Hypoxia Promotes the Stemness of Mesangiogenic Progenitor Cells and Prevents Osteogenic but not Angiogenic Differentiation.

The stem cell niche in the bone marrow is a hypoxic environment, where the low oxygen tension preserves the pluripotency of stem cells. We have identified mesangiogenic progenitor cells (MPC) exhibiting angiogenic and mesenchymal differentiation capabilities in vitro. The effect of hypoxia on MPC has not been previously explored. In this study, MPCs were isolated from volunteers' bone marrow and cultured under both normoxic and hypoxic conditions (3% O2). MPCs maintained their characteristic morphology and surface marker expression (CD18 + CD31 + CD90-CD73-) under hypoxia. However, hypoxic conditions led to reduced MPC proliferation in primary cultures and hindered their differentiation into mesenchymal stem cells (MSCs) upon exposure to differentiative medium. First passage MSCs derived from MPC appeared unaffected by hypoxia, exhibiting no discernible differences in proliferative potential or cell cycle. However, hypoxia impeded the subsequent osteogenic differentiation of MSCs, as evidenced by decreased hydroxyapatite deposition. Conversely, hypoxia did not impact the angiogenic differentiation potential of MPCs, as demonstrated by spheroid-based assays revealing comparable angiogenic sprouting and tube-like formation capabilities under both hypoxic and normoxic conditions. These findings indicate that hypoxia preserves the stemness phenotype of MPCs, inhibits their differentiation into MSCs, and hampers their osteogenic maturation while leaving their angiogenic potential unaffected. Our study sheds light on the intricate effects of hypoxia on bone marrow-derived MPCs and their differentiation pathways.

Dabrafenib-trametinib in BRAF V600-mutated non-small-cell lung cancer: a single center real world experience.

Aim: We retrospectively evaluated the effect of dabrafenib/trametinib combination in patients with BRAF-mutated non-small-cell lung cancer (NSCLC) treated in a single center from 2017 to 2022. Patients: The response and safety data of 42 patients (27 treated in first-line and 15 as second/subsequent lines) were analyzed. Results: The objective response was 73.8%, with no differences between patients undergoing first- or second-line. A longer, statistically significant median progression-free survival (PFS) was observed in patients receiving the combination in first-line vs those in the second/subsequent lines (19.9 months [95% CI: 19.7-20] vs 13.1 months [95% CI: 8.6-17.6], respectively; p = 0.012). The median overall survival (OS) was 29.9 months (95% CI: 14.1-45.7) for patients treated with the combination in first-line and 22.4 months (95% CI: 14.6-30.2) for those treated in subsequent lines. The combination was well tolerated. Conclusion: We confirm the efficacy of dabrafenib/trametinib in BRAF-V600-mutated NSCLC.

[Box: see text].

Cardiovascular Toxicity of Antineoplastic Treatments in Hematological Diseases: Focus on Molecular Mechanisms to Improve Therapeutic Management.

In recent years, advancements in the treatment of hematologic neoplasms have led to more effective and less toxic therapeutic schemes, resulting in prolonged patient life expectancy. However, the success of these treatments has also brought about an increased prevalence of cardiovascular adverse events, becoming a significant concern for the growing population of cancer survivors. Antineoplastic therapies, targeting both tumor and organ vessels, contribute to vascular toxicity, influenced by genetic factors and pre-existing vascular diseases. Chemotherapeutic agents and targeted treatments can induce cardiovascular toxicity by affecting endothelial cells and cardiomyocytes through various mechanisms, including hypoxia, vasculature abnormalities, and direct effects on cardiomyocytes. Cardiovascular adverse events encompass a wide range, from cardiac dysfunction to an elevated risk of arrhythmias. While early cardiac events are well-described in clinical trials, delayed toxicities are gaining relevance due to prolonged patient survival. The review focuses on the cardiac and vascular toxicity of antineoplastic drugs in hematological disorders, providing insights into the molecular physiopathology of cancer therapy-associated cardiotoxicity. Understanding how these drugs interact with the heart and blood vessels is essential for predicting, detecting, and managing chemotherapy-related heart issues.

Clinical utility of Next Generation Sequencing of plasma cell-free DNA for the molecular profiling of patients with NSCLC at diagnosis and disease progression.

