Comparison of ALK detection by FISH, IHC and NGS to predict benefit from crizotinib in advanced non-small-cell lung cancer

IHC versus FISH versus NGS to detect ALK gene rearrangement in NSCLC: all questions answered?

AIMS

Anaplastic lymphoma kinase (ALK) rearranged non-small cell lung carcinoma (NSCLC) is a distinct molecular subtype and rapid approval of ALK tyrosine kinase inhibitors (TKIs) has necessitated rapid and sensitive diagnostic modalities for the detection of this alteration. Gene rearrangements can be identified using many techniques including fluorescence in situ hybridisation (FISH), reverse transcriptase-PCR, next-generation sequencing (NGS) and immunohistochemistry (IHC) for fusion oncoprotein expression. We aimed to determine the concordance between IHC, FISH and NGS for ALK biomarker detection, and determine differences in sensitivity, and survival outcomes.

METHODS

We analysed the concordance between IHC using D5F3 monoclonal antibody, FISH (break-apart) and NGS using a custom panel containing 71 different ALK variants.

RESULTS

Among 71 cases included in this study, FISH was evaluable in 58 cases. The concordance of ALK IHC with FISH was 75.9% and that with NGS was 84.5%. The sensitivities of FISH and NGS were 75.6% and 87.5%, respectively. The median progression-free survival of ALK IHC-positive and FISH-negative group was 5.5 months and that of both positive was 9.97 months.

CONCLUSION

Although NGS offers a better throughput and visualisation, IHC still remains the quintessential screening tool in upfront diagnosis of ALK rearranged NSCLC.

Concomitant mutation status of ALK-rearranged non-small cell lung cancers and its prognostic impact on patients treated with crizotinib

Background

In non-small cell lung cancer (NSCLC), anaplastic lymphoma kinase (ALK) rearrangement characterizes a subgroup of patients who show sensitivity to ALK tyrosine kinase inhibitors (TKIs). However, the prognoses of these patients are heterogeneous. A better understanding of the genomic alterations occurring in these tumors could explain the prognostic heterogeneity observed in these patients.

Methods

We retrospectively analyzed 96 patients with NSCLC with ALK detected by immunohistochemical staining (VENTANA anti-ALK(D5F3) Rabbit Monoclonal Primary Antibody). Cancer tissues were subjected to next-generation sequencing using a panel of 520 cancer-related genes. The genomic landscape, distribution of ALK fusion variants, and clinicopathological characteristics of the patients were evaluated. The correlations of genomic alterations with clinical outcomes were also assessed.

Results

Among the 96 patients with immunohistochemically identified ALK fusions, 80 (83%) were confirmed by next-generation sequencing. TP53 mutation was the most commonly co-occurring mutation with ALK rearrangement. Concomitant driver mutations [2 Kirsten rat sarcoma viral oncogene homolog (KRAS) G12, 1 epidermal growth factor receptor (EGFR) 19del, and 1 MET exon 14 skipping] were also observed in 4 adenocarcinomas. Echinoderm microtubule associated protein-like 4 (EML4)-ALK fusions were identified in 95% of ALK-rearranged patients, with 16.2% of them also harboring additional non-EML4-ALK fusions. Nineteen non-EML4 translocation partners were also discovered, including 10 novel ones. Survival analyses revealed that patients concurrently harboring PIK3R2 alterations showed a trend toward shorter progression-free survival (6 vs. 13 months, P=0.064) and significantly shorter overall survival (11 vs. 32 months, P=0.004) than did PIK3R2-wild-type patients. Patients with concomitant alterations in PI3K the signaling pathway also had a shorter median overall survival than those without such alterations (23 vs. 32 months, P=0.014), whereas progression-free survival did not differ significantly.

Conclusions

The spectrum of ALK-fusion variants and the landscape of concomitant genomic alterations were delineated in 96 NSCLC patients. Our study also demonstrated the prognostic value of concomitant alterations in crizotinib-treated patients, which could facilitate improved stratification of ALK-rearranged NSCLC patients in the selection of candidates who could optimally benefit from therapy.

