a patient with metastatic lung adenocarcinoma with CD74-ROS1 fusion who initially responded to crizotinib and then developed resistance by the acquired mutation of D1228N in the MET kinase domain, which showed short-term disease control for cabozantinib. KEY POINTS: The D1228N point mutation of MET is an acquired mutation for crizotinib resistance. The patient obtained short-term clinical benefit from cabozantinib therapy after resistance to crizotinib. The clinical use of next-generation sequencing could maximize the benefits of precision medicine in patients with cancer.

ROS1-rearranged Non-small Cell Lung Cancer

ROS1-rearranged non-small cell lung cancer (NSCLC) makes up approximately 1% to 2% of all NSCLC, is oncogenically driven by a constitutively activated ROS1 kinase paired with certain fusion partners, and can be detected by several different assays. These patients are initially treated with tyrosine kinase inhibitors (TKIs), which target the activated ROS1 kinase. Eventually these tumors develop resistance to initial TKI treatment through secondary kinase mutations that block TKI binding or activation of bypass signaling pathways, which subvert ROS1 as the driver of the malignancy. Investigation of several TKIs that have shown efficacy in secondary resistant patients is underway.

Successful Treatment of Patients with Refractory High-Grade Serous Ovarian Cancer with GOPC-ROS1 Fusion Using Crizotinib: A Case Report

BACKGROUND

Recently, multiple poly (ADP-ribose) polymerase (PARP) inhibitors have demonstrated excellent efficacy among patients with ovarian cancer with or without BRCA mutations. However, alternative therapeutic options are urgently required for patients who cannot benefit from conventional chemotherapy or PARP inhibitors.

CASE PRESENTATION

A patient with high-grade serous ovarian carcinoma presented to our clinic after developing resistance to chemotherapy. Paired tumor-normal next-generation sequencing (NGS) was performed using peripheral blood to identify potential actionable mutations. NGS revealed the patient harboring a GOPC-ROS1 fusion, which was subsequently verified using a reverse transcription polymerase chain reaction assay. No germline or somatic mutation in BRCA1/2 or mismatch repair genes was detected. Therefore, the patient received crizotinib treatment. A rapid, favorable clinical response (partial response at 1 month) was observed, with further pathological response monitored and evaluated in follow-up interrogation.

CONCLUSION

This study suggested that crizotinib was an off-the-shelf, practical, and ostensibly effective treatment option for patients with ovarian cancer with ROS1 rearrangement. NGS-based genetic testing may guide to plan therapeutic paradigms, and render precision medicine promising in ovarian cancer treatment.

IMPLICATIONS FOR PRACTICE

Despite the previous report of ROS1 fusion in patients with ovarian cancer, it remains unknown whether patients can benefit from targeted therapeutic drugs. This study reports a GOPC-ROS1 fusion identified by next-generation sequencing in a patient with chemotherapy-resistant ovarian cancer. The patient was administered crizotinib and showed rapid, remarkable response. This study suggests that comprehensive sequencing should be offered for patients with ovarian cancer without effective therapeutic strategies, and crizotinib can be used to treat ROS1-rearranged ovarian carcinomas.

Cases of ROS1-rearranged lung cancer: when to use crizotinib, entrectinib, lorlatinib, and beyond?

ROS1-rearranged (also known as ROS1 fusion-positive) non-small-cell lung cancer is an uncommon but distinct molecular subgroup seen in approximately 1–2% of cases. Oncogene addiction due to constitutive ROS1 tyrosine kinase activation has allowed development of molecularly targeted therapies with remarkable anti-tumor activity. Both crizotinib and entrectinib, multitargeted tyrosine kinase inhibitors (TKIs) have now received approval by the FDA for treatment of patients with advanced ROS1-rearranged lung cancers; however, the clinical efficacy and safety of these drugs have been derived from expansion cohorts of single-arm phase I or basket clinical trials with relatively small populations of this clinically and molecularly distinct subgroup. Both drugs lead to high objective response rates (approximately 70–80%) and have manageable side effects, although only entrectinib has potent intracranial efficacy. Lorlatinib is an oral brain-penetrant ALK/ROS1 TKI with activity in both TKI-naïve and some crizotinib-resistant settings (albeit with limited potency against the crizotinib/entrectinib-resistant ROS1-G2032R mutation). We describe cases of advanced ROS1-rearranged lung cancer receiving crizotinib, entrectinib, and/or lorlatinib in first and later line treatment settings to dissect the current state of evidence supporting management decisions for these patients. The next generation ROS1 TKIs (repotrectinib and DS-6051b), owing to their broad activity against kinase mutations including ROS1-G2032R in preclinical studies, hold promise to transform the current treatment paradigm and permit even further gains with regards to long-term outcomes in this subset of patients.

Clinical Utility of Reflex Ordered Testing for Molecular Biomarkers in Lung Adenocarcinoma

INTRODUCTION

In order to standardize and expedite molecular biomarker testing, we implemented reflex ordered testing of targeted gene alterations in newly diagnosed lung adenocarcinomas within our hospital system.

