KIF5B-RET fusions in Chinese patients with non-small cell lung cancer

Expression of extracellular HSP90α in pre- and post-treatment samples of driver-gene-negative non-small cell lung cancer

PURPOSE

This study aimed to explore the significance of the expression of pre- and post-treatment eHSP90α in the treatment response evaluation and prognosis of driver-gene-negative non-small cell lung cancer (NSCLC), as well as the significance of eHSP90α expression in the prognosis of immunotherapy.

METHODS

We collected pre-treatment eHSP90α in 330 driver-gene-negative NSCLC patients and analyzed its relationship with efficacy evaluation and prognosis. Survival curves were used to determine their respective critical values and the relationship between eHSP90α expression and OS and PFS was analyzed. Then, univariable and multivariable Cox regression analyses and LASSO multivariable logistic regression analyses were used to establish the prognostic and efficacy evaluation models.

RESULTS

High expression of pre-treatment eHSP90α in driver-gene-negative NSCLC patients is associated with shorter OS. Pre-treatment eHSP90α, immunotherapy, TTF-1, CA125, and age influence OS in NSCLC patients. In the stratified analysis of immunotherapy, pre-treatment eHSP90α in immunotherapy is an independent influencing factor of OS in NSCLC patients, and pre-treatment eHSP90α, age, CA125, and B lymphocytes in non-immunotherapy are independent influencing factors of OS in NSCLC patients. High expression of pre-treatment eHSP90α in NSCLC patients is associated with shorter PFS. Pre-treatment eHSP90α, M1, Ki-67, and immunotherapy are independent influencing factors of PFS in NSCLC patients. In the stratified analysis of immunotherapy, pre-treatment eHSP90α and CEA in immunotherapy are independent influencing factors of PFS in NSCLC patients, and pre-treatment eHSP90α, M1, Ki-67, CA125, Th/Ts, and age in non-immunotherapy are independent factors affecting PFS in NSCLC patients. Pre-treatment eHSP90α was one of the influencing factors in the efficacy evaluation model.

CONCLUSIONS

The expression of pre-treatment eHSP90α has significant significance for the prognosis and efficacy evaluation of driver-gene-negative NSCLC.

Diagnosis, Treatment Patterns, and Outcomes in Real-World Patients with RET Fusion-Positive Non-small Cell Lung Cancer in China

INTRODUCTION

Epidemiological studies on non-small cell lung cancer (NSCLC) have noted RET fusions as an oncogenic driver. However, real-world data on RET biomarker testing and treatment patterns in China remain limited. This study aimed to examine demographics, clinical and molecular features, and RET testing and treatment patterns and outcomes in patients with RET fusion-positive NSCLC.

METHODS

Utilizing real-world data from the Chinese Multi-center Lung Cancer Precision Medicine Registry, this retrospective cohort study focused on Chinese patients diagnosed with RET fusion-positive NSCLC between January 1, 2016, and November 30, 2021. The cohort was divided into early-stage and advanced-stage subgroups. Demographics, clinical and molecular profiles, treatment received, and outcomes including real-world event free survival (rwEFS), real-world progression free survival (rwPFS), and overall survival (OS) were assessed.

RESULTS

The study included 121 patients with RET fusion-positive NSCLC, comprising 80 early-stage and 58 advanced-stage patients. High biomarker testing rates were observed at diagnosis (75% for early-stage, 78% for advanced-stage). RET testing was often conducted via tissue samples (95.9%) and next-generation sequencing (89.3%). KIF5B (57.0%) and CCDC6 (20.7%) were the most common gene fusion partners. The most frequent oncogenic mutations were TP53 (15.7%) and EGFR (6.6%). Platinum-based chemotherapy was the most common first-line treatment among advanced-stage patients. Median rwPFS was 9.22 months for advanced-stage patients on first-line chemotherapy, and median OS was 30.7 months for all advanced-stage patients. The 2-year rwEFS rate for early-stage patients was 86.0%, with a median OS of 91.9 months.

CONCLUSIONS

The study observed high biomarker testing rates at initial diagnosis for early- and advanced-stage RET fusion-positive NSCLC patients in China. The heterogeneous treatment pattern of advanced patients suggests the need for more precise, evidence-based treatment to guide clinical decisions. Given the existing therapeutic regimens fall short of adequately addressing treatment needs, targeted therapies are essential to improve outcomes.

Prognostic Indicators for Precision Treatment of Non-Small Cell Lung Carcinoma

Non-small cell lung cancer (NSCLC) has established predictive biomarkers that enable decisions on treatment regimens for many patients. However, resistance to therapy is widespread. It is therefore essential to have a panel of molecular biomarkers that may help overcome therapy resistance and prevent adverse effects of treatment. We performed in silico analysis of NSCLC prognostic indicators, separately for adenocarcinomas and squamous carcinomas, by using The Cancer Genome Atlas (TCGA) and non-TCGA data sources in cBioPortal as well as UALCAN. This review describes lung cancer biology, elaborating on the key genetic alterations and specific genes responsible for resistance to conventional treatments. Importantly, we examined the mechanisms associated with resistance to immune checkpoint inhibitors. Our analysis indicated that a robust prognostic biomarker was lacking for NSCLC, especially for squamous cell carcinomas. In this work, our screening uncovered previously unidentified prognostic gene expression indicators, namely, MYO1E, FAM83 homologs, and DKK1 for adenocarcinoma, and FGA and TRIB1 for squamous cell carcinoma. It was further observed that overexpression of these genes was associated with poor prognosis. Additionally, FAM83 homolog and TRIB1 unexpectedly harbored copy number amplifications. In conclusion, this study elucidated novel prognostic indicators for NSCLC that may serve as targets to overcome therapy resistance toward improved patient outcomes.

RET Inhibitors in RET Fusion-Positive Lung Cancers: Past, Present, and Future

While activating RET fusions are identified in various cancers, lung cancer represents the most common RET fusion-positive tumor. The clinical drug development of RET inhibitors in RET fusion-positive lung cancers naturally began after RET fusions were first identified in patient tumor samples in 2011, and thereafter paralleled drug development in RET fusion-positive thyroid cancers. Multikinase inhibitors were initially tested with limited efficacy and substantial toxicity. RET inhibitors were then designed with improved selectivity, central nervous system penetrance, and activity against RET fusions and most RET mutations, including resistance mutations. Owing their success to these rationally designed features, the first-generation selective RET tyrosine kinase inhibitors (TKIs) had higher response rates, more durable disease control, and an improved safety profile compared to the multikinase inhibitors. This led to lung and thyroid cancer, and later tumor-agnostic regulatory approvals. While next-generation RET TKIs were designed to abrogate uncommon on-target (e.g., solvent front mutation) resistance to selpercatinib and pralsetinib, many of these drugs lacked the selectivity of the first-generation TKIs, raising the question of what the future holds for drug development in RET-dependent cancers.

RET Fusion Testing in Patients With NSCLC: The RETING Study

Introduction

RET inhibitors with impressive overall response rates are now available for patients with NSCLC, yet the identification of RET fusions remains a difficult challenge. Most guidelines encourage the upfront use of next-generation sequencing (NGS), or alternatively, fluorescence in situ hybridization (FISH) or reverse transcriptase-polymerase chain reaction (RT-PCR) when NGS is not possible or available. Taken together, the suboptimal performance of single-analyte assays to detect RET fusions, although consistent with the notion of encouraging universal NGS, is currently widening some of the clinical practice gaps in the implementation of predictive biomarkers in patients with advanced NSCLC.

Methods

This situation prompted us to evaluate several RET assays in a large multicenter cohort of RET fusion-positive NSCLC (n = 38) to obtain real-world data. In addition to RNA-based NGS (the criterion standard method), all positive specimens underwent break-apart RET FISH with two different assays and were also tested by an RT-PCR assay.

