Genomic characterization of metastatic patterns from prospective clinical sequencing of 25,000 patients.

Metastatic progression is the main cause of death in cancer patients, whereas the underlying genomic mechanisms driving metastasis remain largely unknown. Here, we assembled MSK-MET, a pan-cancer cohort of over 25,000 patients with metastatic diseases. By analyzing genomic and clinical data from this cohort, we identified associations between genomic alterations and patterns of metastatic dissemination across 50 tumor types. We found that chromosomal instability is strongly correlated with metastatic burden in some tumor types, including prostate adenocarcinoma, lung adenocarcinoma, and HR+/HER2+ breast ductal carcinoma, but not in others, including colorectal cancer and high-grade serous ovarian cancer, where copy-number alteration patterns may be established early in tumor development. We also identified somatic alterations associated with metastatic burden and specific target organs. Our data offer a valuable resource for the investigation of the biological basis for metastatic spread and highlight the complex role of chromosomal instability in cancer progression.

Mesothelioma: Scientific clues for prevention, diagnosis, and therapy.

Mesothelioma affects mostly older individuals who have been occupationally exposed to asbestos. The global mesothelioma incidence and mortality rates are unknown, because data are not available from developing countries that continue to use large amounts of asbestos. The incidence rate of mesothelioma has decreased in Australia, the United States, and Western Europe, where the use of asbestos was banned or strictly regulated in the 1970s and 1980s, demonstrating the value of these preventive measures. However, in these same countries, the overall number of deaths from mesothelioma has not decreased as the size of the population and the percentage of old people have increased. Moreover, hotspots of mesothelioma may occur when carcinogenic fibers that are present in the environment are disturbed as rural areas are being developed. Novel immunohistochemical and molecular markers have improved the accuracy of diagnosis; however, about 14% (high-resource countries) to 50% (developing countries) of mesothelioma diagnoses are incorrect, resulting in inadequate treatment and complicating epidemiological studies. The discovery that germline BRCA1-asssociated protein 1 (BAP1) mutations cause mesothelioma and other cancers (BAP1 cancer syndrome) elucidated some of the key pathogenic mechanisms, and treatments targeting these molecular mechanisms and/or modulating the immune response are being tested. The role of surgery in pleural mesothelioma is controversial as it is difficult to predict who will benefit from aggressive management, even when local therapies are added to existing or novel systemic treatments. Treatment outcomes are improving, however, for peritoneal mesothelioma. Multidisciplinary international collaboration will be necessary to improve prevention, early detection, and treatment.

Comparison of Immunohistochemistry, Next-generation Sequencing and Fluorescence In Situ Hybridization for Detection of MTAP Loss in Pleural Mesothelioma.

9p21 deletions involving MTAP/CDKN2A genes are detected in diffuse pleural mesotheliomas (DPM) but are absent in benign mesothelial proliferations. Loss of MTAP expression by immunohistochemistry (IHC) is well accepted as a surrogate for 9p21 deletion to support a diagnosis of DPM. Accurate interpretation can be critical in the diagnosis of DPM, but variations in antibody performance may impact interpretation. The objectives of this study were to compare the performance of MTAP monoclonal antibodies (mAbs) EPR6893 and 1813 and to compare MTAP expression by IHC with 9p21 copy number status in DPM. Cytoplasmic expression of MTAP IHC with mAbs EPR6893 (ab126770; Abcam) and 1813 (NBP2-75730, Novus Biologicals) was evaluated in 56 DPM (47 epithelioid, 7 biphasic, and 2 sarcomatoid) profiled by targeted next-generation sequencing. 9p21 Copy number status was assessed by Fraction and Allele-Specific Copy Number Estimates from Tumor Sequencing (FACETS) analysis and also by CDKN2A fluorescence in situ hybridization in discrepant cases when material was available. MTAP mAb 1813 showed stronger immunoreactivity, more specific staining, and no equivocal interpretations compared to mAb EPR6893 which showed equivocal staining in 19 (34%) of cases due to weak or heterogenous immunoreactivity, lack of definitive internal positive control, and/or nonspecific background staining. MTAP expression with mAb 1813 showed near perfect agreement with 9p21 copy number by combined FACETS/fluorescence in situ hybridization calls (κ = 0.85; 95% CI, 0.71-0.99; P < .001). MTAP IHC with mAb 1813 was 96% sensitive, 86% specific, and 93% accurate for 9p21 homozygous deletion. The findings of this study suggest that interpretation of MTAP IHC is improved with mAb 1813 because mAb EPR6893 was often limited by equivocal interpretations. We show that MTAP IHC and molecular assays are complementary in detecting 9p21 homozygous deletion. MTAP IHC may be particularly useful for low tumor purity samples and in low-resource settings.

