Current Trial Report: A Multicenter Phase I/Ib study of Capmatinib Plus Trametinib in Patients With Metastatic Nonsmall Cell Lung Center Harboring MET Exon 14 Skipping Mutations and Other MET-Alterations.

INTRODUCTION: MET tyrosine kinase inhibitor (TKI) therapy is associated with improved outcomes in patients with nonsmall cell lung cancer (NSCLC) harboring a MET alteration, including MET exon 14 (METex14) skipping mutation, MET amplification, or MET fusion. However, primary or acquired resistance to TKI therapy ultimately develops. In preclinical models, hyperactivation of MAPK signaling was shown to promote resistance to MET TKI; resistance was overcome by co-treatment with a MET inhibitor and a MEK inhibitor. This phase I/Ib study offers a potential combination strategy simultaneously targeting MET (with capmatinib) and MEK signaling (with trametinib) to overcome resistance to MET inhibitor monotherapy in METex14 NSCLC. METHODS: In the dose escalation phase, a minimum of 6 and maximum of 18 patients will be enrolled using a conventional 3+3 design with the primary endpoint of identifying a recommended phase 2 dose (RP2D) of capmatinib in combination with trametinib. Once the RP2D is identified, patients will continue to enroll in a dose expansion phase to a total of 15 patients. The primary endpoint of the dose expansion phase is to further characterize the safety profile of the combination. CONCLUSION: This phase I/Ib clinical trial will assess the safety and efficacy of combination capmatinib and trametinib in NSCLC patients whose tumors harbor METex14 skipping mutations, MET amplification, or MET fusion and had developed progressive disease on single agent MET inhibitor therapy.

Neoadjuvant Osimertinib for the Treatment of Stage I-IIIA Epidermal Growth Factor Receptor-Mutated Non-Small Cell Lung Cancer: A Phase II Multicenter Study.

PURPOSE: To assess the safety and efficacy of the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor osimertinib as neoadjuvant therapy in patients with surgically resectable stage I-IIIA EGFR-mutated non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: This was a multi-institutional phase II trial of neoadjuvant osimertinib for patients with surgically resectable stage I-IIIA (American Joint Committee on Cancer [AJCC] V7) EGFR-mutated (L858R or exon 19 deletion) NSCLC (ClinicalTrials.gov identifier: NCT03433469). Patients received osimertinib 80 mg orally once daily for up to two 28-day cycles before surgical resection. The primary end point was major pathological response (MPR) rate. Secondary safety and efficacy end points were also assessed. Exploratory end points included pretreatment and post-treatment tumor mutation profiling. RESULTS: A total of 27 patients were enrolled and treated with neoadjuvant osimertinib for a median 56 days before surgical resection. Twenty-four (89%) patients underwent subsequent surgery; three (11%) patients were converted to definitive chemoradiotherapy. The MPR rate was 14.8% (95% CI, 4.2 to 33.7). No pathological complete responses were observed. The ORR was 52%, and the median DFS was 40.9 months. One treatment-related serious adverse event (AE) occurred (3.7%). No patients were unable to undergo surgical resection or had surgery delayed because of an AE. The most common co-occurring tumor genomic alterations were in TP53 (42%) and RBM10 (21%). CONCLUSION: Treatment with neoadjuvant osimertinib in surgically resectable (stage IA-IIIA, AJCC V7) EGFR-mutated NSCLC did not meet its primary end point for MPR rate. However, neoadjuvant osimertinib did not lead to unanticipated AEs, surgical delays, nor result in a significant unresectability rate.

Mixed responses to targeted therapy driven by chromosomal instability through p53 dysfunction and genome doubling.

The phenomenon of mixed/heterogenous treatment responses to cancer therapies within an individual patient presents a challenging clinical scenario. Furthermore, the molecular basis of mixed intra-patient tumor responses remains unclear. Here, we show that patients with metastatic lung adenocarcinoma harbouring co-mutations of EGFR and TP53, are more likely to have mixed intra-patient tumor responses to EGFR tyrosine kinase inhibition (TKI), compared to those with an EGFR mutation alone. The combined presence of whole genome doubling (WGD) and TP53 co-mutations leads to increased genome instability and genomic copy number aberrations in genes implicated in EGFR TKI resistance. Using mouse models and an in vitro isogenic p53-mutant model system, we provide evidence that WGD provides diverse routes to drug resistance by increasing the probability of acquiring copy-number gains or losses relative to non-WGD cells. These data provide a molecular basis for mixed tumor responses to targeted therapy, within an individual patient, with implications for therapeutic strategies.

