Person:

Shaw, Alice

Inhibitors that target the receptor tyrosine kinase (RTK)/Ras/mitogen-activated protein kinase (MAPK) pathway have led to clinical responses in lung and other cancers, but some patients fail to respond and in those that do resistance inevitably occurs (Balak et al., 2006; Kosaka et al., 2006; Rudin et al., 2013; Wagle et al., 2011). To understand intrinsic and acquired resistance to inhibition of MAPK signaling, we performed CRISPR-Cas9 gene deletion screens in the setting of BRAF, MEK, EGFR, and ALK inhibition. Loss of KEAP1, a negative regulator of NFE2L2/NRF2, modulated the response to BRAF, MEK, EGFR, and ALK inhibition in BRAF-, NRAS-, KRAS-, EGFR-, and ALK-mutant lung cancer cells. Treatment with inhibitors targeting the RTK/MAPK pathway increased reactive oxygen species (ROS) in cells with intact KEAP1, and loss of KEAP1 abrogated this increase. In addition, loss of KEAP1 altered cell metabolism to allow cells to proliferate in the absence of MAPK signaling. These observations suggest that alterations in the KEAP1/NRF2 pathway may promote survival in the presence of multiple inhibitors targeting the RTK/Ras/MAPK pathway. DOI: http://dx.doi.org/10.7554/eLife.18970.001

A study reported in this issue of The Oncologist examined the utility of next-generation sequencing (NGS) in detecting ALK rearrangements. NGS may one day become the standard initial test for molecular genotyping of patients with advanced cancers, and this new generation of ALK diagnostics is a welcome addition to the current screening repertoire.

Glioneuronal tumors constitute a histologically diverse group of primary central nervous system neoplasms that are typically slow-growing and managed conservatively. Genetic alterations associated with glioneuronal tumors include BRAF mutations and oncogenic fusions. To further characterize this group of tumors, we collected a cohort of 26 glioneuronal tumors and performed in-depth genomic analysis. We identified mutations in BRAF (34%) and oncogenic fusions (30%), consistent with previously published reports. In addition, we discovered novel oncogenic fusions involving members of the NTRK gene family in a subset of our cohort. One-patient with BCAN exon 13 fused to NTRK1 exon 11 initially underwent a subtotal resection for a 4th ventricular glioneuronal tumor but ultimately required additional therapy due to progressive, symptomatic disease. Given the patient’s targetable fusion, the patient was enrolled on a clinical trial with entrectinib, a pan-Trk, ROS1, and ALK (anaplastic lymphoma kinase) inhibitor. The patient was treated for 11 months and during this time volumetric analysis of the lesion demonstrated a maximum reduction of 60% in the contrast-enhancing tumor compared to his pre-treatment magnetic resonance imaging study. The radiologic response was associated with resolution of his clinical symptoms and was maintained for 11 months on treatment. This report of a BCAN-NTRK1 fusion in glioneuronal tumors highlights its clinical importance as a novel, targetable alteration.

Purpose Crizotinib is a potent, orally administered tyrosine kinase inhibitor approved for the treatment of anaplastic lymphoma kinase (ALK)-positive advanced non-small-cell lung cancer (NSCLC). We report final results from PROFILE 1005, the largest clinical trial to date for an ALK inhibitor in ALK-positive NSCLC. Patients and methods PROFILE 1005 (NCT00932451) was a multicenter, single-arm phase 2 trial of the efficacy, safety and tolerability of crizotinib (250 mg twice daily; 3 week continuous treatment cycles) in patients with ALK-positive NSCLC after failure of ≥1 lines of systemic treatment for locally advanced/metastatic disease. Patients’ tumour ALK status was initially determined by a central laboratory until a protocol amendment permitted enrolment of patients based on locally determined ALK status. Co-primary endpoints were objective response rate (ORR), evaluated using Response Evaluation Criteria in Solid Tumours V.1.1 and adverse events (AEs). Cancer-specific patient-reported outcomes (PROs) were also assessed using the European Organisation for the Research and Treatment of Cancer QLQ-C30 and its lung cancer module QLQ-LC13. Results: 1069 patients were enrolled; 1066 received crizotinib. The as-treated population comprised 908 and 158 patients, in whom tumour positive ALK-status was determined centrally (± locally) or locally only, respectively. At baseline, a majority of patients were <65 years (84%), 66% were never smokers and 46% were Asian. Derived investigator-assessed ORR was 54% (95% CI 51 to 57) and 41% (95% CI 33 to 49) in the central-testing and local-testing subgroups, respectively. The most common treatment-related AEs in the overall population (any grade) were vision disorder (58%), nausea (51%), diarrhoea (47%) and vomiting (47%). PRO scores demonstrated clinically meaningful improvement in lung cancer symptoms and global quality of life. Conclusion: The efficacy, safety and PRO profiles of crizotinib in this cohort of 1066 patients with ALK-positive NSCLC are consistent with previous reports. Trial registration number Phase 2 trial (NCT00932451); Results.

Purpose The anaplastic large cell kinase gene (ALK) is rearranged in approximately 5% of lung adenocarcinomas within the Asian population. We evaluated the incidence and the characteristics of ALK-rearranged lung adenocarcinomas within the Western population and the optimal diagnostic modality to detect ALK rearrangements in routine clinical practice.

Experimental Design We tested 358 lung adenocarcinomas from three institutions for ALK rearrangements by fluorescent in-situ hybridization (FISH) and immunohistochemistry (IHC) with and without tyramide amplification (TA). The clinicopathologic characteristics of tumors with and without ALK rearrangements were compared.

Results We identified 20 lung adenocarcinomas (5.6%) with ALK rearrangements within our cohort of Western patients. ALK rearrangement was associated with younger age (P = 0.0002), never smoking (P < 0.0001), advanced clinical stage (P = 0.0001), and a solid histology with signet-ring cells (P < 0.0001). ALK rearrangement was identified by FISH in 95% of cases, IHC with and without TA in 80% and 40% of cases, respectively, but neither FISH nor IHC alone detected all cases with ALK rearrangement on initial screening. None of the ALK-rearranged tumors harbored coexisting EGFR mutations.

Conclusions Lung adenocarcinomas with ALK rearrangements are uncommon in the Western population and represent a distinct entity of carcinomas with unique characteristics. For suspected cases dual diagnostic testing, with FISH and IHC, should be considered to accurately identify lung adenocarcinomas with ALK rearrangement.