Results

The most common RET partners were KIF5B (78.9%), followed by CCDC6 (15.8%). The two RET NGS-positive but FISH-negative samples contained a KIF5B(15)-RET(12) fusion. The three RET fusions not identified with RT-PCR were AKAP13(35)-RET(12), KIF5B(24)-RET(9) and KIF5B(24)-RET(11). All three false-negative RT-PCR cases were FISH-positive, exhibited a typical break-apart pattern, and contained a very high number of positive tumor cells with both FISH assays. Signet ring cells, psammoma bodies, and pleomorphic features were frequently observed (in 34.2%, 39.5%, and 39.5% of tumors, respectively).

Conclusions

In-depth knowledge of the advantages and disadvantages of the different RET testing methodologies could help clinical and molecular tumor boards implement and maintain sensible algorithms for the rapid and effective detection of RET fusions in patients with NSCLC. The likelihood of RET false-negative results with both FISH and RT-PCR reinforces the need for upfront NGS in patients with NSCLC.

RET-Altered Cancers-A Tumor-Agnostic Review of Biology, Diagnosis and Targeted Therapy Activity

RET alterations, such as fusions or mutations, drive the growth of multiple tumor types. These alterations are found in canonical (lung and thyroid) and non-canonical (e.g., gastrointestinal, breast, gynecological, genitourinary, histiocytic) cancers. RET alterations are best identified via comprehensive next-generation sequencing, preferably with DNA and RNA interrogation for fusions. Targeted therapies for RET-dependent cancers have evolved from older multikinase inhibitors to selective inhibitors of RET such as selpercatinib and pralsetinib. Prospective basket trials and retrospective reports have demonstrated the activity of these drugs in a wide variety of RET-altered cancers, notably those with RET fusions. This paved the way for the first tumor-agnostic selective RET inhibitor US FDA approval in 2022. Acquired resistance to RET kinase inhibitors can take the form of acquired resistance mutations (e.g., RET G810X) or bypass alterations.

Intracranial Activity of Selpercatinib in Chinese Patients With Advanced RET Fusion-Positive Non-Small-Cell Lung Cancer in the Phase II LIBRETTO-321 Trial

PURPOSE

Selpercatinib, a highly selective, potent RET inhibitor with CNS activity, demonstrated sustained antitumor responses and intracranial activity in patients with RET-altered advanced non-small-cell lung cancer (NSCLC) in the global LIBRETTO-001 and Chinese LIBRETTO-321 trials. We report a prospective case series based on updated data from patients with brain metastases at baseline in LIBRETTO-321.

MATERIALS AND METHODS

We included patients with advanced NSCLC and brain metastasis with a centrally confirmed KIF5B/CCDC6/NCOA4-RET fusion. Patients with previously treated or untreated CNS metastases were included if asymptomatic or neurologically stable. Patients received oral selpercatinib 160 mg, twice daily, until progression. Objective systemic and intracranial response was independently assessed per RECIST v1.1. The data cutoff (DCO) was March 31, 2022.

RESULTS

In total, 8/26 (31%) patients were included: 1/8 (13%) had previous brain surgery but no previous systemic therapy and 3/8 (38%) had received brain radiotherapy. Best overall systemic response was partial response (PR) in 6/8 patients (75%) and stable disease (SD) in 2/8 (25%). Among patients with measurable baseline CNS lesions, 4/5 (80%) achieved a confirmed intracranial response (3/5 PRs and 1/5 complete response [CR]). The best overall intracranial response was CR in 3/8 (38%), PR in 3/8 (38%), and SD in 1/8 (13%) and nonprogressive disease/non-CR in 1/8 (13%); 2/8 patients (25%) had CNS-only disease progression. The duration of treatment was 2.8-24.0 months, and 5/8 patients (63%) had treatment ongoing at DCO. Of 8 patients, 5 (63%) had grade ≥3 treatment-related adverse events (TRAEs) requiring dose modification. There were no treatment discontinuations because of TRAEs.

CONCLUSION

Selpercatinib demonstrated clinically meaningful and durable intracranial activity in Chinese patients with brain metastases from RET-altered NSCLC, consistent with the global LIBRETTO-001 trial.

Genomic landscape of 891 RET fusions detected across diverse solid tumor types

In this study, we report the clinicopathologic and genomic profiles of 891 patients with RET fusion driven advanced solid tumors. All patient samples were tested using a tissue-based DNA hybrid capture next generation sequencing (NGS) assay and a subset of the samples were liquid biopsies tested using a liquid-based hybrid capture NGS assay. RET fusions were found in 523 patients with NSCLC and in 368 patients with other solid tumors. The two tumor types with the highest number of RET fusion were lung adenocarcinoma and thyroid papillary carcinoma, and they had a prevalence rate 1.14% (455/39,922) and 9.09% (109/1199), respectively. A total of 61 novel fusions were discovered in this pan-tumor cohort. The concordance of RET fusion detection across tumor types among tissue and liquid-based NGS was 100% (8/8) in patients with greater than 1% composite tumor fraction (cTF). Herein, we present the clinicopathologic and genomic landscape of a large cohort of RET fusion positive tumors and we observed that liquid biopsy-based NGS is highly sensitive for RET fusions at cTF ≥1%.

Non-small cell lung cancer in China

In China, lung cancer is a primary cancer type with high incidence and mortality. Risk factors for lung cancer include tobacco use, family history, radiation exposure, and the presence of chronic lung diseases. Most early-stage non-small cell lung cancer (NSCLC) patients miss the optimal timing for treatment due to the lack of clinical presentations. Population-based nationwide screening programs are of significant help in increasing the early detection and survival rates of NSCLC in China. The understanding of molecular carcinogenesis and the identification of oncogenic drivers dramatically facilitate the development of targeted therapy for NSCLC, thus prolonging survival in patients with positive drivers. In the exploration of immune escape mechanisms, programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitor monotherapy and PD-1/PD-L1 inhibitor plus chemotherapy have become a standard of care for advanced NSCLC in China. In the Chinese Society of Clinical Oncology's guidelines for NSCLC, maintenance immunotherapy is recommended for locally advanced NSCLC after chemoradiotherapy. Adjuvant immunotherapy and neoadjuvant chemoimmunotherapy will be approved for resectable NSCLC. In this review, we summarized recent advances in NSCLC in China in terms of epidemiology, biology, molecular pathology, pathogenesis, screening, diagnosis, targeted therapy, and immunotherapy.

A Single-Institute Experience with C-ros Oncogene 1 Translocation in Non-Small Cell Lung Cancers in Taiwan

(1) Background: The C-ros oncogene 1 (ROS1) gene translocation is an important biomarker for selecting patients for crizotinib-targeted therapy. The aim of this study was to understand the incidence, diagnostic algorithm, clinical course and objective response to crizotinib in ROS1 translocated lung non-small cell lung cancers (NSCLCs) in Taiwan. (2) Methods: First, we retrospectively studied the ROS1 status in 100 NSCLC samples using break-apart fluorescent in situ hybridization (FISH) and immunohistochemical (IHC) staining to establish a diagnostic algorithm. Then, we performed routine ROS1 IHC tests in 479 NSCLCs, as crizotinib was available from 2018 in Taiwan. We analyzed the objective response rate and the survival impact of crizotinib. (3) Results: Four ROS1 translocations were clustered in epidermal growth factor receptor (EGFR) wild-type adenocarcinomas but not in cases with EGFR mutations. Strong ROS1 expression was positively correlated with ROS1 translocation (p < 0.001). NSCLCs with ROS1 translocation had a poor prognosis compared to those without ROS1 translocation (p = 0.004) in the pre-crizotinib stage. Twenty NSCLCs were detected with ROS1 translocation in 479 wild-type EGFR specimens from 2018. Therefore, the incidence of ROS1 translocation is approximately 4.18% in EGFR wild-type NSCLCs. In these 20 ROS1 translocation cases, 19 patients received crizotinib treatment, with an objective response rate (ORR) of 78.95% (confidence interval = 69.34% to 88.56%), including 1 complete response, 14 partial responses, 3 stable cases and 1 progressive case. Overall survival and progression-free survival were better in the 19 ROS1-translocated NSCLCs of the prospective group with crizotinib treatment than the four ROS1-translocated NSCLCs of the retrospective group without crizotinib treatment. (4) Conclusions: ROS1-translocated NSCLCs had a poor prognosis and could have a beneficial outcome with crizotinib.