Focal adhesion kinase-YAP signaling axis drives drug-tolerant persister cells and residual disease in lung cancer.

Targeted therapy is effective in many tumor types including lung cancer, the leading cause of cancer mortality. Paradigm defining examples are targeted therapies directed against non-small cell lung cancer (NSCLC) subtypes with oncogenic alterations in EGFR, ALK and KRAS. The success of targeted therapy is limited by drug-tolerant persister cells (DTPs) which withstand and adapt to treatment and comprise the residual disease state that is typical during treatment with clinical targeted therapies. Here, we integrate studies in patient-derived and immunocompetent lung cancer models and clinical specimens obtained from patients on targeted therapy to uncover a focal adhesion kinase (FAK)-YAP signaling axis that promotes residual disease during oncogenic EGFR-, ALK-, and KRAS-targeted therapies. FAK-YAP signaling inhibition combined with the primary targeted therapy suppressed residual drug-tolerant cells and enhanced tumor responses. This study unveils a FAK-YAP signaling module that promotes residual disease in lung cancer and mechanism-based therapeutic strategies to improve tumor response.

Quantification of cerebrospinal fluid tumor DNA in lung cancer patients with suspected leptomeningeal carcinomatosis.

Cerebrospinal fluid tumor-derived DNA (CSF-tDNA) analysis is a promising approach for monitoring the neoplastic processes of the central nervous system. We applied a lung cancer-specific sequencing panel (CAPP-Seq) to 81 CSF, blood, and tissue samples from 24 lung cancer patients who underwent lumbar puncture (LP) for suspected leptomeningeal disease (LMD). A subset of the cohort (N = 12) participated in a prospective trial of osimertinib for refractory LMD in which serial LPs were performed before and during treatment. CSF-tDNA variant allele fractions (VAFs) were significantly higher than plasma circulating tumor DNA (ctDNA) VAFs (median CSF-tDNA, 32.7%; median plasma ctDNA, 1.8%; P < 0.0001). Concentrations of tumor DNA in CSF and plasma were positively correlated (Spearman's ρ, 0.45; P = 0.03). For LMD diagnosis, cytology was 81.8% sensitive and CSF-tDNA was 91.7% sensitive. CSF-tDNA was also strongly prognostic for overall survival (HR = 7.1; P = 0.02). Among patients with progression on targeted therapy, resistance mutations, such as EGFR T790M and MET amplification, were common in peripheral blood but were rare in time-matched CSF, indicating differences in resistance mechanisms based on the anatomic compartment. In the osimertinib cohort, patients with CNS progression had increased CSF-tDNA VAFs at follow-up LP. Post-osimertinib CSF-tDNA VAF was strongly prognostic for CNS progression (HR = 6.2, P = 0.009). Detection of CSF-tDNA in lung cancer patients with suspected LMD is feasible and may have clinical utility. CSF-tDNA improves the sensitivity of LMD diagnosis, enables improved prognostication, and drives therapeutic strategies that account for spatial heterogeneity in resistance mechanisms.

Phase-Separated Biomolecular Condensation in Cancer: New Horizons and Next Frontiers.

SUMMARY: Beyond lipid membrane compartments, cells including cancer cells utilize various membraneless compartments, often termed biomolecular condensates, to regulate or organize key cellular processes underlying physiologic or pathologic phenotypes. In this commentary, the emergence of biomolecular condensation in cancer biology is highlighted, with a focus on key unanswered questions and with implications for improving the understanding of cancer pathogenesis and developing innovative cancer management strategies.

PERCEPTION predicts patient response and resistance to treatment using single-cell transcriptomics of their tumors.