An intergenic region ALK fusion identified by DNA sequencing and validated by IHC in an early-stage lung adenocarcinoma

Anaplastic Lymphoma Kinase (ALK) fusion is an important driver mutation and therapeutic target. At present, more than 20 fusion partners for ALK in NSCLC have been reported. However, ALK intergenic-breakpoint fusions confound fusion detection and target treatment. Here, we reported a 53-year-old early-stage lung adenocarcinoma patient with an MIR548AD-ALK intergenic fusion and was verified by immunohistochemical staining (IHC). In early-stage NSCLC, compared with other clinically relevant driver mutations, ALK fusions were associated with a trend toward poor disease outcomes. Our Next-generation sequencing (NGS) and IHC results may indicate the prognosis of the patient and provide an alternative treatment option for postoperative recurrence.

Distribution and therapeutic outcomes of intergenic sequence-ALK fusion and coexisting ALK fusions in lung adenocarcinoma patients

INTRODUCTION

Patients with ALK rearranged non-small-cell lung cancer (NSCLC) show survival benefits from tyrosine-kinase inhibitor (TKI). Widely application of DNA sequencing revealed various rearrangement pattern in addition to single EML4-ALK fusion. Here, we retrospectively analyzed the distribution and coexistence of ALK rearrangement and therapeutic outcome of patients with ALK rearranged NSCLC.

METHOD

ALK positive NSCLC patients were screened at West China Hospital. NGS was performed on pre-treatment samples. Clinical characteristics and therapeutic outcomes were collected to retrospectively analyzed.

RESULTS

Among the 89 patients with 22 ALK rearrangements, fusions of intergenic sequences with ALK were found in 15 (16.85 %). Non-EML4-ALK fusions were present in 18 patients (20.22 %). Coexistence of rearrangements were present in 16 patients (17.98 %). Intergenic sequence-ALK and non-EML4-ALK fusions occurred at higher rates in patients with at least two fusions (62.5 % versus 6.85 % for intergenic sequence-ALK, 62.5 % versus 10.96 % for non-EML4-ALK). There were 40 ALK-rearranged NSCLC patients receiving the first-line crizotinib. The median progression-free survival (PFS) was 9.7 months when excluding three lost patients. In the seven patients who had at least two fusions, the median PFS was 11.9 months, compared with 9.0 months among those with single (p = 0.336). No significant difference in median PFS was found between patients with and without intergenic-ALK fusion (12.0 months versus 9.6 months, p = 0.989). The median PFS was 9.0 months in patients harboring a single EML4-ALK fusion versus 13.0 months in those with other ALK alterations (P = 0.890). The PFS of patients with single intergenic sequence-ALK fusion reached to 2.9 months, 27 months, and 28.9 months respectively.

CONCLUSION

Our study reports the distribution of intergenic sequence-ALK and coexisting fusions in ALK-rearranged NSCLC. Intergenic sequence-ALK and non-EML4-ALK are prone to coexist with other fusions. Neither intergenic sequence-ALK nor coexistence of fusions had a significant effect on the therapeutic benefit of treatment with crizotinib.

Clinicopathologic features of kinase fusion-related thyroid carcinomas: an integrative analysis with molecular characterization