Efficacy and safety of selpercatinib in Chinese patients with advanced RET fusion-positive non-small-cell lung cancer: a phase II clinical trial (LIBRETTO-321)

Introduction:

Oncogenic alterations in RET occur in 1–2% of non-small-cell lung cancers (NSCLCs). The efficacy and safety of the first-in-class, highly selective, and potent RET inhibitor selpercatinib in Chinese patients with RET fusion-positive NSCLC remains unknown.

Methods:

In this open-label, multicenter, phase II study (NCT04280081), patients with advanced RET-altered solid tumors received selpercatinib (160 mg orally twice daily) in a 28-day cycle. The primary endpoint was independent review committee (IRC)-assessed objective response rate (ORR; Response Evaluation Criteria in Solid Tumors v1.1). Secondary endpoints included duration of response, central nervous system (CNS) response, and safety. Efficacy against NSCLC was assessed in the primary analysis set (PAS; centrally confirmed RET status) and in all enrolled patients with NSCLC.

Results:

Of 77 enrolled patients, 47 had RET fusion-positive NSCLC. After 9.7 months of median follow-up, IRC-assessed ORR in the PAS (n = 26) was 69.2% [95% confidence interval (CI), 48.2–85.7] and 94.4% of responses were ongoing; the ORR was 87.5% and 61.1% in treatment-naïve and pre-treated patients, respectively. IRC-assessed ORR in all patients with NSCLC (n = 47) was 66.0% (95% CI, 50.7–79.1). Among five patients with measurable CNS metastases at baseline, four (80%) achieved an IRC-assessed intracranial response. In the safety population (n = 77), most treatment-emergent adverse events (TEAEs) were grade 1 or 2. The most common grade ⩾3 TEAE was hypertension (19.5%). Three (3.9%) patients discontinued therapy due to treatment-related AEs; no deaths occurred due to treatment-related AEs.

Conclusion:

Selpercatinib, with potent and durable antitumor activity including intracranial activity, was well tolerated in Chinese patients with RET fusion-positive NSCLC, consistent with LIBRETTO-001 (ClinicalTrials.gov: NCT04280081).

Diagnostic, Predictive, and Prognostic Biomarkers in Non-Small Cell Lung Cancer (NSCLC) Management

Lung cancer is the leading cause of cancer-related deaths worldwide. Despite growing efforts for its early detection by screening populations at risk, the majority of lung cancer patients are still diagnosed in an advanced stage. The management of lung cancer has dramatically improved in the last decade and is no longer based on the "one-fits-all" paradigm or the general histological classification of non-small cell versus small cell lung cancer. Emerging options of targeted therapies and immunotherapies have shifted the management of lung cancer to a more personalized treatment approach, significantly influencing the clinical course and outcome of the disease. Molecular biomarkers have emerged as valuable tools in the prognosis and prediction of therapy response. In this review, we discuss the relevant biomarkers used in the clinical management of lung tumors, from diagnosis to prognosis. We also discuss promising new biomarkers, focusing on non-small cell lung cancer as the most abundant type of lung cancer.

Analytical Accuracy of RET Fusion Detection by Break-Apart Fluorescence In Situ Hybridization

CONTEXT.—

RET gene fusions are oncogenic drivers in nonsmall cell lung cancer and nonmedullary thyroid cancer. Selpercatinib (RETEVMO), a targeted inhibitor of RET, was approved by the US Food and Drug Administration for the treatment of RET fusion-positive nonsmall cell lung cancer and nonmedullary thyroid cancer emphasizing the need for rapid and accurate diagnosis of RET fusions. Fluorescence in situ hybridization (FISH) has been used to detect gene rearrangements, but its performance detecting RET rearrangements is understudied.

OBJECTIVE.—

To validate and describe the performance of Abbott Molecular RET break-apart FISH probes for detecting RET rearrangements.

DESIGN.—

A training set with RET fusion-positive (13) and RET fusion-negative nonsmall cell lung cancer and nonmedullary thyroid cancer samples (12) was used to establish criteria for FISH scoring. The scoring criteria was then applied to a larger validation set of samples (96).

RESULTS.—

A cutoff of 19% or more positive nuclei by FISH was established in the training set and determined by the mean ±3 SD. The validation set was tested using Abbott Molecular RET break-apart FISH compared with sequencing. With this cutoff, a sensitivity of 86% (12 of 14) and specificity of 99% (81 of 82) was achieved. Bootstrapping showed sensitivity could be optimized by using a greater than 13% cutoff with indeterminate samples of 13% to 18% abnormal nuclei requiring confirmation by an orthogonal method. Using this 3-tier scoring system sensitivity increased to 100% (14 of 14) and specificity was 96% (79 of 82).

CONCLUSIONS.—

Abbott Molecular break-apart FISH probes can be used to detect RET fusions. Laboratories can optimize cutoffs and/or testing algorithms to maximize sensitivity and specificity to ensure appropriate patients receive effective, timely therapy.

Selpercatinib in RET fusion-positive non-small-cell lung cancer (SIREN): a retrospective analysis of patients treated through an access program

INTRODUCTION

Rearranged during transfection (RET) gene fusions are rare genetic drivers in non-small cell lung cancer (NSCLC). Selective RET-inhibitors such as selpercatinib have shown therapeutic activity in early clinical trials; however, their efficacy in the real-world setting is unknown.

METHODS

A retrospective efficacy and safety analysis was performed on data from RET fusion-positive NSCLC patients who participated in a selpercatinib access program (named patient protocol) between August 2019 and January 2021.

RESULTS

Data from 50 patients with RET fusion-positive advanced NSCLC treated with selpercatinib at 27 centers in 12 countries was analyzed. Most patients were Non-Asian (90%), female (60%), never-smokers (74%), with a median age of 65 years (range, 38-89). 32% of the patients had known brain metastasis at the time of selpercatinib treatment. Overall, 13 patients were treatment-naïve, while 37 were pretreated with a median of three lines of therapy (range, 1-8). The objective response rate (ORR) was 68% [95% confidence interval (CI), 53-81] in the overall population. The disease control rate was 92%. The median progression-free survival was 15.6 months (95% CI, 8.8-22.4) after a median follow-up of 9 months. In patients with measurable brain metastases (n = 8) intracranial ORR reached 100%. In total, 88% of patients experienced treatment-related adverse events (TRAEs), a large majority of them being grade 1 or 2. The most common grade ⩾ 3 TRAEs were increased liver enzyme levels (in 10% of patients), prolonged QTc time (4%), abdominal pain (4%), hypertension (4%), and fatigue/asthenia (4%). None of patients discontinued selpercatinib treatment for safety reasons. No new safety concerns were observed, nor where there any treatment-related death.

CONCLUSIONS

In this real-world setting, the selective RET-inhibitor selpercatinib demonstrated durable systemic and intracranial antitumor activity in RET fusion-positive NSCLC and was well tolerated.

