Phil Stephens

Identification of Recurrent FGFR3–TACC3 Fusion Oncogenes from Lung Adenocarcinoma

Purpose: Targetable oncogenic alterations are detected more commonly in patients with non–small cell lung cancer (NSCLC) who never smoked cigarettes. For such patients, specific kinase inhibitors have emerged as effective clinical treatments. However, the currently known oncogenic alterations do not account for all never smokers who develop NSCLC. We sought to identify additional oncogenic alterations from patients with NSCLC to define additional treatment options. Experimental Design: We analyzed 576 lung adenocarcinomas from patients of Asian and Caucasian ethnicity. We identified a subset of cancers that did not harbor any known oncogenic alteration. We performed targeted next-generation sequencing (NGS) assay on 24 patients from this set with >75% tumor cell content. Results: EGFR mutations were the most common oncogenic alteration from both Asian (53%) and Caucasian (41.6%) patients. No known oncogenic alterations were present in 25.7% of Asian and 31% of Caucasian tumor specimens. We identified a FGFR3–TACC3 fusion event in one of 24 patients from this subset using targeted NGS. Two additional patients harboring FGFR3–TACC3 were identified by screening our entire cohort (overall prevalence, 0.5%). Expression of FGFR3–TACC3 led to IL3 independent growth in Ba/F3 cells. These cells were sensitive to pan-fibroblast growth factor receptor (pan-FGFR) inhibitors but not the epidermal growth factor (EGFR) inhibitor gefitinib. Conclusions: FGFR3–TACC3 rearrangements occur in a subset of patients with lung adenocarcinoma. Such patients should be considered for clinical trials featuring FGFR inhibitors. Clin Cancer Res; 20(24); 6551–8. ©2014 AACR.

Comprehensive Genomic Profiling Identifies a Subset of Crizotinib-Responsive ALK-Rearranged Non-Small Cell Lung Cancer Not Detected by Fluorescence In Situ Hybridization

INTRODUCTION For patients with non-small cell lung cancer (NSCLC) to benefit from ALK inhibitors, sensitive and specific detection of ALK genomic rearrangements is needed. ALK break-apart fluorescence in situ hybridization (FISH) is the U.S. Food and Drug Administration approved and standard-of-care diagnostic assay, but identification of ALK rearrangements by other methods reported in NSCLC cases that tested negative for ALK rearrangements by FISH suggests a significant false-negative rate. We report here a large series of NSCLC cases assayed by hybrid-capture-based comprehensive genomic profiling (CGP) in the course of clinical care. MATERIALS AND METHODS Hybrid-capture-based CGP using next-generation sequencing was performed in the course of clinical care of 1,070 patients with advanced lung cancer. Each tumor sample was evaluated for all classes of genomic alterations, including base-pair substitutions, insertions/deletions, copy number alterations and rearrangements, as well as fusions/rearrangements. RESULTS A total of 47 patients (4.4%) were found to harbor ALK rearrangements, of whom 41 had an EML4-ALK fusion, and 6 had other fusion partners, including 3 previously unreported rearrangement events: EIF2AK-ALK, PPM1B-ALK, and PRKAR1A-ALK. Of 41 patients harboring ALK rearrangements, 31 had prior FISH testing results available. Of these, 20 were ALK FISH positive, and 11 (35%) were ALK FISH negative. Of the latter 11 patients, 9 received crizotinib based on the CGP results, and 7 achieved a response with median duration of 17 months. CONCLUSION Comprehensive genomic profiling detected canonical ALK rearrangements and ALK rearrangements with noncanonical fusion partners in a subset of patients with NSCLC with previously negative ALK FISH results. In this series, such patients had durable responses to ALK inhibitors, comparable to historical response rates for ALK FISH-positive cases. IMPLICATIONS FOR PRACTICE Comprehensive genomic profiling (CGP) that includes hybrid capture and specific baiting of intron 19 of ALK is a highly sensitive, alternative method for identification of drug-sensitive ALK fusions in patients with non-small cell lung cancer (NSCLC) who had previously tested negative using standard ALK fluorescence in situ hybridization (FISH) diagnostic assays. Given the proven benefit of treatment with crizotinib and second-generation ALK inhibitors in patients with ALK fusions, CGP should be considered in patients with NSCLC, including those who have tested negative for other alterations, including negative results using ALK FISH testing.

