ROS1 fusions in Chinese patients with non-small-cell lung cancer

Clinicopathologic characteristics of patients with ROS1 fusion gene in non-small cell lung cancer: a meta-analysis

BACKGROUND

The receptor tyrosine kinase ROS1 is a driver gene in the non-small cell lung cancer (NSCLC) with promising target treatment potential. The clinical features of NSCLC patients harboring ROS1 fusion gene were not fully understood due to small-to-modest sample sizes of these association studies.

METHODS

We systematically searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) from their inception to March 31, 2015. We analyzed the association between ROS1 fusion genes and four common clinical variables, i.e., gender, smoking status, pathological type and clinical stage.

RESULTS

Eighteen studies consisting of 9,898 NSCLC patients were included in this meta-analysis. Pooled results showed that significantly higher rate of ROS1 fusion gene was detected in female NSCLC patients (OR =1.54, 95% CI: 1.02-2.34, P=0.042), patients without a smoking history (OR =3.27, 95% CI: 1.44-7.45, P=0.005), patients with adenocarcinomas NSCLC (OR =10.24, 95% CI: 5.13-20.40, P<0.001), and patients with an advanced clinical stages III-IV (OR =2.57, 95% CI: 1.78-3.71, P<0.001). The pooled prevalence of ROS1 fusion gene was 2.4% (95% CI: 1.8-3.1%) in adenocarcinoma and a significantly lower (0.2%) in non-adenocarcinoma tumors.

CONCLUSIONS

ROS1 rearrangement was more prevalent in female patients, patients without a smoking history, patients with adenocarcinoma, and patients on more advanced stages (stages III to IV).

Targeted therapies for patients with advanced NSCLC harboring wild-type EGFR: what's new and what's enough

Historically, non-small cell lung cancer (NSCLC) is divided into squamous and nonsquamous subtypes based on histologic features. With a growing number of oncogenic drivers being identified in squamous and nonsquamous NSCLC, this malignancy has been recently divided into several distinct subtypes according to the specific molecular alterations. This new paradigm has substantially highlighted the treatment of advanced NSCLC, shifting it from standard chemotherapy according to specific histologic subtypes to targeted therapy according to specific oncogenic drivers. The application of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in NSCLC patients harboring activating EGFR mutations has been a representative model of precise medicine in the treatment of NSCLC. As the role of EGFR-TKIs in routine management of patients with advanced NSCLC has been well established, this review provides an overview of alternative targeted therapy in the treatment of NSCLC, including EGFR-TKIs for patients with wild-type EGFR NSCLC, as well as other targeted agents either clinical available or in early- to late-stage development.

Clinicopathological characteristics and outcomes of ROS1-rearranged patients with lung adenocarcinoma without EGFR, KRAS mutations and ALK rearrangements

Background

c-ros oncogene 1 (ROS1) rearrangement presents one of the newest molecular targets in non-small cell lung cancer (NSCLC). ROS1 rearrangement is predominantly found in adenocarcinoma cases and is exclusive to other oncogenes, such as epidermal growth factor receptor (EGFR), Kirsten rat sarcoma viral oncogene homolog (KRAS), and anaplastic lymphoma kinase (ALK). The aim of this study was to investigate the clinicopathological characteristics and outcomes of ROS1-rearranged patients with lung adenocarcinoma without EGFR and KRAS mutations and ALK rearrangements.

Methods

Wild-type EGFR/KRAS/ALK patients with lung adenocarcinoma were selected from Beijing Chest Hospital. Specimens were conducted in tissue microarrays. ROS1 rearrangement was screened using fluorescence in situ hybridization.

Results

Our study included 127 patients with lung adenocarcinoma without EGFR and KRAS mutations and ALK rearrangements. ROS1 rearrangement was detected in five (3.9%) of the 127 patients. Compared with ROS1-negative patients, the positive rate of ROS1 in female patients was significantly higher than in male patients (9.8% vs. 0.0%, P = 0.009). There were no differences in age, smoking status, stage or histological subtype between ROS1-positive and ROS1-negative patients. No significant difference in survival was detected between the ROS1-positive and ROS1-negative patients.

Conclusions

ROS1 rearrangement is a rare subset of lung adenocarcinoma. In 127 patients with lung adenocarcinoma, 3.9% of ROS1-positive patients with wild-type EGFR/KRAS/ALK were found.