Updates in the molecular pathology of non-small cell lung cancer

An understanding of the molecular pathology of non-small cell lung cancer (NSCLC) is important for pathologists as molecular characterization is now required for treatment decisions in advanced stage disease. While assessment for EGFR mutations, ALK and ROS1 fusions, and in some countries BRAF mutations, is now standard practice, other oncogenic mutations are also emerging that may impact routine clinical practice including alterations involving KRAS, NTRK, RET, MET and HER2. In addition, molecular pathology alterations of NSCLC are associated with responses to immune checkpoint therapy and are being increasingly investigated. Finally, specific molecular pathological alterations define some rarer subtypes of NSCLC such as salivary gland tumours, NUT carcinoma and SMARCA4-deficient undifferentiated tumour, and an understanding of the molecular pathology is important for their accurate diagnosis. In this review, the molecular pathology of NSCLC is discussed with a focus on clinically relevant molecular alterations.

Practical Considerations Relating to Routine Clinical Biomarker Testing for Non-small Cell Lung Cancer: Focus on Testing for RET Fusions

For patients with advanced non–small cell lung cancer, genomic profiling of tumors to identify potentially targetable alterations and thereby inform treatment selection is now part of standard care. While molecular analyses are primarily focused on actionable biomarkers associated with regulatory agency-approved therapies, there are a number of emerging biomarkers linked to investigational agents in advanced stages of clinical development will become approved agents. A particularly timely example is the reported data and US Food and Drug Administration approval of highly specific small molecule inhibitors of the proto-oncogene tyrosine-protein kinase receptor RET indicate that testing for tumor RET gene fusions in patients with NSCLC has become clinically important. As the number of biomarkers to be tested in NSCLC grows, it becomes increasingly important to optimize and prioritize the use of biopsy tissue, in order to both continue to allow accurate histopathological diagnosis and also to support concurrent genomic profiling to identify perhaps relatively uncommon genetic events. In order to provide practical expert consensus guidance to optimize processes facilitating genomic testing in NSCLC and to overcome barriers to access and implementation, a multidisciplinary advisory board was held in New York, on January 30, 2019. The panel comprised physicians involved in sample procurement (interventional radiologists and a thoracic surgeon), surgical pathologists specializing in the lung, molecular pathologists, and thoracic oncologists. Particular consideration was given to the key barriers faced by these experts in establishing institutional genomic screening programs for NSCLC. Potential solutions have been devised in the form of consensus opinions that might be used to help resolve such issues.

Comprehensive genomic profile of Chinese lung cancer patients and mutation characteristics of individuals resistant to icotinib/gefitinib

Lung cancer is the leading causes of cancer-related death worldwide. Precise treatment based on next-generation sequencing technology has shown advantages in the diagnosis and treatment of lung cancer. This cohort study included 371 lung cancer patients. The lung cancer subtype was related to the smoking status and sex of the patients. The most common mutated genes were TP53 (62%), EGFR (55%), and KRAS (11%). The mutation frequencies of EGFR, TP53, PIK3CA, NFE2L2, KMT2D, FGFR1, CCND1, and CDKN2A were significantly different between lung adenocarcinoma and lung squamous cell carcinoma. We identified the age-associated mutations in ALK, ERBB2, KMT2D, RBM10, NRAS, NF1, PIK3CA, MET, PBRM1, LRP2, and CDKN2B; smoking-associated mutations in CDKN2A, FAT1, FGFR1, NFE2L2, CCNE1, CCND1, SMARCA4, KEAP1, KMT2C, and STK11; tumor stage-associated mutations in ARFRP1, AURKA, and CBFB; and sex-associated mutations in EGFR. Tumor mutational burden (TMB) is associated with tumor subtype, age, sex, and smoking status. TMB-associated mutations included CDKN2A, LRP1B, LRP2, TP53, and EGFR. EGFR amplification was commonly detected in patients with acquired lcotinib/gefitinib resistance. DNMT3A and NOTCH4 mutations may be associated with the benefit of icotinib/gefitinib treatment.

New Targets in Lung Cancer (Excluding EGFR, ALK, ROS1)

PURPOSE OF REVIEW

Over the last two decades, the identification of targetable oncogene drivers has revolutionized the therapeutic landscape of non-small cell lung cancer (NSCLC). The extraordinary progresses made in molecular biology prompted the identification of several rare molecularly defined subgroups. In this review, we will focus on the novel and emerging actionable oncogenic drivers in NSCLC.

RECENT FINDINGS

Recently, novel oncogene drivers emerged as promising therapeutic targets besides the well-established EGFR mutations, and ALK/ROS1 rearrangements, considerably expanding the list of potential exploitable genetic aberrations. However, the therapeutic algorithm in these patients is far less defined. The identification of uncommon oncogene drivers is reshaping the diagnostic and therapeutic approach to NSCLC. The introduction of novel highly selective inhibitors is expanding the use of targeted therapies to rare and ultra-rare subsets of patients, further increasing the therapeutic armamentarium of advanced NSCLC.

Targeted Therapy For RET-Rearranged Non-Small Cell Lung Cancer: Clinical Development And Future Directions

Approximately 1-2% of unselected patients with Non-small Cell Lung Cancer (NSCLC) harbor RET rearrangements resulting in enhanced cell survival and proliferation. The initial treatment strategy for RET rearranged NSCLC has been multi-target tyrosine kinase inhibition. With overall response rates (ORR) of 16-53% and a median progression-free survival (PFS) of 4.5-7.3 months these outcomes are clearly inferior to the efficacy outcomes of selective tyrosine kinase inhibitors (TKI) in other oncogene-addicted NSCLC. Additionally, multi-kinase inhibition in RET-driven NSCLC patients showed concerning rates of high-grade toxicity, mainly induced by anti-VEGFR-kinase activity. Novel selective RET inhibitors like BLU-667, LOXO-292 and RXDX-105 have been recently investigated in early phase clinical trials showing promising efficacy with a manageable toxicity profile.

KIF5B-RET fusion gene and its correlation with clinicopathological and prognostic features in lung cancer: a meta-analysis

Background

The KIF5B-RET fusion gene is a novel oncogene that has been observed in a subset of lung cancers in recent years. However, the results of related epidemiological studies remain unclear. Thus, a meta-analysis was conducted to evaluate the correlation of KIF5B-RET expression based on RT-PCR detection with clinicopathological features and prognosis of lung cancer.

Methods

The PubMed, Google Scholar, Wiley Online, SpringerLink and Chinese National Knowledge Infrastructure databases were searched to identify the eligible studies. The association of the occurrence ofKIF5B-RETfusion gene in lung cancer with age, gender, smoking status, histology type, differentiation and TNM stage was analyzed. HR, overall survival (OS) and progression-free survival (PFS) were used to describe the prognosis of patients with lung cancer. The OR and 95% CI were calculated to assess the correlations. Random- and fixed-effects models were used to analyze the data.

Results

A total of 13 studies, which included 8,859 lung cancer patients, were included in the study based on the inclusion criteria. A total of 121 patients with positiveKIF5B-RETfusion gene status were detected, with a positive expression rate of 1.36%. KIF5B-RET fusion gene status was identified at significantly higher frequencies in female (OR=0.67, 95% CI=0.48-0.94) than male patients, and the same trend was found in young (<60 years) patients (OR=0.08, 95% CI=0.01-0.45) compared with old patients (≥60 years). No differences were found in the TNM stage, histology, differentiation and smoking. Based on the prognosis, no difference was found between the status of the positive and negativeKIF5B-RET fusion genes in OS and PFS of patients.

Conclusion

The KIF5B-RETfusion gene occurred predominantly in young female patients with lung cancer. However, the relationship between the expression of the fusion gene and the prognosis of lung patients remains unclear.

Discovery Stories of RET Fusions in Lung Cancer: A Mini-Review

In 2004, a chemical inhibitor of the kinase activity of EGFR was reported to be effective in a subset of lung cancer patients with activating somatic mutations of EGFR. It remained unclear, however, whether kinase fusion genes also play a major role in the pathogenesis of lung cancers. The discovery of the EML4-ALK fusion kinase in 2007 was a breakthrough for this situation, and kinase fusion genes now form a group of relevant targetable oncogenes in lung cancer. In this mini-review article, the discovery of REarrangement during Transfection fusions, the third kinase fusion gene in lung cancer, is briefly described.