BACKGROUND: The present study evaluates the utility of NGS analysis of circulating free DNA (cfDNA), which incorporates small amounts of tumor DNA (ctDNA), at diagnosis or at disease progression (PD) in NSCLC patients. METHODS: Comprehensive genomic profiling on cfDNA by NGS were performed in NSCLC patients at diagnosis (if tissue was unavailable/insufficient) or at PD to investigate potential druggable molecular aberrations. Blood samples were collected as routinary diagnostic procedures, DNA was extracted, and the NextSeq 550 Illumina platform was used to run the Roche Avenio ctDNA Expanded Kit for molecular analyses. Gene variants were classified accordingly to the ESCAT score. RESULTS: A total of 106 patients were included in this study; 44 % of cases were requested because of tissue unavailability at the diagnosis and 56 % were requested at the PD. At least one driver alteration was observed in 62 % of cases at diagnosis. Driver druggable variants classified as ESCAT level I were detected in 34 % of patients, including ALK-EML4, ROS1-CD74, EGFR, BRAF, KRAS p.G12C, PI3KCA. In the PD group, most patients were EGFR-positive, progressing to a first line-therapy. Sixty-three percent of patients had at least one driver alteration detected in blood and 17 % of patients had a known biological mechanism of resistance allowing further therapeutic decisions. CONCLUSIONS: The present study confirms the potential of liquid biopsy to detect tumour molecular heterogeneity in NSCLC patients at the diagnosis and at PD, demonstrating that a significant number of druggable mutations and mechanisms of resistance can be detected by NGS analysis on ctDNA.

Clinical evidence and adverse event management update of patients with RET- rearranged advanced non-small-cell lung cancer (NSCLC) treated with pralsetinib.

Current non-small cell lung cancer (NSCLC) management relies on genome-driven precision oncology thus shifting treatment paradigm towards biomarker-guided tumor-agnostic approaches. Recently, rearranged during transfection (RET) has been endorsed as tissue-agnostic target with sensitivity to RET inhibition. There are currently two selective RET tyrosine kinase inhibitors, pralsetinib and selpercatinib. The recent introduction of pralsetinib in the treatment algorithm of RET-rearranged tumor along with the mounting clinical evidence of pralsetinib durable activity from both randomized and observational studies holds the potential to disclose new avenues in the management of RET fusion positive NSCLC patients. Our narrative review aims to discuss the available clinical evidence on pralsetinib efficacy, particularly on brain metastases, and tolerability profile. In addition, our work explores the relevance of detecting RET fusions upfront in the disease history of patients with NSCLC.

Somatic mutations of thymic epithelial tumors with myasthenia gravis.

Background: Thymic epithelial tumors are rare malignant neoplasms that are frequently associated with paraneoplastic syndromes, especially myasthenia gravis. GTF2I is an oncogene mutated in a subgroup of thymomas that is reputed to drive their growth. However, for GTF2I wild-type tumors, the relevant mutations remain to be identified. Methods: We performed a meta-analysis and identified 4,208 mutations in 339 patients. We defined a panel of 63 genes frequently mutated in thymic epithelial tumors, which we used to design a custom assay for next-generation sequencing. We sequenced tumor DNA from 67 thymomas of patients with myasthenia gravis who underwent resection in our institution. Results: Among the 67 thymomas, there were 238 mutations, 83 of which were in coding sequences. There were 14 GTF2I mutations in 6 A, 5 AB, 2 B2 thymomas, and one in a thymoma with unspecified histology. No other oncogenes showed recurrent mutations, while sixteen tumor suppressor genes were predicted to be inactivated. Even with a dedicated assay for the identification of specific somatic mutations in thymic epithelial tumors, only GTF2I mutations were found to be significantly recurrent. Conclusion: Our evaluation provides insights into the mutational landscape of thymic epithelial tumors, identifies recurrent mutations in different histotypes, and describes the design and implementation of a custom panel for targeted resequencing. These findings contribute to a better understanding of the genetic basis of thymic epithelial tumors and may have implications for future research and treatment strategies.

Gene-network analysis predicts clinical response to immunotherapy in patients affected by NSCLC.