Tailoring optimal treatment for individual cancer patients remains a significant challenge. To address this issue, we developed PERCEPTION (PERsonalized Single-Cell Expression-Based Planning for Treatments In ONcology), a precision oncology computational pipeline. Our approach uses publicly available matched bulk and single-cell (sc) expression profiles from large-scale cell-line drug screens. These profiles help build treatment response models based on patients' sc-tumor transcriptomics. PERCEPTION demonstrates success in predicting responses to targeted therapies in cultured and patient-tumor-derived primary cells, as well as in two clinical trials for multiple myeloma and breast cancer. It also captures the resistance development in patients with lung cancer treated with tyrosine kinase inhibitors. PERCEPTION outperforms published state-of-the-art sc-based and bulk-based predictors in all clinical cohorts. PERCEPTION is accessible at https://github.com/ruppinlab/PERCEPTION . Our work, showcasing patient stratification using sc-expression profiles of their tumors, will encourage the adoption of sc-omics profiling in clinical settings, enhancing precision oncology tools based on sc-omics.

Unlocking the EGFR-mediated epitranscriptome: A pathway to novel therapies.

In this issue, Lv et al.1 explore EGFR-driven epitranscriptomic reprogramming in glioblastoma, revealing the pivotal role of the EGFR-ALKBH5-GCLM axis in ferroptosis protection. Their findings offer mechanistic insight and therapeutic strategies involving novel combination targets to enhance tumor responses.

The essential chaperone DNAJC17 activates HSP70 to coordinate RNA splicing and G2-M progression.

Molecular chaperones including the heat-shock protein 70-kilodalton (HSP70) family and the J-domain containing protein (JDP) co-chaperones maintain homeostatic balance in eukaryotic cells through regulation of the proteome. The expansive JDP family helps direct specific HSP70 functions, and yet loss of single JDP-encoding genes is widely tolerated by mammalian cells, suggesting a high degree of redundancy. By contrast, essential JDPs might carry out HSP70-independent functions or fill cell-context dependent, highly specialized roles within the proteostasis network. Using a genetic screen of JDPs in human cancer cell lines, we found the RNA recognition motif (RRM) containing DNAJC17 to be pan-essential and investigated the contribution of its structural domains to biochemical and cellular function. We found that the RRM exerts an auto-inhibitory effect on the ability of DNAJC17 to allosterically activate ATP hydrolysis by HSP70. The J-domain, but neither the RRM nor a distal C-terminal alpha helix are required to rescue cell viability after loss of endogenous DNAJC17 . Knockdown of DNAJC17 leads to relatively few conserved changes in the abundance of individual mRNAs, but instead deranges gene expression through exon skipping, primarily of genes involved in cell cycle progression. Concordant with cell viability experiments, the C-terminal portions of DNAJC17 are dispensable for restoring splicing and G2-M progression. Overall, our findings identify essential cellular JDPs and suggest that diversification in JDP structure extends the HSP70-JDP system to control divergent processes such as RNA splicing. Future investigations into the structural basis for auto-inhibition of the DNAJC17 J-domain and the molecular regulation of splicing by these components may provide insights on how conserved biochemical mechanisms can be programmed to fill unique, non-redundant cellular roles and broaden the scope of the proteostasis network.

FET fusion oncoproteins disrupt physiologic DNA repair networks and induce ATR synthetic lethality in cancer.

The genetic principle of synthetic lethality is clinically validated in cancers with loss of specific DNA damage response (DDR) pathway genes (i.e. BRCA1/2 tumor suppressor mutations). The broader question of whether and how oncogenes create tumor-specific vulnerabilities within DDR networks remains unanswered. Native FET protein family members are among the earliest proteins recruited to DNA double-strand breaks (DSBs) during the DDR, though the function of both native FET proteins and FET fusion oncoproteins in DSB repair remains poorly defined. Here we focus on Ewing sarcoma (ES), an EWS-FLI1 fusion oncoprotein-driven pediatric bone tumor, as a model for FET rearranged cancers. We discover that the EWS-FLI1 fusion oncoprotein is recruited to DNA DSBs and interferes with native EWS function in activating the DNA damage sensor ATM. Using preclinical mechanistic approaches and clinical datasets, we establish functional ATM deficiency as a principal DNA repair defect in ES and the compensatory ATR signaling axis as a collateral dependency and therapeutic target in FET rearranged cancers. Thus, aberrant recruitment of a fusion oncoprotein to sites of DNA damage can disrupt normal DSB repair, revealing a mechanism for how oncogenes can create cancer-specific synthetic lethality within DDR networks.

Long Non-Coding RNAs as Emerging Targets in Lung Cancer.