PATIENTS AND METHODS

Reflex ordered testing of specific molecular biomarkers at the time of pathologic diagnosis of lung adenocarcinoma was approved and adopted system-wide in our hospital during 2017. Through institutional review board approval, we retrospectively looked at cohort of patients whose specimens received a diagnosis of lung adenocarcinoma, with molecular biomarker testing performed at Houston Methodist Hospital between 2016 and 2018. We compared average turnaround time (TAT) from 2016 (prior to reflex ordered testing) to 2017 and 2018 (post reflex ordered testing).

RESULTS

Standard molecular testing performed on 39 patients in 2016 had an average TAT of 52.6 days, whereas reflex ordered molecular testing in 2017 yielded an average TAT of 26.5 days (n = 127) and 15.6 days in 2018 (n = 54). The average TAT for reporting of molecular results significantly decreased by 37 days (P = .0002) within our hospital system post adoption of reflex ordered testing for lung adenocarcinoma. Reflex ordered testing also resulted in a higher variant detection rate than standard molecular biomarker ordering practices (48.8% vs. 25.6%; P < .05). Overall, the frequencies and types of variants identified among our cohort were similar to previous reports.

CONCLUSIONS

Reflex ordered testing of molecular biomarkers in lung adenocarcinoma led to significantly decreased TAT within our hospital system and higher detection rates of targeted gene alterations.

ROS1-fusion protein induces PD-L1 expression via MEK-ERK activation in non-small cell lung cancer

Introduction

Despite some of the oncogenic driver mutations that have been associated with increased expression of programmed death-ligand 1 (PD-L1), the correlation between PD-L1 expression and ROS1 fusion in NSCLC cells, especially for those with Crizotinib resistance has not been fully addressed.

Materials and Methods

The expression of PD-L1 in 30 primary NSCLC tumors with/without ROS1-fusion protein was evaluated by immunohistochemical (IHC) analysis. To assess the correlation between ROS1 fusion and PD-L1 expression, we down-regulated ROS1 with RNA interference or specific inhibitor (Crizotinib) in ROS1-fusion positive NSCLC cell line HCC78; or up-regulate ROS1-fusion gene in an immortalized human bronchial epithelial cell line (HBE). Mouse xenograft models were also used to determine the effect of ROS1 expression on PD-L1 expression in vivo. Crizotinib-resistant cell line was generated for measuring the association between Crizotinib resistance and PD-L1 expression.

Results

ROS1-rearrangement in primary NSCLC tumor was significantly associated with up-regulated PD-L1 expression. PD-L1 expression was significantly up-regulated in bronchial epithelial cells after forced expression of ROS1 fusion and was eliminated when HCC78 xenograft mouse models were treated with Crizotinib. We found PD-L1 expression was modulated by MEK-ERK pathway signaling in both parental and Crizotinib-resistant NSCLC cells with ROS1 fusion.

Conclusions

The correlation between ROS1-fusion and PD-L1 overexpression suggested that PD-L1/PD-1 blockade could be the second-line treatment option for the Crizotinib-resistant NSCLC with ROS1 rearrangement.

High Prevalence of Somatic Oncogenic Driver Alterations in Patients With NSCLC and Li-Fraumeni Syndrome

INTRODUCTION

Actionable somatic molecular alterations are found in 15% to 20% of NSCLC in Europe. NSCLC is a tumor observed in patients with germline TP53 variants causing Li-Fraumeni syndrome (LFS), but its somatic molecular profile is unknown.

METHODS

Retrospective study of clinical and molecular profiles of patients with NSCLC and germline TP53 variants.

RESULTS

Among 22 patients with NSCLC and LFS (n = 23 lung tumors), 64% were women, median age was 51 years, 84% were nonsmokers, 73% had adenocarcinoma histological subtype, and 84% were diagnosed with advanced-stage disease. These patients harbored 16 distinct germline TP53 variants; the most common was p.R158H (5/22; three in the same family). Personal and family histories of cancer were reported in 71% and 90% of patients, respectively. In most cases (87%, 13/15), lung cancer was diagnosed with a late onset. Of the 21 tumors analyzed, somatic oncogenic driver mutations were found in 19 of 21 (90%), EGFR mutations in 18 (exon 19 deletion in 12 cases, L858R in three cases, and G719A, exon 20 insertion, and missing mutation subtype, each with one case), and ROS1 fusion in one case. A PI3KCA mutation was concurrently detected at diagnosis in three EGFR exon 19-deleted tumors (3/12). The median overall survival was 37.3 months in 14 patients treated with EGFR inhibitors; seven developed resistance, five (71%) acquired EGFR-T790M mutation, and one had SCLC transformation.

CONCLUSIONS

Driver oncogenic alterations were observed in 90% of the LFS tumors, mainly EGFR mutations; one ROS1 fusion was also observed. The germline TP53 variants and lung cancer carcinogenesis driven by oncogenic processes need further evaluation.