The discovery of actionable kinase gene rearrangements has revolutionized the therapeutic landscape of thyroid carcinomas. Unsolved challenges include histopathologic recognition of targetable cases, correlation between genotypes and tumor behavior, and evolving resistance mechanisms against kinase inhibitors (KI). We present 62 kinase fusion-positive thyroid carcinomas (KFTC), including 57 papillary thyroid carcinomas (PTC), two poorly differentiated thyroid carcinomas (PDTC), two undifferentiated thyroid carcinomas (ATC), and one primary secretory carcinoma (SC), in 57 adults and 5 adolescents. Clinical records, post-operative histology, and molecular profiles were reviewed. Histologically, all KFTC showed multinodular growth with prominent intratumoral fibrosis. Lymphovascular invasion (95%), extrathyroidal extension, gross and microscopic (63%), and cervical lymph node metastasis (79%) were common. Several kinase fusions were identified: STRN-ALK, EML4-ALK, AGK-BRAF, CUL1-BRAF, MKRN1-BRAF, SND1-BRAF, TTYH3-BRAF, EML4-MET, TFG-MET, IRF2BP2-NTRK1, PPL-NTRK1, SQSTM1-NTRK1, TPR-NTRK1, TPM3-NTRK1, EML4-NTRK3, ETV6-NTRK3, RBPMS-NTRK3, SQSTM1-NTRK3, CCDC6-RET, ERC1-RET, NCOA4-RET, RASAL2-RET, TRIM24-RET, TRIM27-RET, and CCDC30-ROS1. Individual cases also showed copy number variants of EGFR and nucleotide variants and indels in pTERT, TP53, PIK3R1, AKT2, TSC2, FBXW7, JAK2, MEN1, VHL, IDH1, PTCH1, GNA11, GNAQ, SMARCA4, and CDH1. In addition to thyroidectomy and radioactive iodine, ten patients received multi-kinase and/or selective kinase inhibitor therapy, with 6 durable, objective responses and four with progressive disease. Among 47 cases with >6 months of follow-up (median [range]: 41 [6-480] months), persistent/recurrent disease, distant metastasis and thyroid cancer-related death occurred in 57%, 38% and 6%, respectively. In summary, KFTC encompass a spectrum of molecularly diverse tumors with overlapping clinicopathologic features and a tendency for clinical aggressiveness. Characteristic histology with multinodular growth and prominent fibrosis, particularly when there is extensive lymphovascular spread, should trigger molecular testing for gene rearrangements, either in a step-wise manner by prevalence or using a combined panel. Further, our findings provide information on molecular therapy in radioiodine-refractory thyroid carcinomas.

Combination of crizotinib and chemotherapy in patients with relapsed or refractory anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL)

Our aim was to explore the role of crizotinib, targeted anaplastic lymphoma kinase (ALK), on r/r systemic anaplastic large cell lymphoma (sALCL). The treated group prospectively screened 20 patients. After taking crizotinib in the first week, 16 patients who were tolerant and sensitive received the combination of crizotinib with chemotherapy. The control group included 27 patients receiving chemotherapy in the same hospital during the same period. The objective remission rates of the treated and control group were 81.3% and 74.1% (p = .869), respectively. The progression-free survival rates at two years in treated and control group were 68.7% and 45.0% (HR = 0.42, 95% CI 0.17-0.99, p < .05), respectively. The overall survival rates at two years in the treated and control group were 86.1% and 78.9% (p = .385, HR = 0.51, 95% CI 0.11-2.30), respectively. The main adverse events included elevated transaminase, diarrhea, and vision abnormalities. Thus, the combination of crizotinib with chemotherapy might be effective in ALK-positive and crizotinib sensitive r/r sALCL patients.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

KEY POINTS

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

WHAT THIS STUDY ADDS

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

Comparison of Next-Generation Sequencing and Ventana Immunohistochemistry in Detecting ALK Rearrangements and Predicting the Efficacy of First-Line Crizotinib in Patients with Advanced Non-Small Cell Lung Cancer

Introduction

Reliable diagnostic approaches to detect ALK rearrangement are critical for selecting patients eligible for crizotinib therapy. This study aimed to compare next-generation sequencing (NGS) and Ventana immunohistochemistry (IHC) in evaluating ALK rearrangements and evaluate their impact on first-line crizotinib efficacy.

Patients and Methods

A total of 472 NSCLC patients were identified as ALK-positive by NGS and/or IHC between March 2014 and February 2020. The concordance of ALK detection, overall response rate (ORR), and progression-free survival (PFS) were analyzed for 319 patients who received front-line crizotinib.

Results

First-line crizotinib (n=319) significantly prolonged PFS in comparison with chemotherapy (n=46; 12.0 vs 6.8 months; p<0.0001). Of the 76 crizotinib-treated patients whose ALK status was assessed by both NGS and IHC, 78.9% of the patients had concordant ALK status (NGS-positive/IHC-positive), 18.4% patients were NGS-positive but IHC-negative, and 2 patients were IHC-positive but NGS-negative. Different detection assays confer no statistical difference in ORR and PFS with first-line crizotinib. The ORR in NGS only, IHC only, and both NGS and IHC was 84.3%, 90.1%, and 88.1%, respectively, while PFS was 11.4, 13.0, and 11.0 months, respectively. The ORR in NGS-positive/IHC-positive and NGS-positive/IHC-negative patients was 85.4% and 92.8%, respectively. Compared to NGS-positive/IHC-positive patients, those with NGS-positive/IHC-negative results had a trend of shorter PFS but statistical significance was not reached (mPFS, 5.9 months vs 11.5 months, p=0.43).