Durable Response to Crizotinib in a MET-Amplified, KRAS-Mutated Carcinoma of Unknown Primary

Background: Carcinoma of unknown primary (CUP) accounts for 3-5% of all adult solid tumors. An extensive search for the anatomic site of origin is often undertaken in an attempt to tailor systemic treatment, but the latter often has limited efficacy - especially in the setting of an initial treatment failure. Molecularly targeted therapy is an emerging approach that may offer greater efficacy and less toxicity but is most likely to be effective when pairing a tumor harboring a sensitizing genomic alteration with an agent directed at the altered gene product. We report a patient with a CUP harboring a MET amplification with a complete metabolic response to crizotinib despite also harboring a KRAS mutation. Methods: Genomic profiling was performed using a clinical next-generation-sequencing-based assay, FoundationOne®, in a CAP-accredited laboratory certified by Clinical Laboratory Improvement Amendments (Foundation Medicine, Cambridge, Mass., USA). Results: The CUP harbored both MET amplification (16 copies) and a KRAS G12V mutation. The patient was treated with crizotinib, a MET inhibitor, and has experienced a complete normalization of tumor metabolic activity for more than 19 months. Conclusions: Genomic profiling of CUP may reveal clinically meaningful genomic alterations that can guide targeted therapy decision-making. The use of this approach should be studied prospectively as a strategy for the effective treatment of CUP patients and for avoiding resource-intensive workups to identify the tumor site of origin.

Patient-derived xenotransplants can recapitulate the genetic driver landscape of acute leukemias.

Genomic studies have identified recurrent somatic mutations in acute leukemias. However, current murine models do not sufficiently encompass the genomic complexity of human leukemias. To develop preclinical models, we transplanted 160 samples from patients with acute leukemia (acute myeloid leukemia, mixed lineage leukemia, B-cell acute lymphoblastic leukemia, T-cell ALL) into immunodeficient mice. Of these, 119 engrafted with expected immunophenotype. Targeted sequencing of 374 genes and 265 frequently rearranged RNAs detected recurrent and novel genetic lesions in 48 paired primary tumor (PT) and patient-derived xenotransplant (PDX) samples. Overall, the frequencies of 274 somatic variant alleles correlated between PT and PDX samples, although the data were highly variable for variant alleles present at 0–10%. Seventeen percent of variant alleles were detected in either PT or PDX samples only. Based on variant allele frequency changes, 24 PT-PDX pairs were classified as concordant while the other 24 pairs showed various degree of clonal discordance. There was no correlation of clonal concordance with clinical parameters of diseases. Significantly more bone marrow samples than peripheral blood samples engrafted discordantly. These data demonstrate the utility of developing PDX banks for modeling human leukemia, and emphasize the importance of genomic profiling of PDX and patient samples to ensure concordance before performing mechanistic or therapeutic studies.

Tumor-specific HSP90 inhibition as a therapeutic approach in JAK-mutant acute lymphoblastic leukemias.

The development of the dual Janus kinase 1/2 (JAK1/2) inhibitor ruxolitinib for the treatment of myeloproliferative neoplasms (MPNs) has led to studies of ruxolitinib in other clinical contexts, including JAK-mutated acute lymphoblastic leukemia (ALL). However, the limited ability of JAK inhibition to induce molecular or clinicopathological responses in MPNs suggests a need for development of better therapies for JAK kinase-dependent malignancies. Here, we demonstrate that heat shock protein 90 (HSP90) inhibition using a purine-scaffold HSP90 inhibitor in early clinical development is an effective therapeutic approach in JAK-dependent ALL and can overcome persistence to JAK-inhibitor therapy in ALL cells.

Extended Antitumor Response of a BRAF V600E Papillary Thyroid Carcinoma to Vemurafenib.

Context: For patients with metastatic papillary thyroid carcinoma (PTC) refractory to radioactive iodine (RAI) treatment, systemic chemotherapy has limited efficacy. Such tumors frequently harbor BRAF V600E, and this alteration may predict responsiveness to vemura-fenib treatment. Objective: We report a metastatic PTC patient refractory to RAI treatment that underwent genomic profiling by next-generation sequencing. The sole genomic alteration identified was BRAF V600E on a near diploid genome with trisomy 1q. With vemurafenib treatment, the patient experienced a dramatic radiographic and clinical improvement, with the duration of an ongoing antitumor response exceeding 23 months. Design: Hybridization capture of 3,769 exons of 236 cancer-related genes and the introns of 19 genes frequently rearranged in cancer was applied to >50 ng of DNA extracted from a formalin-fixed, paraffin-embedded biopsy of a lymph node containing metastatic PTC and was sequenced to a high, uniform coverage of ×616. Results: A BRAF V600E alteration was identified with no other somatic genomic alterations present within a near diploid tumor genome. The patient initially received vemurafenib at 960 mg twice daily that was reduced to 480 mg twice daily due to rash and diarrhea and has experienced an ongoing antitumor response exceeding 23 months by both PET-CT and dedicated CT imaging. Conclusions: Genomic profiling in metastatic, RAI-refractory PTC can reveal a targetable BRAF V600E alteration without compounding somatic alterations, and such patients may derive a more prolonged benefit from vemurafenib treatment. Prospective clinical trials are ongoing to confirm our preliminary observation.