OBJECTIVES: Predictive biomarkers of response to immune checkpoint inhibitors (ICIs) have been extensively studied in non-small cell lung cancer (NSCLC) with controversial results. Recently, gene-network analysis emerged as a new tool to address tumor biology and behavior, representing a potential tool to evaluate response to therapies. METHODS: Clinical data and genetic profiles of 644 advanced NSCLCs were retrieved from cBioPortal and the Cancer Genome Atlas (TCGA); 243 ICI-treated NSCLCs were used to identify an immunotherapy response signatures via mutated gene network analysis and K-means unsupervised clustering. Signatures predictive values were tested in an external dataset of 242 cases and assessed versus a control group of 159 NSCLCs treated with standard chemotherapy. RESULTS: At least two mutations in the coding sequence of genes belonging to the chromatin remodelling pathway (A signature), and/or at least two mutations of genes involved in cell-to-cell signalling pathways (B signature), showed positive prediction in ICI-treated advanced NSCLC. Signatures performed best when combined for patients undergoing first-line immunotherapy, and for those receiving combined ICIs. CONCLUSIONS: Alterations in genes related to chromatin remodelling complexes and cell-to-cell crosstalk may force dysfunctional immune evasion, explaining susceptibility to immunotherapy. Therefore, exploring mutated gene networks could be valuable for determining essential biological interactions, contributing to treatment personalization.

Mesenchymal Stem Cell in Pancreatic Islet Transplantation.

Pancreatic islet transplantation is a therapeutic option for achieving physiologic regulation of plasma glucose in Type 1 diabetic patients. At the same time, mesenchymal stem cells (MSCs) have demonstrated their potential in controlling graft rejection, the most fearsome complication in organ/tissue transplantation. MSCs can interact with innate and adaptive immune system cells either through direct cell-cell contact or through their secretome including exosomes. In this review, we discuss current findings regarding the graft microenvironment of pancreatic islet recipient patients and the crucial role of MSCs operation as cell managers able to control the immune system to prevent rejection and promote endogenous repair. We also discuss how challenging stressors, such as oxidative stress and impaired vasculogenesis, may jeopardize graft outcomes. In order to face these adverse conditions, we consider either hypoxia-exposure preconditioning of MSCs or human stem cells with angiogenic potential in organoids to overcome islets' lack of vasculature. Along with the shepherding of carbon nanotubes-loaded MSCs to the transplantation site by a magnetic field, these studies look forward to exploiting MSCs stemness and their immunomodulatory properties in pancreatic islet transplantation.

STYLE (NCT03449173): A Phase 2 Trial of Sunitinib in Patients With Type B3 Thymoma or Thymic Carcinoma in Second and Further Lines.

INTRODUCTION: Thymic malignancies are rare tumors with few therapeutic options. The STYLE trial was aimed to evaluate activity and safety of sunitinib in advanced or recurrent type B3 thymoma (T) and thymic carcinoma (TC). METHODS: In this multicenter, Simon 2 stages, phase 2 trial, patients with pretreated T or TC were enrolled in two cohorts and assessed separately. Sunitinib was administered 50 mg daily for 4 weeks, followed by a 2-week rest period (schedule 4/2), until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR). Progression-free survival, overall survival, disease control rate and safety were secondary endpoints. RESULTS: From March 2017 to January 2022, 12 patients with T and 32 patients with TC were enrolled. At stage 1, ORR was 0% (90% confidence interval [CI]: 0.0-22.1) in T and 16.7% (90% CI: 3.1-43.8) in TC, so the T cohort was closed. At stage 2, the primary endpoint was met for TC with ORR of 21.7% (90% CI: 9.0%-40.4%). In the intention-to-treat analysis, disease control rate was 91.7% (95% CI: 61.5%-99.8%) in Ts and 89.3% (95% CI: 71.8%-97.7%) in TCs. Median progression-free survival was 7.7 months (95% CI: 2.4-45.5) in Ts and 8.8 months (95% CI: 5.3-11.1) in TCs; median overall survival was 47.9 months (95% CI: 4.5-not reached) in Ts and 27.8 months (95% CI: 13.2-53.2) in TCs. Adverse events occurred in 91.7% Ts and 93.5% TCs. Grade 3 or greater treatment-related adverse events were reported in 25.0% Ts and 51.6% TCs. CONCLUSIONS: This trial confirms the activity of sunitinib in patients with TC, supporting its use as a second-line treatment, albeit with potential toxicity that requires dose adjustment.

Comparison of digital PCR systems for the analysis of liquid biopsy samples of patients affected by lung and colorectal cancer.