Neurofibromatosis Type 2-Yes-Associated Protein and Transcriptional Coactivator With PDZ-Binding Motif Dual Immunohistochemistry Is a Reliable Marker for the Detection of Neurofibromatosis Type 2 Alterations in Diffuse Pleural Mesothelioma.

Neurofibromatosis type 2 (NF2) loss occurs in approximately 30% to 50% of diffuse pleural mesothelioma (DPM) with accumulation of yes-associated protein (YAP) 1 and transcriptional coactivator with PDZ-binding motif (TAZ) in tumor nuclei. NF2 and YAP/TAZ represent potential therapeutic targets. We investigated the performance of NF2-YAP/TAZ dual immunohistochemistry (IHC) in identifying DPM that harbors NF2 alterations and in distinguishing DPM from benign mesothelial proliferations. NF2-YAP/TAZ IHC was subsequently performed in a Discovery cohort of DPMs with (n = 10) or without (n = 10) NF2 alterations detected by next-generation sequencing (NGS) and 9 benign cases. The cutoff values for loss of NF2 expression and YAP/TAZ overexpression using IHC were determined in the Discovery cohort. The performance characteristics of NF2-YAP/TAZ IHC were investigated in a Validation cohort (20 DPMs and 10 benign cases). In the Discovery cohort, all DPMs with NF2 alterations using NGS showed NF2 IHC scores of <2, whereas all NF2-wild-type DPMs showed scores of ≥2. NF2-altered DPMs had significantly higher YAP/TAZ H-scores (P < .001) than NF2-wild-type DPM and benign pleura (median H-scores: 237.5 [range, 185-275], 130.0 [range, 40-225], and 10.0 [range, 0-75], respectively). NF2-YAP/TAZ IHC demonstrated 95.2% sensitivity, 100% specificity, 100% positive predictive value, and 95% negative predictive value for detecting NF2 alterations in DPM (n = 40) with NGS as the gold standard and 87.5% sensitivity and 100% specificity for distinguishing DPM (n = 40) from benign mesothelial proliferations (n = 19). NF2-YAP/TAZ IHC has a high sensitivity and specificity for detecting NF2 alterations in DPM and a high specificity for malignancy, highlighting potential utility for guiding NF2-targeted therapies and distinguishing DPM from benign mimics.

EZH2 inhibitor tazemetostat in patients with relapsed or refractory, BAP1-inactivated malignant pleural mesothelioma: a multicentre, open-label, phase 2 study.