Comparing two assays for clinical genomic profiling: the devil is in the data.

Dear editor We read with concern the paper “Evaluation and comparison of two commercially available targeted next-generation sequencing platforms to assist oncology decision-making”.1 The study directly compared results for the Paradigm Cancer Diagnostic test to the FoundationOne test for formalin-fixed, paraffin-embedded specimen pairs from 21 advanced cancer cases. We believe this study is fundamentally flawed, misleading, and potentially dangerous for patient care, for the reasons outlined herein. The paper neglected to address innumerable discordances between a rigorously analytically validated test (FoundationOne) and the experimental assay. It erroneously ascribes categorization of many genomic alterations detected on FoundationOne as “none”, when in fact available drugs have demonstrated activity or mechanism-based clinical trials exist, and it claims high levels of actionability based on the results of RNA-expression profiling of a single gene – TOPO2A. This study is notable for a remarkable lack of concordance between the genomic alterations detected on each platform, even in genes common to both assays. For the majority of specimens, there were no genomic alterations in common, and only six of 21 samples shared a single alteration, matching at the gene level. Paradigm DNA-based testing found only two cases wherein a result was labeled by them as “commercially available” or “clinical trial”, an EGFR mutation in a lung adenocarcinoma, and a KIT mutation in a colon adenocarcinoma. This KIT mutation was not detected by FoundationOne. Similarly, lack of concordance is noted for mutations in ARID1A (case 1), PDGFRA and PI3K (case 2), KRAS, PI3K and PTEN (case 5), PTEN and ARID1A (case 6), EGFR amplification (case 9), ERBB2 (cases 12, 14), and PI3K (case 19). Given the significant discordance in the genomic alterations detected and reported, it must reasonably be concluded that at least one assay has extremely poor mutation-detection performance. FoundationOne underwent an extensive 2-year analytic validation study. This study rigorously demonstrated the test’s high-performance characteristics.2 The Paradigm assay has no published analytic validation studies. The lack of concordance between the two platforms calls into serious question the performance of the Paradigm assay and the validity of the data. Clinical activity and/or mechanism-directed trials exist for genomic (DNA-based) alterations in PTEN,3 RICTOR,4 CDK6 (NCT02187783), FGFR4 (NCT02325739), ERRFI1,5 FBXW7,6 and PI3KR1 (NCT01971515). The “actionable target” determination, as displayed in Table 2, also reveals a failure to acknowledge KRAS as a gene for which therapeutic approaches exist in clinical trials, and for which prior genomically driven trials have shown selected activity.7 Although an acknowledged therapeutic challenge, KRAS-mutated tumors have been the object of no fewer than 26 clinical trials with targeted agents requiring a KRAS mutation as molecular eligibility entry criteria (www.ClinicalTrials.gov). Despite this, all of these genes are scored as “none” as shown in Table 2, column two.1 The authors report RNA alterations linked to potential therapeutic intervention in 16 of 21 cases: eleven with TOPO2A overexpression alone, four with ERBB2 over-expression alone, and one case with both; however, in only two of five cases was ERBB2 amplification detected by FoundationOne, an assay that has undergone rigorous concordance testing with the gold-standard assays of fluorescence in situ hybridization and immunohistochemistry. TOPO2A overexpression was present in six of six lung adenocarcinomas. Unfortunately, this result is not surprising or helpful, as anthracyclines have no reproducible activity in NSCLC, ie, the results provide no useful clinical information. Furthermore, it is well known that TOPO2A expression is regulated by the cell cycle8 and is independent of TOPO2A gene amplification.9 It is TOPO2A gene amplification, not TOPO2A expression, that has been linked in some but not all studies as a biomarker of anthracycline efficacy in breast cancer.10 In order to permit a fully informed comparison between commercial cancer genome-profiling assays, we believe it necessary for all parties to make public most aspects of their test methodology and data. In this case, we believe the authors need to publish all aspects of the testing methodology for the Paradigm Cancer Diagnostic test. For example, which exons of which genes are targeted in this test? Is the test achieving high, even coverage of target regions? Are reported sequence coverage metrics from unique input DNA molecules and not PCR duplicates? Are appropriate computational methods employed? None of these critical questions can be evaluated with the information provided. Oncologists increasingly rely upon results of comprehensive genomic profiling in making important treatment decisions. For this reason, rigorous peer-reviewed validation of genomic tests offered for use in clinical applications is essential. We believe the Paradigm study does not meet this standard and is sufficiently flawed such that we encourage the authors to consider retracting the paper.