Clinical and the prognostic characteristics of lung adenocarcinoma patients with ROS1 fusion in comparison with other driver mutations in East Asian populations

INTRODUCTION

The prevalence, demographic features, and clinical outcomes of lung adenocarcinoma patients with novel ROS1 oncogenic rearrangement in East Asian populations are not clear. This study aimed to investigate the clinical and prognostic characteristics of lung adenocarcinoma in patients with ROS1 fusion compared with other driver mutations.

METHODS

Multiplex reverse transcription-polymerase chain reaction was used to detect the ROS1 fusion gene in lung adenocarcinoma cases. Immunohistochemistry was used to confirm the expression of ROS1. The demographic data and clinical outcomes of patients with the ROS1 fusion gene were compared with those of patients without the ROS1 fusion gene, including those with the EGFR mutation, EML4-ALK fusion, KRAS mutation, and quadruple-negative patients.

RESULTS

Of 492 patients with lung adenocarcinoma, 12 (2.4%) had the ROS1 fusion gene. Their median age was 45.0 years, significantly younger than that of the ROS1 fusion-negative cohorts (p < 0.001). Acinar (including cribriform) and solid patterns were the two most common histologic subtypes in the ROS1 fusion tumors (7 of 12, 58.3%) and were predominantly seen in CD74-ROS1 fusion tumors (66.7%). There was no significant survival difference between the ROS1 fusion-positive and ROS1 fusion-negative cohorts in surgical group, but ROS1 fusion-positive patients might have worse outcomes than EGFR-mutant patients in the stage IV group.

CONCLUSIONS

The ROS1 fusion gene can be successfully detected in East Asian patients with lung adenocarcinoma using multiplex reverse transcription-polymerase chain reaction. These patients tend to be younger and have characteristic histologic subtypes. Due to the small number of ROS1 fusion patients, the prognostic value of ROS1 fusion need further studies to confirm.

The Frequency and Clinical Implication of ROS1 and RET Rearrangements in Resected Stage IIIA-N2 Non-Small Cell Lung Cancer Patients

To evaluate the frequency and clinicopathological features of ROS1 and RET rearrangements in N2 node positive stage IIIA (IIIA-N2) non-small cell lung cancer (NSCLC) patients, we retrospectively screened 204 cases with a tissue microarray (TMA) panel by fluorescent in situ hybridization (FISH), and confirmed by direct sequencing and immunohistochemistry (IHC). The relationship between ROS1 or RET rearrangements, clinicopathological features, and prognostic factors were analyzed in resected stage IIIA-N2 NSCLC. Of the 204 cases, 4 cases were confirmed with ROS1 rearrangement, but no RET rearrangement was detected. All 4 ROS1-rearranged cases were adenocarcinomas. The predominant pathological type was acinar pattern in ROS1-rearranged tumors, except for 1 case harboring a mixture acinar and mucous tumor cells. Variants of ROS1 rearrangement were SDC4-ROS1 (E2:E32), SDC4-ROS1 (E4:E32) and SDC4-ROS1 (E4:E34). There was no significant association between ROS1 rearrangement and clinicopathological characteristics. In this cohort, multivariate analysis for overall survival (OS) indicated that squamous cell carcinoma and lobectomy were independent predictors of poor prognosis; R0 surgical resection and non-pleural invasion were independent predictors of good prognosis. In resected stage IIIA-N2 NSCLC patients, ROS1-rearranged cases tended to occur in younger patients with adenocarcinomas. The prognosis of resected stage IIIA-N2 is generally considered poor, but patients with ROS1 rearrangement will benefit from the targeted therapy.

Lung cancer molecular epidemiology in China: recent trends

Lung cancer is both the most common diagnosed cancer and the leading cause of cancer related deaths in China. During the past three decades, the incidence and mortality of lung cancer in China are increasing rapidly. According to data from National Central Cancer Registry (NCCR) in 2010, the crude incidence of lung cancer in China was 46.08 per 100,000 population (61.86 per 100,000 men and 29.54 per 100,000 women), with an estimated over 600,000 new diagnosed lung cancer patients (416,333 males and 189,613 females). Meanwhile, the crude mortality of lung cancer in China was 37.00 per 100,000 population (50.04 per 100,000 men and 23.33 per 100,000 women). Consistent with the change in developed countries, adenocarcinoma has become the most predominant histological subtype of lung cancer in China. For the majority advanced non-small-cell lung cancer (NSCLC) patients, especially patients with adenocarcinoma, targeted therapy became increasing important in the treatment. Chinese researcher have done a lot work in terms of lung cancer molecular epidemiology, therefore, in this review, we further summarized the epidemiology of driver genes in NSCLC, hoping to help clinicians to better screen certain driver genes in China for treatment decisions.