Conclusion

Our results demonstrate that ALK status detected by NGS and/or IHC is reliable in identifying patients with ALK-positive NSCLC who will benefit from ALK inhibitor therapy.

Key considerations for comprehensive validation of an RNA fusion NGS panel

Objectives

Validation of RNA-based NGS assays for the detection of therapeutically targetable gene fusions is challenging. Here, we report systematic validation and quality control monitoring of our targeted fusion panel for the detection of 17 clinically relevant fusion transcripts across several tumor types. We implemented this RNA Fusion Panel as a reflex test for tumors lacking DNA driver mutations.

Design

Forty-four formalin-fixed, paraffin-embedded (FFPE) or fresh-frozen lung, brain, soft tissue and skin tumors were used to determine the accuracy of the assay. Additional fusion-positive specimens and a calibrated reference standard were used to establish the precision, reproducibility and sensitivity of the assay. All aspects of the validation, including quality control metrics, were performed according to New York State guidelines.

Results

For the RNA fusion panel, accuracy, reproducibility and precision studies were above 99%. Reproducibility and sensitivity studies with the reference standard were helpful in identifying inconsistencies. The limit of detection for most RNA fusion transcripts was 50 copies. Application of the RNA fusion assay as a reflex test to 450 tumor samples lacking DNA driver mutations resulted in a 10% increase in diagnostic yield with minimal additional processing time.

Conclusions

The validated RNA fusion panel provides clinical utility in therapy selection for patients with solid tumors. By using a sequential testing approach, the RNA fusion assay complements the DNA hotspot assay in identifying clinically relevant variants across many tumor types with minimal additional increase in processing time.

•

RNA fusion NGS panel uses anchored multiplex PCR to detect known and novel fusions.

•

Pre- and post-sequencing quality control increases accuracy of results.

•

Sequential testing of RNA, on samples without DNA variants is practical and cost-effective.

•

Detection of novel RNA fusions expands the therapeutic landscape of tumors.

Investigation on the prognostic impact of concurrent genomic alterations in crizotinib-treated EML4-ALK-rearranged advanced non-small cell lung cancer patients

BACKGROUND

Despite the efficacy of crizotinib in non-small cell lung cancer (NSCLC) with genomic rearrangement between echinoderm microtubule-associated protein-like 4 (EML4) and anaplastic lymphoma kinase (ALK), clinical outcomes are heterogeneous among these patients. In our study, we investigated concurrent molecular factors that could contribute to the heterogeneity of their clinical outcomes to crizotinib therapy.

METHODS

We retrospectively analyzed the clinical and targeted sequencing data from 32 crizotinib-treated patients with EML4-ALK-rearranged advanced NSCLC.

RESULTS

Analysis of the mutation profile revealed the detection of concurrent deleterious mutations in 17 patients (53 %, 17/32). Of which, 5 patients had deleterious copy number variations and 12 patients had deleterious single nucleotide variations. Seven patients did not harbor any concurrent mutations from the genes included in the panel. The remaining 8 patients harbored concurrent mutations which were either non-deleterious or variants of uncertain significance. TP53, detected from 34 % (11/32) of the patients and the most commonly co-occurring mutation in our cohort, was not significantly associated with survival outcomes. Interestingly, significantly shorter progression-free survival (P = 0.032) was observed in patients harboring concurrent deleterious mutations, particularly copy number amplifications (PFS, P = 0.0021; OS, P = 0.034), than those without concurrent deleterious mutations. Harboring more copy number variations, reflected by chromosomal fluctuation coefficient varscore, was associated with shorter progression-free survival (P = 0.02).

