A combinatorial strategy for treating KRAS-mutant lung cancer.

Therapeutic targeting of KRAS-mutant lung adenocarcinoma represents a major goal of clinical oncology. KRAS itself has proved difficult to inhibit, and the effectiveness of agents that target key KRAS effectors has been thwarted by activation of compensatory or parallel pathways that limit their efficacy as single agents. Here we take a systematic approach towards identifying combination targets for trametinib, a MEK inhibitor approved by the US Food and Drug Administration, which acts downstream of KRAS to suppress signalling through the mitogen-activated protein kinase (MAPK) cascade. Informed by a short-hairpin RNA screen, we show that trametinib provokes a compensatory response involving the fibroblast growth factor receptor 1 (FGFR1) that leads to signalling rebound and adaptive drug resistance. As a consequence, genetic or pharmacological inhibition of FGFR1 in combination with trametinib enhances tumour cell death in vitro and in vivo. This compensatory response shows distinct specificities: it is dominated by FGFR1 in KRAS-mutant lung and pancreatic cancer cells, but is not activated or involves other mechanisms in KRAS wild-type lung and KRAS-mutant colon cancer cells. Importantly, KRAS-mutant lung cancer cells and patients' tumours treated with trametinib show an increase in FRS2 phosphorylation, a biomarker of FGFR activation; this increase is abolished by FGFR1 inhibition and correlates with sensitivity to trametinib and FGFR inhibitor combinations. These results demonstrate that FGFR1 can mediate adaptive resistance to trametinib and validate a combinatorial approach for treating KRAS-mutant lung cancer.

The role of autologous stem cell transplantation (ASCT) in aggressive B-cell lymphomas: real-world data from a retrospective single-center analysis.

Patients with high-risk or relapsed aggressive B-cell lymphomas are characterized by poor prognosis. High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) can induce durable remissions in these patients and is potentially curative. Two hundred forty-seven patients with aggressive B-cell lymphomas treated with high-dose chemotherapy and ASCT, either as consolidation after first-line therapy or after salvage therapy for relapsed disease, between 2002 and 2019 at the University Hospital Muenster, were analyzed. The median follow-up of surviving patients was 36 months (range 0-163). Progression-free survival (PFS) and overall survival (OS) after 3 years was 63% and 68%, respectively. After ASCT, 28% of all patients experienced a relapse. The cumulative incidence of non-relapse mortality at day 100 after ASCT was 4%. Multivariate analysis identified remission status at ASCT, age at ASCT, and the numbers of infused CD34+ cells as independent prognostic factors for both PFS and OS. Patients with mantle cell lymphoma (MCL) or primary CNS lymphoma (PCNSL) treated with ASCT in first-line had a superior OS and PFS when compared to patients treated with ASCT in relapsed disease. For patients with diffuse large B-cell lymphoma (DLBCL) and Hodgkin lymphoma (HL), early relapse (< 12 months) after first-line therapy showed a trend towards an inferior PFS and OS. Deaths after ASCT were predominantly caused by lymphoma relapse and/or progression (64%) or due to infections (23%). In conclusion, high-dose chemotherapy followed by ASCT in the era of novel targeted agents remains a feasible and effective approach for patients with high-risk or relapsed aggressive B-cell lymphomas. Remission status and age at ASCT, and the number of infused stem cells were of prognostic relevance.

Long-term survival and polyclonal immunoglobulin reconstitution after allogeneic stem cell transplantation in multiple myeloma.

Despite significant progress made in the treatment of patients with multiple myeloma (MM) in the last decade, for patients with early relapse or rapidly progressing high-risk disease, allogeneic hematopoietic stem cell transplantation (SCT) might be an option leading to long-term survival. Here, we retrospectively analyzed the outcomes of 90 MM patients who received allogeneic SCT in our center between 1999 and 2017. We specifically assessed the association of impaired humoral immune reconstitution, referred to as immunoparesis, and post-transplant survival. Sixty-four patients received allogeneic SCT in relapse following 2-7 lines of therapy; 26 patients received upfront tandem autologous-allogeneic SCT. With a median follow-up of 76 months, OS and PFS were 52.6% (95% CI 42.9-64.3) and 36.4% (95% CI 27.6-47.9) at 2 years and 38.6% (95% CI 29.2-51.1) and 25.3% (95% CI 17.5-36.4) at 5 years, respectively. Receiving more than two therapy lines prior to transplantation was an independent risk factor for OS (HR 3.68, 95% CI 2.02-6.70) and PFS (HR 3.69, 95% CI 2.09-6.50). In a landmark analysis at day 200, prolonged immunoparesis was associated with reduced OS (HR 3.22, 95% CI 1.14-9.11). Allogeneic stem cell transplantation offers an additional treatment element that may lead to long-term remission in selected patients with poor prognosis, probably exploiting graft-versus-myeloma effects. Immunoparesis could potentially serve as an indicator for impaired survival following allogeneic transplantation, an observation to be further studied prospectively.