Detection of ROS1 gene rearrangement in lung adenocarcinoma: comparison of IHC, FISH and real-time RT-PCR

Aims

To compare fluorescence in situ hybridization (FISH), immunohistochemistry (IHC) and quantitative real-time reverse transcription-PCR (qRT-PCR) assays for detection of ROS1 fusion in a large number of ROS1-positive lung adenocatcinoma (ADC) patients.

Methods

Using IHC analysis, sixty lung ADCs including 16 cases with ROS1 protein expression and 44 cases without ROS1 expression were selected for this study. The ROS1 fusion status was examined by FISH and qRT-PCR assay.

Results

Among 60 cases, 16 (26.7%), 13 (21.7%) and 20 (33.3%) cases were ROS1 positive revealed by IHC, FISH and qRT-PCR, respectively. Using FISH as a standard method for ROS1 fusion detection, the sensitivity and specificity of IHC were 100% and 93.6%, respectively. Three IHC-positive cases, which showed FISH negative, were demonstrated with ROS1 fusion by qRT-PCR analysis. The sensitivity and specificity of qRT-PCR for detection for ROS1 fusion were 100% and 85.1%, respectively. The total concordance rate between IHC and qRT-PCR were 93.3%.

Conclusion

IHC is a reliable and rapid screening tool in routine pathologic laboratories for the identification of suitable candidates for ROS1-targeted therapy. Some ROS1 IHC-positive but FISH-negative cases did harbor the translocation events and may benefit from crizotinib.

Biomarker expression and druggable gene alterations for development of an appropriate therapeutic protocol for pulmonary adenosquamous carcinoma

AIMS

Pulmonary adenosquamous carcinoma (ASC) is more aggressive than adenocarcinoma (AC) and squamous cell carcinoma (SCC). The genetic features and biomarkers of ASC are not well known. Here, we attempted to identify potential therapeutic markers for ASC.

METHODS AND RESULTS

Surgically resected ASC samples from 65 patients were analysed. We examined the expression of β III-tubulin, thymidylate synthase, breast cancer susceptibility gene 1 and ribonucleotide reductase M1 (RRM1); identified mutations in epidermal growth factor receptor (EGFR), KRAS, BRAF and HER2; and detected ALK, ROS1 and RET rearrangements. Gene amplification and expression of EGFR, human epidermal growth factor receptor 2 (HER2), fibroblast growth factor receptor-1 and MET were also examined. β III-Tubulin showed the highest expression (P = 0.002), and its expression was more frequent in the AC than in the SCC component (P = 0.013). RRM1 expression was more frequent in the SCC component (P = 0.046). EGFR and KRAS mutations were detected in both components (21.5 and 10.9%, respectively). ALK and ROS1 rearrangements and MET amplification were detected in both components in one (1.5%) case.

CONCLUSIONS

In ASC, drug response-specific gene alterations could occur in both AC and SCC components, suggesting that patients with confirmed or suspected ASC should undergo further testing for driver gene analyses.

Responses to crizotinib in a patient with c-ros oncogene 1, receptor tyrosine kinase-positive advanced lung adenocarcinoma: A case report

Rearrangements to the c-ros oncogene 1, receptor tyrosine kinase (ROS1) gene are reported in 1–2% of lung adenocarcinomas. These rearrangements are associated with a response to the small-molecule tyrosine kinase inhibitor crizotinib. ROS1 rearrangements can be detected using fluorescence in situ hybridization (FISH), which is considered the gold standard technique in detecting ROS1 rearrangements, and determining whether a patient would respond well to crizotinib treatment. However, FISH is an expensive and time-consuming assay, requiring specialized microscopy equipment and some level of technical expertise. The present report describes the case of a patient with advanced lung adenocarcinoma, who was identified to be negative for ROS-1 rearrangements by FISH, but positive by immunohistochemistry (IHC). The health of the patient improved following treatment with crizotinib. These results indicate that IHC assay could be an alternative option for the detection of ROS1 gene rearrangements.