BACKGROUND AND AIMS: Highly sensitive technologies are available for the molecular characterization of solid tumors, including digital PCR (dPCR). Liquid biopsy, based on the analysis of cell-free DNA (cfDNA), is often used to assess EGFR or RAS alterations in lung and colorectal cancers. Our study aimed to compare the results of two different dPCR platforms for the detection of mutations in cfDNA. METHODS: Plasma samples from lung and colorectal cancer patients collected as per routine procedures have been tested. cfDNA Was extracted from plasma, and samples were screened on the droplet digital PCR (ddPCR, BioRad) and solid dPCR QIAcuity (Qiagen). RESULTS: A total of 42 samples were analyzed, obtained from 20 Non-Small Cell Lung Cancer (NSCLC) patients carrying an EGFR or a KRAS mutation on tissue at diagnosis, and from 22 samples of colorectal cancer (CRC) patients, 10 of which presenting a KRAS mutation. EGFR mutation detection was 58.8% for ddPCR and 100% for dPCR (κ = 0.54; 95% CI, 0.37-0.71), compared to tissue results. The detection rate for RAS mutations was 72.7% for ddPCR and 86.4% for dPCR (κ = 0.34; 95% CI, 0.01-0.68), compared to tissue results. CONCLUSIONS: This study showed moderate agreement between dPCR and ddPCR. Sampling effect or threshold settings may potentially explain the differences in the cfDNA data between the two different platforms.

Molecular and Functional Key Features and Oncogenic Drivers in Thymic Carcinomas.

Thymic epithelial tumors, comprising thymic carcinomas and thymomas, are rare neoplasms. They differ in histology, prognosis, and association with autoimmune diseases such as myasthenia gravis. Thymomas, but not thymic carcinomas, often harbor GTF2I mutations. Mutations of CDKN2A, TP53, and CDKN2B are the most common thymic carcinomas. The acquisition of mutations in genes that control chromatin modifications and epigenetic regulation occurs in the advanced stages of thymic carcinomas. Anti-angiogenic drugs and immune checkpoint inhibitors targeting the PD-1/PD-L1 axis have shown promising results for the treatment of unresectable tumors. Since thymic carcinomas are frankly aggressive tumors, this report presents insights into their oncogenic drivers, categorized under the established hallmarks of cancer.

Isolation and characterization of two newly established thymoma PDXs from two relapses of the same patient: a new tool to investigate thymic malignancies.

BACKGROUND: Thymic malignancies are a heterogeneous group of rare cancers for which systemic chemotherapy is the standard treatment in the setting of advanced, recurrent or refractory diseases. Both environmental and genetic risk factors have not been fully clarified and few target-specific drugs have been developed for thymic epithelial tumors. A major challenge in studying thymic epithelial tumors is the lack of preclinical models for translational studies. MAIN BODY: Starting from bioptic material of two consecutive recurrences of the same patient, we generated two patient-derived xenografts. The patient-derived xenografts models were characterized for histology by immunohistochemistry and mutations using next-generation sequencing. When compared to the original tumors resected from the patient, the two patient-derived xenografts had preserved morphology after the stain with hematoxylin and eosin, although there was a moderate degree of de-differentiation. From a molecular point of view, the two patient-derived xenografts maintained 74.3 and 61.8% of the mutations present in the human tumor of origin. SHORT CONCLUSION: The newly generated patient-derived xenografts recapitulate both the molecular characteristics and the evolution of the thymoma it derives from well, allowing to address open questions for this rare cancer.

Pulmonary cancers across different histotypes share hybrid tuft cell/ionocyte-like molecular features and potentially druggable vulnerabilities.