Long non-coding RNAs (LncRNAs) are mRNA-like molecules that do not encode for proteins and that are longer than 200 nucleotides. LncRNAs play important biological roles in normal cell physiology and organism development. Therefore, deregulation of their activities is involved in disease processes such as cancer. Lung cancer is the leading cause of cancer-related deaths due to late stage at diagnosis, distant metastasis, and high rates of therapeutic failure. LncRNAs are emerging as important molecules in lung cancer for their oncogenic or tumor-suppressive functions. LncRNAs are highly stable in circulation, presenting an opportunity for use as non-invasive and early-stage cancer diagnostic tools. Here, we summarize the latest works providing in vivo evidence available for lncRNAs role in cancer development, therapy-induced resistance, and their potential as biomarkers for diagnosis and prognosis, with a focus on lung cancer. Additionally, we discuss current therapeutic approaches to target lncRNAs. The evidence discussed here strongly suggests that investigation of lncRNAs in lung cancer in addition to protein-coding genes will provide a holistic view of molecular mechanisms of cancer initiation, development, and progression, and could open up a new avenue for cancer treatment.

3-Phosphoinositide-dependent kinase 1 drives acquired resistance to osimertinib.

Osimertinib sensitive and resistant NSCLC NCI-H1975 clones are used to model osimertinib acquired resistance in humanized and non-humanized mice and delineate potential resistance mechanisms. No new EGFR mutations or loss of the EGFR T790M mutation are found in resistant clones. Resistant tumors grown under continuous osimertinib pressure both in humanized and non-humanized mice show aggressive tumor regrowth which is significantly less sensitive to osimertinib as compared with parental tumors. 3-phosphoinositide-dependent kinase 1 (PDK1) is identified as a potential driver of osimertinib acquired resistance, and its selective inhibition by BX795 and CRISPR gene knock out, sensitizes resistant clones. In-vivo inhibition of PDK1 enhances the osimertinib sensitivity against osimertinib resistant xenograft and a patient derived xenograft (PDX) tumors. PDK1 knock-out dysregulates PI3K/Akt/mTOR signaling, promotes cell cycle arrest at the G1 phase. Yes-associated protein (YAP) and active-YAP are upregulated in resistant tumors, and PDK1 knock-out inhibits nuclear translocation of YAP. Higher expression of PDK1 and an association between PDK1 and YAP are found in patients with progressive disease following osimertinib treatment. PDK1 is a central upstream regulator of two critical drug resistance pathways: PI3K/AKT/mTOR and YAP.

FET fusion oncoproteins disrupt physiologic DNA repair networks in cancer.

While oncogenes promote cancer cell growth, unrestrained proliferation represents a significant stressor to cellular homeostasis networks such as the DNA damage response (DDR). To enable oncogene tolerance, many cancers disable tumor suppressive DDR signaling through genetic loss of DDR pathways and downstream effectors (e.g., ATM or p53 tumor suppressor mutations). Whether and how oncogenes can help "self-tolerize" by creating analogous functional deficiencies in physiologic DDR networks is not known. Here we focus on Ewing sarcoma, a FET fusion oncoprotein (EWS-FLI1) driven pediatric bone tumor, as a model for the class of FET rearranged cancers. Native FET protein family members are among the earliest factors recruited to DNA double-strand breaks (DSBs) during the DDR, though the function of both native FET proteins and FET fusion oncoproteins in DNA repair remains to be defined. Using preclinical mechanistic studies of the DDR and clinical genomic datasets from patient tumors, we discover that the EWS-FLI1 fusion oncoprotein is recruited to DNA DSBs and interferes with native FET (EWS) protein function in activating the DNA damage sensor ATM. As a consequence of FET fusion-mediated interference with the DDR, we establish functional ATM deficiency as the principal DNA repair defect in Ewing sarcoma and the compensatory ATR signaling axis as a collateral dependency and therapeutic target in multiple FET rearranged cancers. More generally, we find that aberrant recruitment of a fusion oncoprotein to sites of DNA damage can disrupt physiologic DSB repair, revealing a mechanism for how growth-promoting oncogenes can also create a functional deficiency within tumor suppressive DDR networks.

Phase 1 Study of Ceritinib Combined With Trametinib in Patients With Advanced ALK- or ROS1-Positive NSCLC.