BACKGROUND: Treatment options for malignant pleural mesothelioma are scarce. Tazemetostat, a selective oral enhancer of zeste homolog 2 (EZH2) inhibitor, has shown antitumour activity in several haematological cancers and solid tumours. We aimed to evaluate the anti-tumour activity and safety of tazemetostat in patients with measurable relapsed or refractory malignant pleural mesothelioma. METHODS: We conducted an open-label, single-arm phase 2 study at 16 hospitals in France, the UK, and the USA. Eligible patients were aged 18 years or older with malignant pleural mesothelioma of any histology that was relapsed or refractory after treatment with at least one pemetrexed-containing regimen, an Eastern Cooperative Oncology Group performance status of 0 or 1, and a life expectancy of greater than 3 months. In part 1 of the study, participants received oral tazemetostat 800 mg once on day 1 and then twice daily from day 2 onwards. In part 2, participants received oral tazemetostat 800 mg twice daily starting on day 1 of cycle 1, using a two-stage Green-Dahlberg design. Tazemetostat was administered in 21-day cycles for approximately 17 cycles. The primary endpoint of part 1 was the pharmacokinetics of tazemetostat and its metabolite at day 15 after administration of 800 mg tazemetostat, as measured by maximum serum concentration (Cmax), time to Cmax (Tmax), area under the concentration-time curve (AUC) to day 15 (AUC0-t), area under the curve from time 0 extrapolated to infinity (AUC0-∞), and the half-life (t1/2) of tazemetostat, assessed in all patients enrolled in part 1. The primary endpoint of part 2 was the disease control rate (the proportion of patients with a complete response, partial response, or stable disease) at week 12 in patients with malignant pleural mesothelioma per protocol with BAP1 inactivation determined by immunohistochemistry. The safety population included all the patients who had at least one post-dose safety assessment. This trial is now complete and is registered with ClinicalTrials.gov, NCT02860286. FINDINGS: Between July 29, 2016, and June 2, 2017, 74 patients were enrolled (13 in part 1 and 61 in part 2) and received tazemetostat, 73 (99%) of whom had BAP1-inactivated tumours. In part 1, following repeat dosing of tazemetostat at steady state, on day 15 of cycle 1, the mean Cmax was 829 ng/mL (coefficient of variation 56·3%), median Tmax was 2 h (range 1-4), mean AUC0-twas 3310 h·ng/mL (coefficient of variation 50·4%), mean AUC0-∞ was 3180 h·ng/mL (46·6%), and the geometric mean t1/2 was 3·1 h (13·9%). After a median follow-up of 35·9 weeks (IQR 20·6-85·9), the disease control rate in part 2 in patients with BAP1-inactivated malignant pleural mesothelioma was 54% (95% CI 42-67; 33 of 61 patients) at week 12. No patients had a confirmed complete response. Two patients had a confirmed partial response: one had an ongoing partial response with a duration of 18 weeks and the other had a duration of 42 weeks. The most common grade 3-4 treatment-emergent adverse events were hyperglycaemia (five [7%] patients), hyponatraemia (five [7%]), and anaemia (four [5%]); serious adverse events were reported in 25 (34%) of 74 patients. Five (7%) of 74 patients died while on study; no treatment-related deaths occurred. INTERPRETATION: Further refinement of biomarkers for tazemetostat activity in malignant pleural mesothelioma beyond BAP1 inactivation could help identify a subset of tumours that are most likely to derive prolonged benefit or shrinkage from this therapy. FUNDING: Epizyme.

Phase 1 cohort expansion study of LY3023414, a dual PI3K/mTOR inhibitor, in patients with advanced mesothelioma.

BACKGROUND LY3023414 is a selective, ATP competitive inhibitor of class I PI3K isoforms, mTORC1/2 and DNA-PK. A Phase 1 dose escalation, 200 mg twice daily (BID) of LY3023414 was the determined recommended phase 2 dose (RP2D). We report the antitumor activity and safety of LY3023414 monotherapy in patients with advanced mesothelioma.METHODS Patients enrolled had advanced malignant pleural or peritoneal mesothelioma with measurable disease, ECOG PS 0-1, were refractory or ineligible to receive standard therapies. Patients received LY3023414 200 mg BID. This dose expansion cohort is intended to evaluate preliminary antitumor activity of LY3023414 by overall response rate. Safety, tolerability and pharmacokinetics were assessed. Biomarkers associated with treatment response was an exploratory endpoint. RESULTS Forty-two patients received LY3023414 for a median duration of 11.2 weeks (range: 1.1-53.0). One patient had a confirmed partial response (PR) (ORR 2.4%). Three patients had an unconfirmed PR. Seventeen patients had stable disease (SD) (DCR 43%). Most common adverse events (AEs) included fatigue (43%), nausea (43%), decreased appetite (38%), vomiting (33%), and diarrhea (29%). AEs were mostly mild or moderate. Grade ≥ 3 AEs were reported for 21% of patients with fatigue as the most frequent event (10%). Alterations of BAP1 were identified in 11/19 patients as the most common molecular aberration, followed by SETD2 and NF2 alterations. No obvious pattern of genetic changes/mutations in single genes or pathways was associated with anti-tumor activity. CONCLUSION LY3023414 monotherapy (200 mg BID) demonstrated an acceptable and manageable safety profile with limited single-agent activity in patients with advanced mesothelioma. ClinicalTrials.gov identifier: NCT01655225; Date of registration: 19 July 2012.