CONCLUSION

Our study revealed that concurrent deleterious mutations, particularly copy number amplifications in oncogenic genes have prognostic implications in patients with EML4-ALK-rearranged NSCLC receiving crizotinib therapy. These observations advance the understanding of the heterogeneity of treatment responses among patients with EML4-ALK-rearranged tumors.

Association of Programmed Death-Ligand 1 Expression with Fusion Variants and Clinical Outcomes in Patients with Anaplastic Lymphoma Kinase-Positive Lung Adenocarcinoma Receiving Crizotinib

BACKGROUND

Programmed death-ligand 1 (PD-L1) expression is associated with clinical outcomes of epidermal growth factor receptor (EGFR) mutant lung adenocarcinoma (ADC) treated with tyrosine kinase inhibitors (TKIs). However, whether PD-L1 expression plays a role in anaplastic lymphoma kinase (ALK)-positive lung ADC is unknown. We aimed to evaluate the impact of PD-L1 in patients with ALK-positive lung ADC receiving crizotinib.

MATERIALS AND METHODS

PD-L1 expression was identified by immunohistochemistry (IHC). Reverse transcriptase-polymerase chain reaction was used for ALK variant detection, and immunofluorescence-based multiplex staining was applied for exploring immune cells in tumor microenvironments.

RESULTS

A total of 78 patients with ALK-positive advanced ADC were enrolled in our study, of whom 52 received crizotinib. Compared with EGFR/ALK wild-type tumors, PD-L1 expression was lower in ALK-positive ADC. ALK fusion variants were identified in 32 patients, and those with variant 3 and 5 (short variants) had higher PD-L1 expression than those with other variants. The crizotinib objective response rate (ORR) and progression-free survival (PFS) was better in tumors with negative PD-L1 expression (ORR/PFS in PD-L1 0% vs. 1%-49% vs. 50%-100%: 60.7%/11.8 months vs. 38.5%/6.5 months vs. 36.4%/4.0 months, p = .007/.022). The multivariate Cox proportional hazards model revealed that PD-L1 0% (vs. ≥1%) was an independent factor for longer PFS (adjusted hazard ratio 0.322, 95% confidence interval 0.160-0.650, p = .002). Multiplex IHC in three cases showed a varied extent of immune cell infiltrations in tumors with different PD-L1 expression.

CONCLUSION

Positive PD-L1 expression was associated with unfavorable clinical outcomes in patients with ALK-positive lung ADC receiving crizotinib.

IMPLICATIONS FOR PRACTICE

Not all lung adenocarcinoma with sensitizing driver mutations experienced durable responses to small-molecule tyrosine kinase inhibitors (TKIs). Similar to the negative impact of programmed death-ligand 1 (PD-L1) in epidermal growth factor receptor mutant tumors treated with TKIs, this study demonstrated that positive PD-L1 expression was also associated with worse response rate and shorter progression-free survival of anaplastic lymphoma kinase (ALK)-positive adenocarcinoma treated with crizotinib. Among different ALK fusion partners, tumors with short variants (V3 and V5) had higher PD-L1 compared with long variants (V1, V2, and V6). Testing PD-L1 before initiating crizotinib for ALK-positive lung cancer could be a simple method to provide important prognostic information.

Detection of Targetable Genetic Alterations in Korean Lung Cancer Patients: A Comparison Study of Single-Gene Assays and Targeted Next-Generation Sequencing

PURPOSE

Epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), and ROS proto-oncogene 1 (ROS1) are 'must-test' biomarkers in the molecular diagnostics of advanced-stage lung cancer patients. Although single-gene assays are currently considered the gold standard for these genes, next-generation sequencing (NGS) tests are being introduced to clinical practices. We compared the results of current diagnostics and aimed to suggest timely effective guidance for their clinical use.

MATERIALS AND METHODS

Patients with lung cancer who received both conventional single-gene assays and subsequent targeted NGS testing were enrolled, and the results of their tests were compared.