RET fusion in advanced non-small-cell lung cancer and response to cabozantinib: A case report

RATIONALE

Lung cancer is a series of gene-driven disease. EGFR, ALK, and ROS1 are 3 major driver genes that play an important role in lung cancer development and precision management. Additionally, rare genetic alterations continue to be discovered and may become novel targets for therapy. The RET gene is one of such rare genetic alteration of non-small cell lung cancer (NSCLC). In this report, we present a RET-positive case that benefited from cabozantinib treatment.

PATIENT CONCERN

A 50-year-old male patient was diagnosed with lung adenocarcinoma 2 years ago, at that time he received palliative surgery of pulmonary carcinoma and completed 4 cycles of chemotherapy with gemcitabine and cisplatin. Six months later, he was hospitalized in our cancer center due to the disease recurrence, presenting with pleural metastasis.

DIAGNOSIS

Gene alteration was examined using the intraoperative specimen by PCR method, and KIF5B/RET gene fusion was detected. Therefore, the patient was diagnosed with late-stage lung adenocarcinoma with RET gene mutation.

INTERVENTIONS

The patient received treatment with cabozantinib from June 2017.

OUTCOMES

Cabozantinib was administered (140 mg orally, once daily) for approximate 9 months, and his disease achieved stable disease (SD). During that period, there were no severe adverse events (AE), except for a grade II rash (CTCAE 4.0).

LESSONS

We found that the RET fusion gene is a novel driver molecular of lung adenocarcinoma in patients without common mutations in such genes as EGFR, ALK, and ROS1. This case report supports a rationale for the treatment of lung adenocarcinoma patients with a RET fusion and provides alternative treatment options for these types of NSCLC patients.

Clinical Characteristics and Molecular Patterns of RET-Rearranged Lung Cancer in Chinese Patients

RET rearrangement has been proven as an oncogenic driver in patients with lung cancer. However, the prevalence, clinical characteristics, molecular features, and therapeutic options in RET-rearranged patients remain unclear, especially in Chinese lung cancer patients. We retrospectively collected 6,125 Chinese lung cancer patients who have been profiled using next-generation sequencing (NGS). The clinical demographics and molecular features of RET rearrangement-positive patients were analyzed. RET rearrangements were identified in 84 patients with a proportion of 1.4% in our cohort. The median age at diagnosis was 58 years, and it mainly occurred in females with adenocarcinoma histology. KIF5B-RET was the most frequent fusion type and accounted for 53.8% (57/106) of all RET fusions identified, with K15-R12 as the most frequent variant (71.9%). Among 47 RET⁺ patients profiled with larger panels, 72.3% (34/47) harbored concurrent alterations. TP53 ranked as the most common concurrent alteration, and concomitant EGFR oncogenic alterations were identified in seven patients. Moreover, an adenocarcinoma patient harboring concurrent RET fusion and EGFR L858R responded to combinatorial treatment of cabozantinib and osimertinib, with a progression-free survival of 5 months. Our study improved knowledge of clinical characteristics and molecular features of RET-rearranged lung cancers in China. It might be helpful to guide clinicians for more effective personalized diagnostic and therapeutic approaches.

Lung cancer in never smokers-the East Asian experience

Approximately one third of all lung cancer patients in East Asia are never-smokers. Furthermore, the proportion of lung cancer in never smokers (LCINS) has been increasing over time. Never-smokers are more often diagnosed with adenocarcinoma in East Asia, a subtype largely defined by oncogenic drivers. In this subgroup of patients, as high as 90% of patients have been found to harbor well-known oncogenic mutations and can be successfully managed with targeted therapies inhibiting specific oncogenic mutant kinases. EGFR tyrosine kinase inhibitor (EGFR-TKI) treatment has been the most important targeted therapy in lung adenocarcinoma from East Asian never-smokers as approximately 70% of these patients have the opportunity to receive EGFR-TKI treatment. Lung squamous cell carcinoma (SQCC) and small cell lung cancer (SCLC) are two common histologic types of smoking-related non-small cell lung cancer (NSCLC). The proportion of never-smokers with SQCC and SCLC in East Asian patients seems to be higher than that in Caucasian patients. Recent studies also suggest that lung SQCC and SCLC in never-smokers may be distinct subtypes. Therefore, better understanding of the biologic characteristics of these subtypes of patients may provide new insights for the treatment. In this review, we will provide an overview of East Asian experience in the treatment of advanced, never-smoking lung cancer, focusing on etiologic factors in the development of LCINS, targeted therapy for never-smokers with adenocarcinoma, distinct characteristics of never-smokers with lung SQCC and SCLC, and the role of immunotherapy in never-smokers with NSCLC.

Prognostic value of PD-L1 expression in combination with CD8+ TILs density in patients with surgically resected non-small cell lung cancer

To investigate the prognostic value of PD-L1 expression combined with CD8+ TILs density in patients with resected NSCLC and correlations with clinicopathological features. We retrospectively enrolled 178 patients with resected NSCLC from 2011 to 2015. All surgical primary and 58 matched metastatic lymph node specimens were tested for PD-L1, CD8+ TILs, and oncogenic alterations. PD-L1+ was detected in 71 (39.9%) and CD8high TILs in 74 (41.6%) cases. Smoking, SqCC, and EGFR- were associated with both PD-L1+ and CD8high TILs. Patients with CD8high TILs had longer OS (P = 0.012). PD-L1- was significantly associated with longer OS in patients with oncogenic alterations (P = 0.047). By multivariate analysis, CD8high TILs (HR = 0.411; 95% CI, 0.177-0.954; P = 0.038), rather than PD-L1, was the independent predictive factor for OS. The longest and shortest OS were achieved in patients with PD-L1+ /CD8high and PD-L1+ /CD8low , respectively (P = 0.025). Inconsistent PD-L1 expression levels were observed in 23 of 58 (39.7%) patients with primary and matched metastatic lymph node specimens. Of them, CD8high TILs was significantly associated with longer OS in patients with metastatic lymph nodes and/or consistent PD-L1 expression (P = 0.017 and 0.049, respectively). The combination of PD-L1 and CD8+ TILs density, instead of PD-L1 alone, suggested impressive prognostic values in NSCLC patients. Less than half of patients with resected NSCLC experienced inconsistent PD-L1 expression between primary and metastatic lesions. The level of PD-L1 expression in advanced NSCLC needs to be evaluated more comprehensively.

Distinct clinicopathologic features, genomic characteristics and survival of central and peripheral pulmonary large cell neuroendocrine carcinoma: From different origin cells?

BACKGROUND

Pulmonary large cell neuroendocrine carcinoma (LCNEC) represents a rare entity in lung cancer with dismal prognosis. In the present study, we investigated whether there are significant differences between central and peripheral tumors of LCNEC, in terms of clinicopathologic features, genomic profiles, and survival.

METHODS AND MATERIALS

A total of 126 cases of LCNEC were included. The tumors with invasion of the segmental and/or lobar bronchus were classified as central LCNEC and those without as peripheral LCNEC. EGFR/BRAF/Kras mutations and ALK/ROS1 translocations were detected. Overall survival (OS) was evaluated by the Kaplan-Meier plots.