Tuft cells are chemosensory epithelial cells in the respiratory tract and several other organs. Recent studies revealed tuft cell-like gene expression signatures in some pulmonary adenocarcinomas, squamous cell carcinomas (SQCC), small cell carcinomas (SCLC), and large cell neuroendocrine carcinomas (LCNEC). Identification of their similarities could inform shared druggable vulnerabilities. Clinicopathological features of tuft cell-like (tcl) subsets in various lung cancer histotypes were studied in two independent tumor cohorts using immunohistochemistry (n = 674 and 70). Findings were confirmed, and additional characteristics were explored using public datasets (RNA seq and immunohistochemical data) (n = 555). Drug susceptibilities of tuft cell-like SCLC cell lines were also investigated. By immunohistochemistry, 10-20% of SCLC and LCNEC, and approximately 2% of SQCC expressed POU2F3, the master regulator of tuft cells. These tuft cell-like tumors exhibited "lineage ambiguity" as they co-expressed NCAM1, a marker for neuroendocrine differentiation, and KRT5, a marker for squamous differentiation. In addition, tuft cell-like tumors co-expressed BCL2 and KIT, and tuft cell-like SCLC and LCNEC, but not SQCC, also highly expressed MYC. Data from public datasets confirmed these features and revealed that tuft cell-like SCLC and LCNEC co-clustered on hierarchical clustering. Furthermore, only tuft cell-like subsets among pulmonary cancers significantly expressed FOXI1, the master regulator of ionocytes, suggesting their bidirectional but immature differentiation status. Clinically, tuft cell-like SCLC and LCNEC had a similar prognosis. Experimentally, tuft cell-like SCLC cell lines were susceptible to PARP and BCL2 co-inhibition, indicating synergistic effects. Taken together, pulmonary tuft cell-like cancers maintain histotype-related clinicopathologic characteristics despite overlapping unique molecular features. From a therapeutic perspective, identification of tuft cell-like LCNECs might be crucial given their close kinship with tuft cell-like SCLC.

Amivantamab in the Treatment of Metastatic NSCLC: Patient Selection and Special Considerations.

Amivantamab is a bispecific antibody that recognizes epidermal growth factor receptor (EGFR) and MET proto-oncogene (MET). In May 2021, the Food and Drug Administration gave an accelerated approval of amivantamab for the treatment of non-small cell lung cancer (NSCLC) patients with EGFR exon 20 insertions (Exon20ins) who progressed after platinum-based chemotherapy. Amivantamab prevents ligand binding to EGFR and MET and the dimerization of the receptors suppressing the downstream signal transduction. Moreover, amivantamab determines antibody dependent cellular cytotoxicity and down regulation of cell surface proteins through internalization of the receptor and trogocytosis. Preliminary results of the Phase I/IB CHRYSALIS trial demonstrated an objective response rate of 40% with a median duration of response of 11.1 months (95% CI 9.6-not reached) in 81 patients treated with amivantamab with pretreated NSCLC with Exon20ins EGFR mutations. In a different cohort of the CHRYSALIS trial, patients with Ex19del and L858R EGFR mutations were enrolled after progression on osimertinib. 121 and 45 patients received amivantamab or a combination with lazertinib, a third-generation tyrosine kinase inhibitor, respectively. The objective response rate was 19% and 36% in patients treated with amivantamab alone or in combination with lazertinib, with a median progression-free survival of 6.9 (95% CI: 3.2-5.3) and 11.1 (95% CI: 3.7-9.5) months, respectively. All 20 patients with Ex19del and L858R EGFR mutations who received amivantamab and lazertinib as their first line treatment achieved an objective response. Amivantamab is currently under evaluation in Phase III clinical trials for the first line treatment of NSCLCs with Exon20ins EGFR mutations in combination with chemotherapy (PAPILLON), for the first line therapy of Ex19del and L858R mutated NSCLCs in combination with lazertinib (MARIPOSA) and in combination with chemotherapy and lazertinib in NSCLCs who progressed on osimertinib (MARIPOSA-2).

Detecting cell-of-origin and cancer-specific methylation features of cell-free DNA from Nanopore sequencing.

The Oxford Nanopore (ONT) platform provides portable and rapid genome sequencing, and its ability to natively profile DNA methylation without complex sample processing is attractive for point-of-care real-time sequencing. We recently demonstrated ONT shallow whole-genome sequencing to detect copy number alterations (CNAs) from the circulating tumor DNA (ctDNA) of cancer patients. Here, we show that cell type and cancer-specific methylation changes can also be detected, as well as cancer-associated fragmentation signatures. This feasibility study suggests that ONT shallow WGS could be a powerful tool for liquid biopsy.

ED-B-Containing Isoform of Fibronectin in Tumor Microenvironment of Thymomas: A Target for a Theragnostic Approach.