RESULTS

A total of 241 patients were enrolled, and the EGFR real-time polymerase chain reaction, ALK fluorescence in situ hybridization (FISH), and ROS1 FISH assays exhibited 92.9%, 99.6%, and 99.5% concordance with the NGS tests, respectively. The discordant cases were mostly false-negatives of the single-gene assays, probably due to technical limitation. Of 158 cases previously designated as wild-type, EGFR, ALK, and ROS1 alterations were identified in 10.1%, 1.9%, and 1.3%, respectively, and other targetable alterations were identified in 36.1% of the cases. Of patients with additionally identified actionable alterations, 32.6% (31/95) received matched therapy with a clinical benefit of 48.4% (15/31).

CONCLUSION

Even though the conventional and NGS methods were concordant in the majority of cases, NGS testing still revealed a considerable number of additional EGFR, ALK, and ROS1 alterations, as well as other targetable alterations, in Korean advanced-stage lung cancer patients. Given the high frequency of EGFR and other targetable mutations identified in the present study, NGS testing is highly recommended in the diagnosis of Korean lung cancer patients.

Anaplastic Lymphoma Kinase Mutation-Positive Non-Small Cell Lung Cancer

The treatment of patients with advanced non-small cell lung cancer with anaplastic lymphoma kinase chromosomal rearrangements has been revolutionized by the development of tyrosine kinase inhibitors (TKIs). Excellent progress has been made over the past decade, with 4 TKIs now approved in the front-line setting. Alectinib is the preferred first-line option based on its efficacy and side-effect profile. The central nervous system (CNS) activity of alectinib and brigatinib has allowed for treatment of CNS metastases with TKI therapy. Once resistance inevitably develops, newer therapies such as lorlatinib can be considered.

Detection of Nonreciprocal/Reciprocal ALK Translocation as Poor Predictive Marker in Patients With First-Line Crizotinib-Treated ALK-Rearranged NSCLC

INTRODUCTION

During nonreciprocal/reciprocal translocation process, 5'-anaplastic lymphoma kinase (ALK) sometimes gets retained in the genome and is detectable by next-generation sequencing; however, no study has investigated its clinical significance. Our study aimed to assess the impact of harboring 5'-ALK on the efficacy of crizotinib.

METHODS

A total of 150 patients with next-generation sequencing-identified ALK-rearranged NSCLC from March 2014 to July 2018 at the Hunan Cancer Hospital were enrolled in this study. The efficacy of crizotinib as first-line therapy was evaluated in 112 patients according to the retention of 5'-ALK.

RESULTS

Among the 150 patients with NSCLC, nonreciprocal/reciprocal translocation was detected in 18.7% (28 of 150), and 3'-ALK fusion alone was detected in 81.3% (122 of 150). Among the 112 patients who received first-line crizotinib, 89 had 3'-ALK fusion alone (79 echinoderm microtubule associated protein-like 4 [EML4]-ALK and 10 non-EML4-ALK), and 23 had nonreciprocal/reciprocal ALK translocation. Among the patients with nonreciprocal/reciprocal ALK translocation, three patients harbored dual concurrent 3'-ALK fusions. Patients with nonreciprocal/reciprocal ALK translocation had higher incidence of brain metastasis at baseline than those with 3'-ALK fusion alone (39.1% versus 13.4%, p = 0.028). Crizotinib-treated patients with nonreciprocal/reciprocal ALK translocation had significantly shorter median progression-free survival (PFS) compared with patients carrying 3'-ALK fusion alone (6.1 m versus 12.0 m, p = 0.001) or with EML4-ALK fusion alone (6.1 m versus 12.6 m, p = 0.001). Multivariate analysis revealed that harboring nonreciprocal/reciprocal ALK translocation was an independent predictor of worse PFS for crizotinib-treated ALK-rearranged NSCLC (p = 0.0046).

CONCLUSIONS

Presence of nonreciprocal/reciprocal ALK translocation was predictive for worse PFS and greater likelihood of baseline brain metastases in patients with ALK-rearranged NSCLC who received first-line crizotinib.