RESULTS

The majority of LCNEC proved to be of the peripheral type (64.3%, 81/126). Central tumors were associated with smoking habit (p = 0.047), higher TNM-stage (p = 0.014) and larger tumor size (p < 0.001). Expression of neuroendocrine markers (CD56, CGA, and SYN) was not significantly different by tumor location but central tumors had higher serum levels of NSE (p = 0.004). Peripheral tumors had a higher incidence of EGFR mutations (18.8% vs. 0%, p = 0.023). ROS1 translocation was detected in 1 patient with peripheral LCNEC. RB1 protein was more frequently expressed in peripheral tumor than central tumor. The median OS was 3.71 years in the entire cohort. Peripheral tumors had better survival compared with central tumors (median OS: 4.04 vs. 1.51 years, p < 0.001). Multivariate analyses demonstrated tumor location (hazard ratio [HR], 6.07, 95% confidence interval [CI], 1.57-23.44, p = 0.009), resection status (HR, 6.58, 95% CI, 1.92-22.51, p = 0.003) and EGFR mutational status (HR, 0.18, 95% CI, 0.04-0.75, p = 0.018) were independent prognostic factors for OS.

CONCLUSION

Primary tumor location of LCNEC, divided into central and peripheral type, has distinct clinicopathologic features, genomic characteristics and survival. These differences are likely due to differences in the origin cells and pathogenesis of these tumors.

Targeting RET-driven cancers: lessons from evolving preclinical and clinical landscapes

The gene encoding the receptor-tyrosine kinase RET was first discovered more than three decades ago, and activating RET rearrangements and mutations have since been identified as actionable drivers of oncogenesis. Several multikinase inhibitors with activity against RET have been explored in the clinic, and confirmed responses to targeted therapy with these agents have been observed in patients with RET-rearranged lung cancers or RET-mutant thyroid cancers. Nevertheless, response rates to RET-directed therapy are modest compared with those achieved using targeted therapies matched to other oncogenic drivers of solid tumours, such as sensitizing EGFR or BRAF^V600E mutations, or ALK or ROS1 rearrangements. To date, no RET-directed targeted therapeutic has received regulatory approval for the treatment of molecularly defined populations of patients with RET-mutant or RET-rearranged solid tumours. In this Review, we discuss how emerging data have informed the debate over whether the limited success of multikinase inhibitors with activity against RET can be attributed to the tractability of RET as a drug target or to the lack, until 2017, of highly specific inhibitors of this oncoprotein in the clinic. We emphasize that novel approaches to targeting RET-dependent tumours are necessary to improve the clinical efficacy of single-agent multikinase inhibition and, thus, hasten approvals of RET-directed targeted therapies.

Clinical and Translational Implications of RET Rearrangements in Non-Small Cell Lung Cancer

Since the discovery in 2012 of rearranged during transfection proto-oncogene gene (RET) rearrangements in NSCLC, at least 12 different fusion variants have been identified, with kinesin family member 5B gene (KIF5B)-RET being the most frequent and the best characterized. Unlike ALK receptor tyrosine kinase gene (ALK) and ROS1 rearrangements, RET fusion genes cannot be adequately detected by immunohistochemistry (IHC), although fluorescence in situ hybridization and reverse transcriptase polymerase chain reaction are fully complementary diagnostic tools. In large retrospective studies, RET rearrangements correlate with adenocarcinoma histologic subtype, never-smoking status, younger age, more advanced disease stage, potentially higher chemosensitivity (in particular, to pemetrexed-based regimens), and coexistence of other genomic alterations. To date, several preclinical models, clinical trials, and retrospective studies have investigated multitarget inhibitors with anti-rearranged during transfection proto-oncogene (RET) activity in patients with RET-rearranged lung cancer. In the clinical setting, the benefit in terms of response (16%-47%) and progression-free survival (2-7 months) is clearly not comparable to that seen with other targeted agents in oncogene-addicted NSCLC. Furthermore, multikinase agents showed high rates of severe toxicities, leading to frequent dose reduction and drug discontinuation. To date, no definitive conclusions about a potentially different impact of anti-RET therapies according to RET fusion variants have been drawn on account of discordant data coming mostly from small subgroup analyses. Importantly, the absence of a striking clinical benefit in RET oncogene-addicted NSCLC underscores the clear need for development of more selective and potent RET inhibitors and for better characterization of concomitant genomic alterations and mechanisms of resistance to RET inhibition in patients with lung cancer.

KIF5B/RET Rearrangement in a Carcinoma of the Thyroid Gland: A Case Report of a Fatal Disease

BACKGROUND

The diffuse sclerosing variant of papillary thyroid cancer (DSV-PTC) is a rare variant of papillary thyroid cancer (PTC) with different clinicopathological features compared with conventional PTC.

CASE

An advanced DSV-PTC was diagnosed in a 39-year-old man. The radioiodine posttherapeutic whole-body-scan showed only an uptake in the central neck, whereas the computerized tomography showed multiple latero-cervical and mediastinum lymph node metastases, a single and spiculated lung lesion and multiple bilateral cerebellum metastases. The patient died after 6 months from the initial diagnosis. The histological revision of the thyroid tumor confirmed the diagnosis of DSV-PTC, and its molecular analysis revealed a KIF5B/RET rearrangement that, until now, was described only in a minority of lung adenocarcinoma. Other 18 cases of DSV-PTC were then studied for the presence of KIF5B/RET rearrangement, but all of them were negative.

CONCLUSIONS

This was a case of DSV-PTC positive for KIF5B/RET rearrangement, but considering that this alteration has been described only in lung adenocarcinoma and that the clinical course was more typical of lung carcinoma, we cannot completely rule out the possibility that this was a metastatic lesion from a lung tumor mimicking a DSV-PTC. As an alternative, we can also hypothesize that this was a case of fusion of two tumoral tissues deriving from a DSV-PTC and a metastasis of a KIF5B/RET positive lung adenocarcinoma. The question of whether the molecular findings, particularly when specifically reported only in some subtypes of human tumors, can overcome the morphological diagnosis is a matter of discussion.

Targeting RET in Patients With RET-Rearranged Lung Cancers: Results From the Global, Multicenter RET Registry

Purpose In addition to prospective trials for non-small-cell lung cancers (NSCLCs) that are driven by less common genomic alterations, registries provide complementary information on patient response to targeted therapies. Here, we present the results of an international registry of patients with RET-rearranged NSCLCs, providing the largest data set, to our knowledge, on outcomes of RET-directed therapy thus far. Methods A global, multicenter network of thoracic oncologists identified patients with pathologically confirmed NSCLC that harbored a RET rearrangement. Molecular profiling was performed locally by reverse transcriptase polymerase chain reaction, fluorescence in situ hybridization, or next-generation sequencing. Anonymized data-clinical, pathologic, and molecular features-were collected centrally and analyzed by an independent statistician. Best response to RET tyrosine kinase inhibition administered outside of a clinical trial was determined by RECIST v1.1. Results By April 2016, 165 patients with RET-rearranged NSCLC from 29 centers across Europe, Asia, and the United States were accrued. Median age was 61 years (range, 29 to 89 years). The majority of patients were never smokers (63%) with lung adenocarcinomas (98%) and advanced disease (91%). The most frequent rearrangement was KIF5B-RET (72%). Of those patients, 53 received one or more RET tyrosine kinase inhibitors in sequence: cabozantinib (21 patients), vandetanib (11 patients), sunitinib (10 patients), sorafenib (two patients), alectinib (two patients), lenvatinib (two patients), nintedanib (two patients), ponatinib (two patients), and regorafenib (one patient). The rate of any complete or partial response to cabozantinib, vandetanib, and sunitinib was 37%, 18%, and 22%, respectively. Further responses were observed with lenvantinib and nintedanib. Median progression-free survival was 2.3 months (95% CI, 1.6 to 5.0 months), and median overall survival was 6.8 months (95% CI, 3.9 to 14.3 months). Conclusion Available multikinase inhibitors had limited activity in patients with RET-rearranged NSCLC in this retrospective study. Further investigation of the biology of RET-rearranged lung cancers and identification of new targeted therapeutics will be required to improve outcomes for these patients.