AIM: to exploit tissue-specific interactions among thymic epithelial tumor (TETs) cells and extra-domain B fibronectin (ED-B FN). MATERIAL AND METHODS: The stromal pattern of ED-B FN expression was investigated through tumor specimen collection and molecular profiling in 11 patients with recurrent TETs enrolled in prospective theragnostic phase I/II trials with Radretumab, an ED-B FN specific recombinant human antibody. Radretumab radioimmunotherapy (R-RIT) was offered to patients who exhibited the target expression. Experiments included immunochemical analysis (ICH), cell cultures, immunophenotypic analysis, Western blot, slot-blot assay, and quantitative RT-PCR of two primary thymoma cultures we obtained from patients' samples and in the Ty82 cell line. RESULTS: The in vivo scintigraphic demonstration of ED-B FN expression resulted in R-RIT eligibility in 8/11 patients, of which seven were treated. The best observed response was disease stabilization (n = 5/7) with a duration of 4.3 months (range 3-5 months). IHC data confirmed high ED-B FN expression in the peripherical microenvironment rather than in the center of the tumor, which was more abundant in B3 thymomas. Further, there was a predominant expression of ED-B FN by the stromal cells of the thymoma microenvironment rather than the epithelial cells. CONCLUSIONS: Our data support the hypothesis that thymomas induce stromal cells to shift FN production to the ED-B subtype, likely representing a favorable hallmark for tumor progression and metastasis. Collectively, results derived from clinical experience and molecular insights of the in vitro experiments suggested that R-RIT inefficacy is unlikely related to low target expression in TET, being the mechanism of R-RIT resistance eventually related to patients' susceptibility (i.e., inherent characteristics), the pattern expression of the target (i.e., at periphery), the biological characteristics of the tumor (i.e., aggressive and resistant phenotypes), and/or to format of the target agent (i.e., 131I-L19-SIP).

Defining TCRγδ lymphoproliferative disorders by combined immunophenotypic and molecular evaluation.

Tγδ large granular lymphocyte leukemia (Tγδ LGLL) is a rare lymphoproliferative disease, scantily described in literature. A deep-analysis, in an initial cohort of 9 Tγδ LGLL compared to 23 healthy controls, shows that Tγδ LGLL dominant clonotypes are mainly public and exhibit different V-(D)-J γ/δ usage between patients with symptomatic and indolent Tγδ neoplasm. Moreover, some clonotypes share the same rearranged sequence. Data obtained in an enlarged cohort (n = 36) indicate the importance of a combined evaluation of immunophenotype and STAT mutational profile for the correct management of patients with Tγδ cell expansions. In fact, we observe an association between Vδ2/Vγ9 clonality and indolent course, while Vδ2/Vγ9 negativity correlates with symptomatic disease. Moreover, the 7 patients with STAT3 mutations have neutropenia and a CD56-/Vδ2- phenotype, and the 3 cases with STAT5B mutations display an asymptomatic clinical course and CD56/Vδ2 expression. All these data indicate that biological characterization is needed for Tγδ-cell neoplasm definition.

Gene network Analysis Defines a Subgroup of Small Cell Lung Cancer patients With Short Survival.

BACKGROUND: Small cell lung cancer (SCLC) is an aggressive tumor, and despite its sensitivity to chemotherapy and radiotherapy, patients usually have a short survival. There are no clinically relevant predictive factors of responses to therapies, and therapeutic options are still limited. MATERIALS AND METHODS: Clinical data and somatic mutations of genes included in the MSK-IMPACT panel were retrieved from cBioPortal for 108 SCLCs and analyzed to identify mutated gene networks. Results were validated in an independent cohort of 54 SCLCs, whose information was also available from cBioPortal. RESULTS: Different networks were observed in tumors of short and long survivors. Degree (K) and betweenness (B) are key features that characterize a gene in its network of related mutations. By comparing their B/K ratio, 2 signatures of mutated genes were identified, describing short (IL-7R, NTRK2, HNF-1A) and long survivors (NBN, PTPN-11, IRS-1, INPP-4A, PIK-3CG, HGF, LATS-2, SMARCA-4, FLT-3, EIF-4A2, SPEN, PAX-5, SH2-D1A, ARID-1A, HOXB-13, ERCC-4, FANCA, FH, FGFR-2, MST-1R, SMAD-4, DDR-2, IGF-1R, PIK-3CB). Patients with at least 1 mutated gene of the short signature had a worse median overall survival of 8 versus 28 months (P < .001). Patients with at least 1 mutated gene of the long signature had a better median overall survival of 39 versus 20 months (P = .004). The value of the short signature was further confirmed in an independent cohort of SCLCs. CONCLUSION: The networks of mutated genes could help subclassify SCLCs based on their somatic mutations and aid in identifying a subset of tumors with poor prognosis.