[Driver genes and its clinical significance in non-small cell lung cancer]

With the development of molecular biology technology and the transforming patterns of drug research, guiding molecular targeted therapy according to the drive gene mutation spectrum in lung cancer has gradually become a reality. Definition of the mutation incidence and whether existing advantage population groups in non-small cell lung cancer (NSCLC) have important guiding significance in clinical practice. The purpose of this paper will draw a summary on the general characteristics, demographic features and clinical significance of driver genes in NSCLC.

[Clinical significance of ROS1 rearrangements in non-small cell lung cancer]

Chromosomal rearrangements involving the ROS1 receptor tyrosine kinase gene have recently been described in multiple malignancies, including non-small cell lung cancer (NSCLC). ROS1 rearrangement defines a new molecular subset of NSCLC with the prevalence of ROS1 rearrangements around 1%-2%. ROS1-positive NSCLCs arise in young never-smokers with adenocarcinoma that are similar to those observed in patients with ALK-rearranged NSCLC. Crizotinib demonstrates in vitro activity and early clinical trial shows marked antitumor activity in ROS1-rearranged patients. The overall response rate is around 56% and the disease control rate at 8 weeks is about 76%. Further understanding the ROS1 fusions in the pathogenesis of NSCLC, methods to detect ROS1 rearrangements, and targeting ROS1-rearranged NSCLC patients with specific kinase inhibitors would lead to an era of personalized medicine.

ROS1 expression and translocations in non-small-cell lung cancer: clinicopathological analysis of 1478 cases

AIMS

Molecular characterization of non-small-cell lung cancer (NSCLC) has revealed multiple druggable mutations for targeted therapies. Recently, chromosomal rearrangements involving c-ros oncogene 1, receptor tyrosine kinase (ROS1) were identified, and patients seem to benefit from crizotinib treatment. The aim of this study was to identify the clinicopathological characteristics of NSCLC with ROS1 expression and translocation.

METHODS AND RESULTS

We screened 1478 NSCLCs with a ROS1-specific antibody, and tested positive cases with FISH. All positive cases were analysed for associated clinicopathological characteristics, including survival and molecular tumour composition. Sixty-eight cases (4.6%) showed ROS1 immunoreactivity, and ROS1 translocations were confirmed in nine cases (0.6%). ROS1 expression was predominantly found in female adenocarcinoma patients, in patients with low T stages, and in association with TTF1 and napsin expression, and certain histomorphological adenocarcinoma patterns (lepidic, acinar, and solid). ROS1 translocations occurred in conjunction with other driver mutations (EGFR, KRAS, and BRAF). ROS1 expression was found to be a stage-independent predictor of favourable survival.

CONCLUSIONS

ROS1 translocations are rare events in resected NSCLCs from Caucasian patients. Immunohistochemical screening for ROS1 expression and clinicopathological parameters, including female sex, early tumour stages, adenocarcinomas with TTF1 and/or napsin expression, and a distinct histomorphological growth pattern, strongly facilitate case enrichment. Molecularly driven multistep concepts might not be optimal for case selection.

RET and other genes: therapeutic targets in lung adenocarcinoma

SUMMARY: 

The RET fusion gene was recently identified as a new druggable driver gene present in 1–2% of lung adenocarcinomas (LADCs). Vandetanib (ZD6474) and cabozantininb (XL184), two RET tyrosine kinase inhibitors approved by US FDA for the therapy of medullary thyroid cancer, have demonstrated therapeutic effectiveness in a few RET fusion-positive LADC patients. Several clinical trials are under way to address the therapeutic effects of RET tyrosine kinase inhibitors, including these two drugs. Multiplex diagnosis of aberrations in druggable driver oncogenes, such as EGFR, ALK, RET, ROS1, HER2/ERBB2, BRAF and others, in clinical samples will facilitate the design of personalized therapies for LADC based on protein kinase inhibitors. The development of therapeutic methods targeting aberrations of other genes, such as chromatin remodeling genes, is necessary to further improve the treatment of LADC.