[Clinical features of 54 cases of lung adenocarcinomas with c-ROS oncogene 1 fusion]

Objective: To study the prevalence of c-ros oncogene 1 fusion in lung adenocarcinoma and to evaluate its relationship with clinical characteristics. Methods: We retrospectively analyzed epidermal growth factor receptor (EGFR) mutation, anaplastic lymphoma kinase (ALK) and c-ros oncogene 1 (ROS1) fusion in 1 482 patients with adenocarcinoma from March 2014 to January 2017 in the first affiliated hospital of Zhejiang University. Furthermore, ROS1 fusion positive patients diagnosed between February 2017 and December 2017 were also included in ROS1 positive group. The data of age, sex, smoking history, TNM stage and chest computed tomography were collected by Electronic Medical Record (EMR). The clinical data were compared by the chi-squared test or Mann-Whitney test. Results: Of these 1 482 patients,54 cases were diagnosed with ROS1 rearrangement, including 19 males and 35 females, while 73 cases were diagnosed with ALK rearrangement, including 28 males and 45 females, and 679 cases diagnosed with EGFR mutation including 293 males and 386 females. And there were 676 patients without driven genes mutation. The mean age in ROS1 fusion group (54±12) was lower than EGFR mutation group (60±11, z=-3.982, P<0.001) and WT group (62±10, z=-4.944, P<0.001). Female proportion in ROS1 fusion group (64.8%, 35/54) was higher than WT group (28.4%, 192/676, χ(2)=30.94, P<0.001). Non-smoker percentages in ROS1 fusion group (72.2%, 39/54) was significantly higher than WT group (38.0%,257/676, χ(2)=24.27, P<0.001). ROS1 fusion group was similar to ALK fusion group in sex, age and smoking history, and there were no significant difference in TNM stage among these groups. On chest CT, adenocarcinomas with ROS1 fusion were found to be more peripheral in location (71.4%, 20/28) and solid in density (75%, 21/28), usually with lobulated margins (75.0%, 21/28) and spiculated in contour (57.1%,16/28). Conclusion: In our study lung adenocarcinoma with c-ROS oncogene 1 fusion was a rare subtype lung cancer and was usually detected in young, never smoking, and female patients.

Prevalence of ROS1 fusion in Chinese patients with non-small cell lung cancer

BACKGROUND

The study was conducted to investigate the clinicopathological features and prevalence of ROS1 gene fusion in Chinese patients with non-small cell lung cancer (NSCLC).

METHODS

The presence of ROS1 fusion was assessed by quantitative real-time PCR. Associations between ROS1 fusion and clinical characteristics were analyzed.

RESULTS

In total, 6066 patients with pathologically confirmed NSCLC and ROS1 fusion test results were enrolled. The average age was 60.89 ± 10.60 years and fusion was detected in 157 (2.59%) patients. Fusion frequency was significantly correlated with age, gender, smoking status (all P < 0.001), pathology type (P = 0.017), and lymph node metastasis stage (P = 0.027). ROS1 fusion-positive patients were significantly younger (55.68 ± 11.34 vs. negative 61.02 ± 10.44 years; P < 0.01). Fusion frequency was higher in women (3.71% vs. men 1.81%), never-smokers (3.33% vs. smokers 1.21%), and patients with adenocarcinoma (2.77% vs. squamous lung cancer 0.93%) and at advanced node stages (1.31%, 1.40%, 2.07%, and 3.23% for N0, N1, N2, and N3, respectively). No significant correlation between ROS1 fusion status and pathological stage was found in subgroups classified by pathological, tumor, or metastasis stage (P > 0.05). Age, smoking status, and lymph node stage were statistically significantly correlated with ROS1 fusion frequency (all P < 0.05); gender and pathology type were not significantly correlated with ROS1 fusion status after adjusting for smoking status.

CONCLUSION

An overall ROS1 fusion frequency of 2.59% was confirmed in this study. ROS1 fusion was more prevalent among younger patients, never-smokers, and those at advanced node stages.

Beyond ALK-RET, ROS1 and other oncogene fusions in lung cancer

Fusions of the RET and ROS1 protein tyrosine kinase oncogenes with several partner genes were recently identified as new targetable genetic aberrations in cases of non-small cell lung cancer (NSCLC) lacking activating EGFR, KRAS, ALK, BRAF, or HER2 oncogene aberrations. RET and ROS1 fusion-positive tumors are mainly observed in young, female, and/or never smoking patients. Studies based on in vitro and in vivo (i.e., mouse) models and studies of several fusion-positive patients indicate that inhibiting the kinase activity of the RET and ROS1 fusion proteins is a promising therapeutic strategy. Accordingly, there are several ongoing clinical trials aimed at examining the efficacy of tyrosine kinase inhibitors (TKIs) against RET and ROS1 proteins in patients with fusion-positive lung cancer. Other gene fusions (NTRK1, NRG1, and FGFR1/2/3) that are targetable by existing TKIs have also been identified in NSCLCs. Options for personalized lung cancer therapy will be increased with the help of multiplex diagnosis systems able to detect multiple druggable gene fusions.