4D-Listmode-PET-CT and 4D-CT for optimizing PTV margins in gastric lymphoma : Determination of intra- and interfractional gastric motion.

PURPOSE: New imaging protocols for radiotherapy in localized gastric lymphoma were evaluated to optimize planning target volume (PTV) margin and determine intra-/interfractional variation of the stomach. METHODS: Imaging of 6 patients was explored prospectively. Intensity-modulated radiotherapy (IMRT) planning was based on 4D/3D imaging of computed tomography (CT) and positron-emission tomography (PET)-CT. Static and motion gross tumor volume (sGTV and mGTV, respectively) were distinguished by defining GTV (empty stomach), clinical target volume (CTV = GTV + 5 mm margin), PTV (GTV + 10/15/20/25 mm margins) plus paraaortic lymph nodes and proximal duodenum. Overlap of 4D-Listmode-PET-based mCTV with 3D-CT-based PTV (increasing margins) and V95/D95 of mCTV were evaluated. Gastric shifts were determined using online cone-beam CT. Dose contribution to organs at risk was assessed. RESULTS: The 4D data demonstrate considerable intra-/interfractional variation of the stomach, especially along the vertical axis. Conventional 3D-CT planning utilizing advancing PTV margins of 10/15/20/25 mm resulted in rising dose coverage of mCTV (4D-Listmode-PET-Summation-CT) and rising D95 and V95 of mCTV. A PTV margin of 15 mm was adequate in 3 of 6 patients, a PTV margin of 20 mm was adequate in 4 of 6 patients, and a PTV margin of 25 mm was adequate in 5 of 6 patients. CONCLUSION: IMRT planning based on 4D-PET-CT/4D-CT together with online cone-beam CT is advisable to individualize the PTV margin and optimize target coverage in gastric lymphoma.

Outcome and prognostic factors in patients undergoing salvage therapy for recurrent esophagogastric cancer after multimodal treatment.

PURPOSE: Perioperative systemic treatment has significantly improved the outcome in locally advanced esophagogastric cancer. However, still the majority of patients relapse and die. Data on the optimal treatment after relapse are limited, and clinical and biological prognostic factors are lacking. METHODS: Patients with a relapse after neoadjuvant/perioperative treatment and surgery for esophagogastric cancer were analyzed using a prospective database. Applied treatment regimens, clinical prognostic factors and biomarkers were analyzed. RESULTS: Of 246 patients 119 relapsed. Among patients with a relapse event, those with an early relapse (< 6 months) had an inferior overall survival (OS 6.3 vs. 13.8 months, p < 0.001) after relapse than those with a late relapse (> 6 months). OS after relapse was longer in patients with a microsatellite-unstable (MSI) tumor. Systemic treatment was initiated in 87 patients (73% of relapsed pat.); among those OS from the start of first-line treatment was inferior in patients with an early relapse with 6.9 vs. 10.0 months (p = 0.037). In 27 patients (23% of relapsed pat.), local therapy (irradiation or surgical intervention) was performed due to oligometastatic relapse, resulting in a prolonged OS in comparison to patients without local therapy (median OS 35.2 months vs. 7.8 months, p < 0.0001). Multivariate analysis confirmed the prognostic benefit of the MSI status and a local intervention. CONCLUSION: Patients relapsing after multimodal treatment have a heterogeneous prognosis depending on the relapse-free interval (if systemic treatment applied), extent of metastatic disease as well as MSI status. The benefit of additional local intervention after relapse should be addressed in a randomized trial.

Molecular profiling of EBV associated diffuse large B-cell lymphoma.