Introduction: In patients with NSCLC harboring oncogenic ALK or ROS1 rearrangements, tyrosine kinase inhibitors have yielded high response rates and improvements in progression-free survival compared with cytotoxic chemotherapy; however, acquired resistance eventually develops. In preclinical models, ALK and MEK coinhibition was able to overcome ALK inhibitor resistance. Methods: A phase 1 study of the ALK/ROS1 inhibitor ceritinib and the MEK inhibitor trametinib in patients with refractory NSCLC harboring ALK or ROS1 fusions was initiated. A three plus three dose-escalation scheme was used. Two dose levels were investigated. The primary end point was to determine the safety and tolerability of the combination. Results: Nine patients (n = 8 ALK+, n = 1 ROS1+) were enrolled in the study and completed at least one cycle of therapy. The most common adverse events (all grades) were diarrhea (n = 9; 100%), rash (n = 8; 89%), abdominal pain (n = 5; 56%), and elevated aspartate transaminase/alanine transaminase level (n = 4; 44%). The overall response rate was 22%, whereas disease control rate was 56%. Median duration of response was 7.85 months. The median progression-free survival was 3.0 months (95% confidence interval: 1.5-7.0 mo). The median overall survival was 8.9 months (95% confidence interval: 2.0-not reached). Conclusions: Data from this trial indicate that the combination of ceritinib and trametinib had no unexpected toxicities and that a tolerable dose could be identified. A subset of patients seemed to obtain clinical benefit from this treatment after progression on prior ALK/ROS1 inhibitor treatment.ClinicalTrials.gov Identifier: NCT03087448.

Quantitative Framework for Bench-to-Bedside Cancer Research.

Bioscience is an interdisciplinary venture. Driven by a quantum shift in the volume of high throughput data and in ready availability of data-intensive technologies, mathematical and quantitative approaches have become increasingly common in bioscience. For instance, a recent shift towards a quantitative description of cells and phenotypes, which is supplanting conventional qualitative descriptions, has generated immense promise and opportunities in the field of bench-to-bedside cancer OMICS, chemical biology and pharmacology. Nevertheless, like any burgeoning field, there remains a lack of shared and standardized framework for quantitative cancer research. Here, in the context of cancer, we present a basic framework and guidelines for bench-to-bedside quantitative research and therapy. We outline some of the basic concepts and their parallel use cases for chemical-protein interactions. Along with several recommendations for assay setup and conditions, we also catalog applications of these quantitative techniques in some of the most widespread discovery pipeline and analytical methods in the field. We believe adherence to these guidelines will improve experimental design, reduce variabilities and standardize quantitative datasets.

GATOR2-dependent mTORC1 activity is a therapeutic vulnerability in FOXO1 fusion-positive rhabdomyosarcoma.

Oncogenic FOXO1 gene fusions drive a subset of rhabdomyosarcoma (RMS) with poor survival; to date, these cancer drivers are therapeutically intractable. To identify new therapies for this disease, we undertook an isogenic CRISPR-interference screen to define PAX3-FOXO1-specific genetic dependencies and identified genes in the GATOR2 complex. GATOR2 loss in RMS abrogated aa-induced lysosomal localization of mTORC1 and consequent downstream signaling, slowing G1-S cell cycle transition. In vivo suppression of GATOR2 impaired the growth of tumor xenografts and favored the outgrowth of cells lacking PAX3-FOXO1. Loss of a subset of GATOR2 members can be compensated by direct genetic activation of mTORC1. RAS mutations are also sufficient to decouple mTORC1 activation from GATOR2, and indeed, fusion-negative RMS harboring such mutations exhibit aa-independent mTORC1 activity. A bisteric, mTORC1-selective small molecule induced tumor regressions in fusion-positive patient-derived tumor xenografts. These findings highlight a vulnerability in FOXO1 fusion-positive RMS and provide rationale for the clinical evaluation of bisteric mTORC1 inhibitors, currently in phase I testing, to treat this disease. Isogenic genetic screens can, thus, identify potentially exploitable vulnerabilities in fusion-driven pediatric cancers that otherwise remain mostly undruggable.

Primary and metastatic tumors exhibit systems-level differences in dependence on mitochondrial respiratory function.