Prevalence of driver mutations in non-small-cell lung cancers in the People's Republic of China

Lung cancer is a leading cause of cancer-related mortality worldwide and in the People’s Republic of China. Recently, the pathological proportions of the various forms of lung cancer have changed. A shift to a preponderance of adenocarcinoma at the expense of squamous cell carcinoma is observable. Treatment decisions have historically been based on tumor histology, and evolution of our molecular understanding of cancer has led to development of targeted therapeutic agents. It is essential to further understand mutations that drive cancer development (driver mutations) in relevant genes and their effects on cancer cell proliferation and survival. The epidemiology of lung cancer in the People’s Republic of China has been extensively reviewed elsewhere. However, molecular epidemiological data from mainland China are scarce. Consequently, we herein review the prevalence of driver mutations in Chinese patients.

On the relevance of a testing algorithm for the detection of ROS1-rearranged lung adenocarcinomas

OBJECTIVES

ROS1 proto-oncogene translocations define a new molecular subgroup in non-small cell lung cancers (NSCLC) and are associated with a response to the MET/ALK inhibitor, crizotinib. These rearrangements are described in 0.9-1.7% NSCLC, in wild-type EGFR, KRAS and ALK ("triple negative") lung adenocarcinomas. Rapid and efficient identification of these alterations is thus becoming increasingly important.

MATERIALS AND METHODS

In this study, 121 triple negative lung adenocarcinomas were screened by both IHC with the ROS1 D4D6 antibody, and FISH using two commercially available ROS1 break-apart probes. To address a possible cross-reactivity of the ROS1 antibody with other protein kinase receptors, we screened 80 additional cases with known EGFR, KRAS, PI3KCA, BRAF, HER2 mutations or ALK-rearrangement.

RESULTS

We diagnosed 9 ROS1-rearranged adenocarcinomas, with both a positive FISH result (51-87% rearranged nuclei) and a positive IHC staining (2+/3+ cytoplasmic staining). Only one of the ROS1-positive FISH cases was characterized by a classical split pattern, the others showed a variant pattern, most commonly involving a loss of the 5' telomeric probe. Considering a positivity threshold of 2+ stained cells, the sensitivity of the ROS1 D4D6 antibody compared to FISH was 100% and the specificity 96.9%, as two HER2-mutated tumors were positive with D4D6 antibody, without any translocation in FISH. All the ROS1-positive cases were at an advanced stage, arising in never or light smokers. They were mainly solid cribriform and acinar adenocarcinomas, with signet ring cells noted in 5 cases, and calcifications in 3 cases. One positive case was an invasive mucinous carcinoma.

CONCLUSION

Our results show that a screening algorithm based on an IHC detection of ROS1 fusion proteins, confirmed if positive or doubtful by a ROS1 break-apart FISH assay, is pertinent in advanced "triple negative" lung adenocarcinomas, since the prevalence of ROS1-positive cases in this selected population reaches 7.4% in our series.

The frequency and impact of ROS1 rearrangement on clinical outcomes in never smokers with lung adenocarcinoma

BACKGROUND

To determine the frequency and predictive impact of ROS1 rearrangements on treatment outcomes in never-smoking patients with lung adenocarcinoma.

PATIENTS AND METHODS

We concurrently analyzed ROS1 and ALK rearrangements and mutations in the epidermal growth factor receptor (EGFR), and KRAS in 208 never smokers with lung adenocarcinoma. ROS1 and ALK rearrangements were identified by fluorescent in situ hybridization.

RESULTS

Of 208 tumors screened, 7 (3.4%) were ROS1 rearranged, and 15 (7.2%) were ALK-rearranged. CD74-ROS1 fusions were identified in two patients using reverse transcriptase-polymerase chain reaction. The frequency of ROS1 rearrangement was 5.7% (6 of 105) among EGFR/KRAS/ALK-negative patients. Patients with ROS1 rearrangement had a higher objective response rate (ORR; 60.0% versus 8.5%; P = 0.01) and a longer median progression-free survival (PFS; not reached versus 3.3 months; P = 0.008) to pemetrexed than those without ROS1/ALK rearrangement. The PFS to EGFR-tyrosine kinase inhibitors in patients harboring ROS1 rearrangement was shorter than those without ROS1/ALK rearrangement (2.5 versus 7.8 months; P = 0.01).

CONCLUSIONS

The frequency of ROS1 rearrangements in clinically selected patients is higher than that reported for unselected patients, suggesting that ROS1 rearrangement is a druggable target in East-Asian never smokers with lung adenocarcinoma. Given the different treatment outcomes to conventional therapies and availability of ROS1 inhibitors, identification of ROS1 rearrangement can lead to successful treatment in ROS1-rearranged lung adenocarcinomas.