A Poorly Differentiated Malignant Neoplasm Lacking Lung Markers Harbors an EML4-ALK Rearrangement and Responds to Crizotinib

Suspected metastatic site lesions that are poorly differentiated present a diagnostic challenge when morphologic and immunohistochemical profiling cannot establish the primary tumor site. Here we present a patient diagnosed with both a malignant neoplasm in the lung and a right upper extremity (RUE) neoplasm of unclear histogenetic origin. Immunohistochemical staining performed on the latter specimen was inconclusive in determining the site of origin. Although the lung biopsy sample was insufficient for molecular testing, hybrid capture-based comprehensive genomic profiling (FoundationOne) identified an EML4-ALK rearrangement in the RUE lesion. Crizotinib treatment resulted in a major response in both the RUE and the lung lesions. This report illustrates the utility of comprehensive genomic profiling employed at the initial presentation of an unknown primary malignant neoplasm, which resulted in the front-line use of targeted therapy and a significant and sustained antitumor response.

BRAF in Lung Cancers: Analysis of Patient Cases Reveals Recurrent BRAF Mutations, Fusions, Kinase Duplications, and Concurrent Alterations

Purpose Dabrafenib and trametinib are approved for the management of advanced non-small-cell lung cancers (NSCLCs) that harbor BRAF V600E mutations. Small series and pan-cancer analyses have identified non-V600 alterations as therapeutic targets. We sought to examine a large genomic data set to comprehensively characterize non-V600 BRAF alterations in lung cancer. Patients and Methods A total of 23,396 patients with lung cancer provided data to assay with comprehensive genomic profiling. Data were reviewed for predicted pathogenic BRAF base substitutions, short insertions and deletions, copy number changes, and rearrangements. Results Adenocarcinomas represented 65% of the occurrences; NSCLC not otherwise specified (NOS), 15%; squamous cell carcinoma, 12%; and small-cell lung carcinoma, 5%. BRAF was altered in 4.5% (1,048 of 23,396) of all tumors; 37.4% (n = 397) were BRAF V600E, 38% were BRAF non-V600E activating mutations, and 18% were BRAF inactivating. Rearrangements were observed at a frequency of 4.3% and consisted of N-terminal deletions (NTDs; 0.75%), kinase domain duplications (KDDs; 0.75%), and BRAF fusions (2.8%). The fusions involved three recurrent fusion partners: ARMC10, DOCK4, and TRIM24. BRAF V600E was associated with co-occurrence of SETD2 alterations, but other BRAF alterations were not and were instead associated with CDKN2A, TP53, and STK11 alterations (P < .05). Potential mechanisms of acquired resistance to BRAF V600E inhibition are demonstrated. Conclusion This series characterized the frequent occurrence (4.4%) of BRAF alterations in lung cancers. Recurrent BRAF alterations in NSCLC adenocarcinoma are comparable to the frequency of other NSCLC oncogenic drivers, such as ALK, and exceed that of ROS1 or RET. This work supports a broad profiling approach in lung cancers and suggests that non-V600E BRAF alterations represent a subgroup of lung cancers in which targeted therapy should be considered.

Exceptional durable response to everolimus in a patient with biphenotypic breast cancer harboring an STK11 variant

Metastatic triple-negative breast cancer comprises 12%–17% of breast cancers and carries a poor prognosis relative to other breast cancer subtypes. Treatment options in this disease are largely limited to systemic chemotherapy. A majority of clinical studies assessing efficacy of targeted therapeutics (e.g., the mammalian target of rapamycin [mTOR] inhibitor everolimus) in advanced breast cancer patients have not utilized predictive genomic biomarker-based selection and have reported only modest improvement in the clinical outcome relative to standard of care. However, recent reports have highlighted significant clinical responses of breast malignancies harboring alterations in genes involved in the phosphoinositide 3-kinase (PI3K)/AKT/mTOR signaling pathway to mTOR-inhibitor-involving regimens, underscoring the potential clinical benefit of treating subsets of breast cancer patients with molecularly matched targeted therapies. As the paradigm of cancer treatment shifts from chemotherapeutic regimens to more personalized approaches, the identification of additional reliable biomarkers is essential for identifying patients likely to derive maximum benefit from targeted therapies. Herein, we report a near-complete and ongoing 14-mo response to everolimus therapy of a heavily pretreated patient with biphenotypic, metastatic breast cancer. Genomic profiling of the metastatic triple-negative liver specimen identified a single reportable point mutation, STK11 F354L, that appears to have undergone loss of heterozygosity. No other alterations within the PI3K/mTOR pathway were observed. Published functional biochemical data on this variant are conflicting, and germline data, albeit with unclear zygosity status, are suggestive of a benign polymorphism role. Together with the preclinical data, this case suggests further investigation of this variant is warranted to better understand its role as a potential biomarker for mTOR inhibitor sensitivity in the appropriate clinical context.