The Warburg effect, aerobic glycolysis, is a hallmark feature of cancer cells grown in culture. However, the relative roles of glycolysis and respiratory metabolism in supporting in vivo tumor growth and processes such as tumor dissemination and metastatic growth remain poorly understood, particularly on a systems level. Using a CRISPRi mini-library enriched for mitochondrial ribosomal protein and respiratory chain genes in multiple human lung cancer cell lines, we analyzed in vivo metabolic requirements in xenograft tumors grown in distinct anatomic contexts. While knockdown of mitochondrial ribosomal protein and respiratory chain genes (mito-respiratory genes) has little impact on growth in vitro, tumor cells depend heavily on these genes when grown in vivo as either flank or primary orthotopic lung tumor xenografts. In contrast, respiratory function is comparatively dispensable for metastatic tumor growth. RNA-Seq and metabolomics analysis of tumor cells expressing individual sgRNAs against mito-respiratory genes indicate overexpression of glycolytic genes and increased sensitivity of glycolytic inhibition compared to control when grown in vitro, but when grown in vivo as primary tumors these cells down-regulate glycolytic mechanisms. These studies demonstrate that discrete perturbations of mitochondrial respiratory chain function impact in vivo tumor growth in a context-specific manner with differential impacts on primary and metastatic tumors.

AXL and Error-Prone DNA Replication Confer Drug Resistance and Offer Strategies to Treat EGFR-Mutant Lung Cancer.

Anticancer therapies have been limited by the emergence of mutations and other adaptations. In bacteria, antibiotics activate the SOS response, which mobilizes error-prone factors that allow for continuous replication at the cost of mutagenesis. We investigated whether the treatment of lung cancer with EGFR inhibitors (EGFRi) similarly engages hypermutators. In cycling drug-tolerant persister (DTP) cells and in EGFRi-treated patients presenting residual disease, we observed upregulation of GAS6, whereas ablation of GAS6's receptor, AXL, eradicated resistance. Reciprocally, AXL overexpression enhanced DTP survival and accelerated the emergence of T790M, an EGFR mutation typical to resistant cells. Mechanistically, AXL induces low-fidelity DNA polymerases and activates their organizer, RAD18, by promoting neddylation. Metabolomics uncovered another hypermutator, AXL-driven activation of MYC, and increased purine synthesis that is unbalanced by pyrimidines. Aligning anti-AXL combination treatments with the transition from DTPs to resistant cells cured patient-derived xenografts. Hence, similar to bacteria, tumors tolerate therapy by engaging pharmacologically targetable endogenous mutators. SIGNIFICANCE: EGFR-mutant lung cancers treated with kinase inhibitors often evolve resistance due to secondary mutations. We report that in similarity to the bacterial SOS response stimulated by antibiotics, endogenous mutators are activated in drug-treated cells, and this heralds tolerance. Blocking the process prevented resistance in xenograft models, which offers new treatment strategies. This article is highlighted in the In This Issue feature, p. 2483.

Deficiency of the splicing factor RBM10 limits EGFR inhibitor response in EGFR-mutant lung cancer.

Molecularly targeted cancer therapy has improved outcomes for patients with cancer with targetable oncoproteins, such as mutant EGFR in lung cancer. Yet, the long-term survival of these patients remains limited, because treatment responses are typically incomplete. One potential explanation for the lack of complete and durable responses is that oncogene-driven cancers with activating mutations of EGFR often harbor additional co-occurring genetic alterations. This hypothesis remains untested for most genetic alterations that co-occur with mutant EGFR. Here, we report the functional impact of inactivating genetic alterations of the mRNA splicing factor RNA-binding motif 10 (RBM10) that co-occur with mutant EGFR. RBM10 deficiency decreased EGFR inhibitor efficacy in patient-derived EGFR-mutant tumor models. RBM10 modulated mRNA alternative splicing of the mitochondrial apoptotic regulator Bcl-x to regulate tumor cell apoptosis during treatment. Genetic inactivation of RBM10 diminished EGFR inhibitor-mediated apoptosis by decreasing the ratio of (proapoptotic) Bcl-xS to (antiapoptotic) Bcl-xL isoforms of Bcl-x. RBM10 deficiency was a biomarker of poor response to EGFR inhibitor treatment in clinical samples. Coinhibition of Bcl-xL and mutant EGFR overcame the resistance induced by RBM10 deficiency. This study sheds light on the role of co-occurring genetic alterations and on the effect of splicing factor deficiency on the modulation of sensitivity to targeted kinase inhibitor cancer therapy.