High Discrepancy of Driver Mutations in Patients with NSCLC and Synchronous Multiple Lung Ground-Glass Nodules

BACKGROUND

The aim of this study was to investigate the discordance rates of eight known driver mutations among multiple matched intrapulmonary ground-glass nodules (GGNs) in non-small-cell lung cancer (NSCLC) patients.

METHODS

Tumors from 35 patients with multiple lesions resected, including confirmed NSCLC and at least one GGN, were analyzed for mutations in EGFR, KRAS, HER2, BRAF, and PIK3CA together with fusions in ALK, ROS1, and RET.

RESULTS

From 35 patients, a total of 72 lesions (60 were GGNs) were analyzed. These included nine adenocarcinoma in situ, nine minimal invasive adenocarcinoma, and 54 invasive adenocarcinoma. Among them, 33 tumor lesions (45.8 %) were found harboring EGFR mutations: 13 tumors with exon 19 deletion, 18 with L858R on exon 21, and two with both exon 19 del and L858R mutation. There were 5 tumors (6.9 %) harboring EML4-ALK fusion, four HER2 mutations (5.6%), three KRAS mutations (4.2%), one ROS1 fusion and one BRAF mutation. When we used the matched tumors to determine the intertumor discrepancy, only six out of 30 patients harbored identical mutations. The discordance rate of driver mutations was 80% (24 of 30) in those patients harboring at least one of the detected driver mutations. The median disease-free survival was 41.2 months (95% confidence interval: 35.8-52.6 months) and the median overall survival was "still not reached" in this cohort.

CONCLUSIONS

We found a high discrepancy of driver mutations among NSCLC patients with GGNs and a favorable prognosis after multiple lesions resection, which support surgical resection in this situation as a reasonable approach.

Intratumoral Heterogeneity of ALK-Rearranged and ALK/EGFR Coaltered Lung Adenocarcinoma

PURPOSE

Genetic intratumoral heterogeneity has a profound influence on the selection of clinical treatment strategies and on addressing resistance to targeted therapy. The purpose of this study was to explore the potential effect of intratumoral heterogeneity on both genetic and pathologic characteristics of ALK-rearranged lung adenocarcinoma (LADC).

METHODS

We tested ALK fusions and EGFR mutations in 629 patients with LADC by using laser-capture microdissection to capture spatially separated tumor cell subpopulations in various adenocarcinoma subtypes and to test for ALK fusions and EGFR mutations in ALK-rearranged, EGFR-mutated, and ALK/EGFR coaltered LADCs to compare the oncogenic driver status between different tumor cell subpopulations in the same primary tumor.

RESULTS

Among the 629 patients, 30 (4.8%) had ALK fusions, 364 (57.9%) had EGFR mutations, and two had ALK fusions that coexisted with EGFR mutations. Intratumoral heterogeneity of ALK fusions were identified in nine patients by reverse-transcriptase polymerase chain reaction. In the two patients with an ALK/EGFR coaltered status, genetic intratumoral heterogeneity was observed both between different growth patterns and within the same growth pattern. The relative abundance of ALK and EGFR alterations was different in the same captured area. ALK fusions were positively associated with a micropapillary pattern (P = .002) and were negatively associated with a lepidic pattern (P = .008) in an expanded statistical analysis of 900 individual adenocarcinoma components, although they appeared to be more common in acinar-predominant LADCs in the analysis of 629 patients.

CONCLUSION

Intratumoral genetic heterogeneity was demonstrated to coexist with histologic heterogeneity in both single-driver and ALK/EGFR coaltered LADCs. Altered oncogenic drivers in spatially separated subclones of the same tumor may be different.

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.

The RET fusion gene and its correlation with demographic and clinicopathological features of non-small cell lung cancer: a meta-analysis

PURPOSE

The RET fusion gene is a novel oncogene observed in a subset of NSCLC in recent years. Nevertheless, the results of epidemiological studies concerning the gene remain unclear. Thus, a meta-analysis was conducted to evaluate the correlation of RET fusion gene with demographic and clinicopathological features of NSCLC.

METHODS

PubMed, Embase, and Web of Science databases were searched to identify eligible studies. The association of RET fusion gene occurrence with gender, age, smoking status, histology type and tumor stage were analyzed in meta-analysis. Subgroup analysis according to patients' location (Asian and non-Asian) was also conducted. Odds ratio (OR) and 95% confidence interval (95% CI) were calculated to assess the correlation.

RESULTS

Nine studies with a total of 6,899 NSCLC patients met the inclusion criteria. A total of 84 patients with RET fusion gene were detected. The RET fusion gene was identified at significantly higher frequencies in female (OR = 0.55, 95%CI = 0.35-0.85) than male patients and in young (<60) patients (OR = 0.43, 95%CI = 0.19-0.99) than old patients (≤60), particularly in patients from Asian. A significant higher frequency was also identified in non-smokers (OR = 0.28, 95% CI = 0.16-0.49), and in patients with lung adenocarcinomas (OR = 3.59, 95%CI = 1.50-8.56). Additionally, no association between RET fusion gene and the TNM stage of tumor was observed.

CONCLUSION

RET fusion gene occurred predominantly in Asian females with younger age, in non-smokers, and in lung adenocarcinomas patients. This subset of NSCLC patients might be good candidates for personalized diagnostic and therapeutic approaches.

Comprehensive analysis of RET and ROS1 rearrangement in lung adenocarcinoma

The success of crizotinib in ALK-positive patients has elicited efforts to find new oncogenic fusions in lung cancer. These efforts have led to the discovery of novel oncogenic fusion genes such as ROS1 and RET. However, the molecular and clinicopathologic characteristics associated with RET or ROS1 fusion, compared with ALK fusion-positive lung cancer, remain unclear. We accordingly analyzed the clinicopathologic characteristics of RET- and ROS1-fusion-positive lung adenocarcinomas. We further performed immunohistochemistry and fluorescence in situ hybridization analysis (FISH) in 15 cases of RET and 9 cases of ROS1 fusion tumors by identified NanoString's nCounter screening. RET fusion-positive patients were younger in age, never-smokers, and in early T stage; ROS1 fusion-positive patients had a higher number of never-smokers compared with patients with quintuple-negative (EGFR-/KRAS-/ALK-/ROS1-/RET-) lung adenocarcinoma. Histologically, RET and ROS1 fusion tumors share the solid signet-ring cell and mucinous cribriform pattern, as previously mentioned in the histology of ALK fusion tumors. Therefore, it can be presumed that fusion gene-associated lung adenocarcinomas share similar histologic features. In immunohistochemistry, the majority of 15 RET and 9 ROS1 fusion-positive cases showed positivity of more than moderate intensity and cytoplasmic staining for RET and ROS1 proteins, respectively. In FISH, the majority of RET and ROS1 rearrangement showed two signal patterns such as one fusion signal and two separated green and orange signals (1F1G1O) and an isolated 3' green signal pattern (1F1G). Our study has provided not only characteristics of fusion gene-associated histologic features but also a proposal for a future screening strategy that will enable clinicians to select cases needed to be checked for ROS1 and RET rearrangements based on clinicohistologic features.

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.

A retrospective analysis of RET translocation, gene copy number gain and expression in NSCLC patients treated with vandetanib in four randomized Phase III studies

Background

To determine the prevalence of RET rearrangement genes, RET copy number gains and expression in tumor samples from four Phase III non-small-cell lung cancer (NSCLC) trials of vandetanib, a selective inhibitor of VEGFR, RET and EGFR signaling, and to determine any association with outcome to vandetanib treatment.

Methods

Archival tumor samples from the ZODIAC (NCT00312377, vandetanib ± docetaxel), ZEAL (NCT00418886, vandetanib ± pemetrexed), ZEPHYR (NCT00404924, vandetanib vs placebo) and ZEST (NCT00364351, vandetanib vs erlotinib) studies were evaluated by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) in 944 and 1102 patients.