Epstein-Barr virus (EBV) associated diffuse large B-cell lymphoma (DLBCL) represents a rare aggressive B-cell lymphoma subtype characterized by an adverse clinical outcome. EBV infection of lymphoma cells has been associated with different lymphoma subtypes while the precise role of EBV in lymphomagenesis and specific molecular characteristics of these lymphomas remain elusive. To further unravel the biology of EBV associated DLBCL, we present a comprehensive molecular analysis of overall 60 primary EBV positive (EBV+) DLBCLs using targeted sequencing of cancer candidate genes (CCGs) and genome-wide determination of recurrent somatic copy number alterations (SCNAs) in 46 cases, respectively. Applying the LymphGen classifier 2.0, we found that less than 20% of primary EBV + DLBCLs correspond to one of the established molecular DLBCL subtypes underscoring the unique biology of this entity. We have identified recurrent mutations activating the oncogenic JAK-STAT and NOTCH pathways as well as frequent amplifications of 9p24.1 contributing to immune escape by PD-L1 overexpression. Our findings enable further functional preclinical and clinical studies exploring the therapeutic potential of targeting these aberrations in patients with EBV + DLBCL to improve outcome.

Molecular and functional profiling identifies therapeutically targetable vulnerabilities in plasmablastic lymphoma.

Plasmablastic lymphoma (PBL) represents a rare and aggressive lymphoma subtype frequently associated with immunosuppression. Clinically, patients with PBL are characterized by poor outcome. The current understanding of the molecular pathogenesis is limited. A hallmark of PBL represents its plasmacytic differentiation with loss of B-cell markers and, in 60% of cases, its association with Epstein-Barr virus (EBV). Roughly 50% of PBLs harbor a MYC translocation. Here, we provide a comprehensive integrated genomic analysis using whole exome sequencing (WES) and genome-wide copy number determination in a large cohort of 96 primary PBL samples. We identify alterations activating the RAS-RAF, JAK-STAT, and NOTCH pathways as well as frequent high-level amplifications in MCL1 and IRF4. The functional impact of these alterations is assessed using an unbiased shRNA screen in a PBL model. These analyses identify the IRF4 and JAK-STAT pathways as promising molecular targets to improve outcome of PBL patients.

Therapeutic potential of PI3K signaling in distinct entities of B-cell lymphoma.

Introduction: Aberrant phosphatidylinositide 3-kinase (PI3K) signaling drives survival and proliferation of malignant B-cells of different lymphoma entities. Thus, inhibition of PI3K isoforms represents a novel and promising therapeutic approach for the treatment of patients with B-cell lymphomas.Areas covered: Here the authors provide an overview about the PI3K signaling pathway as well as available preclinical and clinical results of different PI3K inhibitors in both indolent and aggressive lymphoma entities.Expert opinion: PI3K inhibitors have shown to be efficacious in different entities of B-cell lymphoma, at this stage particularly in relapsed/refractory settings. However, responses of PI3K inhibitors widely vary among different lymphomas. Additionally, especially infectious and immune-mediated toxicities limit their use at this stage. Thus, the decision to use PI3K inhibitors needs to be balanced between the potential efficacy and associated toxicities as well as the availability of other therapeutic options. Future research might eventually lead to the stratification of patients according to the specific oncogenic addictions of the underlying lymphoma. Additionally, PI3K inhibitors will need to be combined with other therapeutic agents for more specific and effective treatment regimens.

The dark matter of the cancer genome: aberrations in regulatory elements, untranslated regions, splice sites, non-coding RNA and synonymous mutations.

Cancer is a disease of the genome caused by oncogene activation and tumor suppressor gene inhibition. Deep sequencing studies including large consortia such as TCGA and ICGC identified numerous tumor-specific mutations not only in protein-coding sequences but also in non-coding sequences. Although 98% of the genome is not translated into proteins, most studies have neglected the information hidden in this "dark matter" of the genome. Malignancy-driving mutations can occur in all genetic elements outside the coding region, namely in enhancer, silencer, insulator, and promoter as well as in 5'-UTR and 3'-UTR Intron or splice site mutations can alter the splicing pattern. Moreover, cancer genomes contain mutations within non-coding RNA, such as microRNA, lncRNA, and lincRNA A synonymous mutation changes the coding region in the DNA and RNA but not the protein sequence. Importantly, oncogenes such as TERT or miR-21 as well as tumor suppressor genes such as TP53/p53, APC, BRCA1, or RB1 can be affected by these alterations. In summary, coding-independent mutations can affect gene regulation from transcription, splicing, mRNA stability to translation, and hence, this largely neglected area needs functional studies to elucidate the mechanisms underlying tumorigenesis. This review will focus on the important role and novel mechanisms of these non-coding or allegedly silent mutations in tumorigenesis.