Rapid detection and genotyping of ALK fusion variants by adapter multiplex PCR and high-resolution melting analysis

Anaplastic lymphoma kinase (ALK) fusion is a promising predictive biomarker of ALK-tyrosine kinase inhibitor (ALK-TKI) treatment. Furthermore, different fusion variants correlate to different ALK-TKIs responses. Although variant identification assists in treatment direction, most ALK detection assays do not genotype different fusion variants. We developed a high-resolution melting (HRM) assay to rapidly detect ALK fusions and automatically distinguish at least 20 fusion variants in one tube. Adapter multiplex PCR was designed to amplify ALK fusion variants and the reference gene GAPDH. After HRM, negative derivative curves showed a low temperature GAPDH peak, and if an ALK fusion was present, a high temperature peak from the ALK segment and variably a middle temperature part associated with the fusion partner. Selected regions of the second derivative curves were analyzed to extract features (∆T_m, PTS/ITS, H₁/H₂) that define two curve types (monotonic and non-monotonic). Synthetic samples of 20 ALK fusion variants were used to train a quadratic discriminate analysis model, and the accuracy was 97.06% (66/68) and 85.71% (144/162) for monotonic and non-monotonic variants, respectively. The limit of detection of the assay was 1%. The analytical sensitivity of genotyping was 1 and 5% for monotonic and non-monotonic variants, respectively. In a blinded study, we detected ALK fusion from formalin-fixed paraffin-embedded lung cancer samples with a 100% 47) and genotyping /47) and genotyping (7/7). Multiplex adapter HRM is a simple, fast, and sensitive way of ALK fusion detection and genotyping. Automatic genotyping with parameters extracted from second derivative curves is a promising method that may be applicable to other types of gene variants detected by HRM.

Genomic Profiling Reveals Synchronous Bilateral Lung Adenocarcinomas With Distinct Driver Alterations of EML4-ALK or TPM3-ROS1 Fusion: A Case Report

Background:ALK and ROS1 rearrangement accounts for 3–6% and 1–3% of non-small cell lung cancers, respectively, while coexistence of them in the same patient is extremely rare. Only three cases have ever been reported with concurrent ALK/ROS1 fusions in the same tumor indicating tumor heterogeneity. Therefore, comprehensive genetic profiling via next-generation sequencing (NGS) is needed to provide fully molecular diagnosis.

Case Presentation: A 50-year old Chinese female with resectable stage IB bilateral lung adenocarcinomas (ADCs) harbored EML4 exon 6-ALK exon 19 and TPM3 exon 8-ROS1 exon 35 fusions in the right lower and the left upper tumors, respectively, identified by clinical NGS test targeting 425 cancer-relevant genes. The results were further confirmed at RNA level using RNA-seq. Genomic evolution analysis reveals that these bilateral tumors are synchronous multiple primary lung cancers with no shared somatic alterations for both genes and arm-level copy number variations (CNVs). No recurrence was observed during 12 months of post-surgery follow-up.

Conclusions: Our case is the first report of concurrent ALK/ROS1 fusions as distinct driver events of synchronous multiple primary lung cancers, and highlights the importance of individual genetic testing for each of the multiple primary tumors for fully molecular diagnosis and precise treatment decision-making.

Role of liquid biopsy in oncogene-addicted non-small cell lung cancer

The discovery of actionable oncogene in non-small cell lung cancer (NSCLC) allowed the identification of a subgroup of patients who benefit from targeted tyrosine kinase inhibitors more than others. Mutations in the epidermal growth factor receptor (EGFR), translocations in the anaplastic lymphoma kinase (ALK) and rearrangements in the ROS proto-oncogene 1 (ROS1) must be identified in tumor tissue to guide the proper treatment choice. Liquid biopsy is based on the analysis of tumor materials released in the circulation. Liquid biopsy can be complementary to tissue biopsy, both at baseline and at progression, especially in the detection of somatic gene alterations emerging during the treatment with tyrosine kinase inhibitors (TKIs). Particularly, circulating DNA is used to find mutations in driver oncogenes, while circulating tumor cells, extracellular vesicles (EVs) and cell-free microRNAs (cfmiRNAs) are still under investigation. To help the unbiased use of liquid biopsy in the choice of the appropriate therapy, some recommendations were delivered by expert panels. Currently, analysis of EGFR mutations in cell-free DNA (cfDNA) is recommended at baseline when tissue biopsy harbors scarce tumor cells, and at progression before performing tissue biopsy; liquid biopsy analysis for other oncogenic drivers is not indicated in the clinical practice.