Results

The prevalence of RET rearrangements by FISH was 0.7% (95% CI 0.3–1.5%) among patients with a known result. Seven tumor samples were positive for RET rearrangements (vandetanib, n = 3; comparator, n = 4). 2.8% (n = 26) of samples had RET amplification (innumerable RET clusters, or ≥7 copies in > 10% of tumor cells), 8.1% (n = 76) had low RET gene copy number gain (4–6 copies in ≥40% of tumor cells) and 8.3% (n = 92) were RET expression positive (signal intensity ++ or +++ in >10% of tumor cells). Of RET-rearrangement-positive patients, none had an objective response in the vandetanib arm and one patient responded in the comparator arm. Radiologic evidence of tumor shrinkage was observed in two patients treated with vandetanib and one treated with comparator drug. The objective response rate was similar in the vandetanib and comparator arms for patients positive for RET copy number gains or RET protein expression.

Conclusions

We have identified prevalence for three RET biomarkers in a population predominated by non-Asians and smokers. RET rearrangement prevalence was lower than previously reported. We found no evidence of a differential benefit for efficacy by IHC and RET gene copy number gains. The low prevalence of RET rearrangements (0.7%) prevents firm conclusions regarding association of vandetanib treatment with efficacy in the RET rearrangement NSCLC subpopulation.

Trial registration

Randomized Phase III clinical trials (NCT00312377, ZODIAC; NCT00418886, ZEAL; NCT00364351, ZEST; NCT00404924, ZEPHYR).

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1146-8) contains supplementary material, which is available to authorized users.

Molecularly targeted therapies in non-small-cell lung cancer annual update 2014

There have been significant advances in the understanding of the biology and treatment of non-small-cell lung cancer (NSCLC) during the past few years. A number of molecularly targeted agents are in the clinic or in development for patients with advanced NSCLC. We are beginning to understand the mechanisms of acquired resistance after exposure to tyrosine kinase inhibitors in patients with oncogene addicted NSCLC. The advent of next-generation sequencing has enabled to study comprehensively genomic alterations in lung cancer. Finally, early results from immune checkpoint inhibitors are very encouraging. This review summarizes recent advances in the area of cancer genomics, targeted therapies, and immunotherapy.

Republished: lung cancer in never-smokers. Does smoking history matter in the era of molecular diagnostics and targeted therapy?

Lung cancer in never-smokers was recognised as a distinct clinical entity around the mid-2000s because these patients tended to be Asian women and diagnosed at a younger age with a preponderance of adenocarcinoma and better survival outcome despite a more advanced stage of presentation. It was soon discovered that lung cancer in never-smokers had a higher prevalence of activating EGFR mutations and we tend to classify lung cancer by smoking status for screening purpose. With the discoveries of many actionable driver mutations such as activating EGFR mutations and ALK rearrangement in adenocarcinoma of the lung we have switched to classifying non-small cell lung cancer into different individual molecular subgroups based on the presence of a dominant driver mutation. Although many actionable driver mutations are found in never-smokers with adenocarcinoma, this review will summarise that a substantial proportion of patients with these actionable driver mutations had a previous smoking history. Alternatively among the driver mutations that are associated with smoking history, a fair amount of these patients were never-smokers. Thus smoking status should not be used as a screen strategy for identifying driver mutations in clinical practice. Finally smoking history may have predictive and/or prognostic significance within individual molecular subgroups and identifying the difference according to smoking history may help optimise future targeted therapy.

KIF5B-RET fusion kinase promotes cell growth by multilevel activation of STAT3 in lung cancer

Background

Lung cancer in nonsmokers tends to be driven by a single somatic mutation or a gene fusion. KIF5B-RET fusion is an oncogene identified in non-small cell lung cancers. In this study, we verified the oncogenic activity of KIF5B-RET fusion and investigated how KIF5B-RET activates the specific signaling pathways for cellular transformation. We aimed to provide a basis for the further development of the therapy for KIF5B-RET positive lung cancer patients.

Methods

RT-PCR was used to screen for KIF5B-RET fusions in Chinese lung cancer patients. To verify the oncogenic activity of KIF5B-RET kinase in lung cancer cells, we manipulated its expression genetically followed by colony formation and tumor formation assays. The mechanism by which KIF5B-RET kinase induces proliferation was investigated by western blot, coimmunoprecipitation, and administration of RET, MAPK and STAT3 inhibitors.

Results

Our study identified a KIF5B-RET fusion in Chinese NSCLC patients and demonstrated that KIF5B-RET transfected cells showed a significantly increased proliferation rate and colony-forming ability. Furthermore, we found that KIF5B-RET fusion kinase induced multilevel activation of STAT3 at both Tyr⁷⁰⁵ and Ser⁷²⁷, and KIF5B-RET-STAT3 signaling related inhibitors repressed the proliferation and tumorigenicity of lung cancer cells significantly.

Conclusions

Our data suggest that KIF5B-RET promotes the cell growth and tumorigenicity of non-small cell lung cancers through multilevel activation of STAT3 signaling, providing possible strategies for the treatment of KIF5B-RET positive lung cancers.

Detecting ALK, ROS1 and RET Fusion Genes in Cell Block Samples

Whether Cell block (CB) samples are applicable to detect anaplastic lymphoma kinase (ALK), c-ros oncogene 1 (ROS1) and ret proto-oncogene (RET) fusion genes in lung adenocarcinoma is still unknown. In this study, 108 cytological samples that contained lung adenocarcinoma cells were collected, and made into CB. The CB samples all contained at least 30% lung adenocarcinoma cells. In these patients, 48 harbored EGFR mutation. Among the 50 EGFR wild type patients who detected fusion genes, 14 carried EML4-ALK fusion (28%), 2 had TPM3-ROS1 fusion (4%), and 3 harbored KIF5B-RET fusion (6%). No double fusions were found in one sample. Patients with fusion genes were younger than those without fusion genes (p = 0.032), but no significant difference was found in sex and smoking status (p > 0.05). In the thirty-five patients who received first-line chemotherapy, patients with fusion gene positive had disease control rate (DCR) (72.7% VS 50%, p > 0.05) and objective response rate (ORR) (9.1% VS 4.2%, p > 0.05) compared with those having fusion gene negative. The median progression free survival (mPFS) were 4.0 and 2.7 months in patients harbored fusion mutations and wild type, respectively (p > 0.05). We conclude that CB samples could be used to detect ALK, ROS1 and RET fusions in NSCLC. The frequency distribution of three fusion genes is higher in lung adenocarcinoma with wild-type EGFR, compared with unselected NSCLC patient population. Patients with fusion genes positive are younger than those with fusion gene negative, but they had no significantly different PFS in first-line chemotherapy.

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.

RET fusion gene: translation to personalized lung cancer therapy

Development of lung adenocarcinoma (LADC), the most frequent histological type of lung cancer, depends in many cases on the activation of "driver" oncogenes such as KRAS, epidermal growth factor receptor (EGFR), and anaplastic lymphoma kinase (ALK). Inhibitors that target the EGFR and ALK tyrosine kinases show therapeutic effects against LADCs containing EGFR gene mutations and ALK gene fusions, respectively. Recently, we and others identified the RET fusion gene as a new targetable driver gene in LADC. The RET fusions occur in 1-2% of LADCs. Existing US Food and Drug Administration-approved inhibitors of RET tyrosine kinase show promising therapeutic effects both in vitro and in vivo, as well as in a few patients. Clinical trials are underway to investigate the therapeutic effects of RET tyrosine kinase inhibitors, such as vandetanib (ZD6474) and cabozantinib (XL184), in patients with RET fusion-positive non-small-cell lung cancer.