V-domain Ig-containing suppressor of T-cell activation (VISTA), a potentially targetable immune checkpoint molecule, is highly expressed in epithelioid malignant pleural mesothelioma.

V-domain Ig-containing suppressor of T-cell activation (VISTA) is an immune checkpoint gene that inhibits anti-tumor immune responses. Since most malignant pleural mesotheliomas do not respond to anti-programmed cell death(-ligand)1 (PD-(L)1)/cytotoxic T-lymphocyte-associated protein 4 (CTLA4) therapy and given the recent finding of The Cancer Genome Atlas Study that pleural mesothelioma displays the highest expression of VISTA among all cancers studied, we examined VISTA expression in a large pleural mesothelioma cohort. VISTA and PD-L1 immunohistochemistry were performed on tissue microarray of immunotherapy-naive pleural mesotheliomas (254 epithelioid, 24 biphasic and 41 sarcomatoid) and ten whole-tissue sections of benign pleura (VISTA only). Percentages of tumor and inflammatory cells with positive staining were assessed. Optimal prognostic cutoff percentages were determined using maximally selected rank statistics. Overall survival was evaluated using Kaplan-Meier methods and Cox proportional hazard analysis. All benign mesothelium expressed VISTA. Eighty-five percent of 319 and 38% of 304 mesotheliomas expressed VISTA and PD-L1 (88% and 33% of epithelioid, 90% and 43% of biphasic, and 42% and 75% of sarcomatoid), respectively. Median VISTA score was significantly higher in epithelioid (50%) (vs. biphasic [20%] and sarcomatoid [0]) (p < 0.001), while median PD-L1 score was significantly higher in sarcomatoid tumors (20%) (vs. biphasic and epithelioid [both 0%]) (p < 0.001). VISTA and PD-L1 were expressed in inflammatory cells in 94% (n = 317) and 24% (n = 303) of mesothelioma, respectively. Optimal prognostic cutoffs for VISTA and PD-L1 were 40% and 30%, respectively. On multivariable analysis, VISTA and PD-L1 expression in mesothelioma were associated with better and worse overall survival (p = 0.001 and p = 0.002), respectively, independent of histology. In a large cohort of mesothelioma, we report frequent expression of VISTA and infrequent expression of PD-L1 with favorable and unfavorable survival correlations, respectively. These findings may explain poor responses to anti-PD-(L)1 immunotherapy and suggest VISTA as a potential novel target in pleural mesothelioma.

A phase Ib study of GSK3052230, an FGF ligand trap in combination with pemetrexed and cisplatin in patients with malignant pleural mesothelioma.

Background Fibroblast growth factors (FGFs) have a fundamental role in cancer. Sequestering FGFs with GSK3052230 (FP-1039) blocks their ability to activate FGFRs while avoiding toxicities associated with small molecule inhibitors of FGFR, including hyperphosphatemia and retinal, nail, and skin toxicities. Methods A multicenter, open-label, phase Ib study evaluated weekly GSK3052230 added to pemetrexed/cisplatin in patients with treatment-naive, unresectable malignant pleural mesothelioma. Doses were escalated according to a 3 + 3 design, followed by cohort expansion at the maximum tolerated dose (MTD). Endpoints included safety, overall response rate, progression-free survival, and pharmacokinetics. Results 36 patients were dosed at 10, 15, and 20 mg/kg doses of GSK3052230. Three dose-limiting toxicities were observed at 20 mg/kg and one at 15 mg/kg. The MTD was defined as 15 mg/kg and used for cohort expansion. The most common treatment-related adverse events (AEs) were nausea (56%), decreased appetite (36%), infusion reactions (36%), decreased neutrophil counts (36%), and fatigue (33%). The confirmed ORR was 39% (95% CI: 23.1-56.5) (14/36 PRs) and 47% had stable disease (17/36), giving a disease control rate of 86%. At 15 mg/kg GSK3052230 (n = 25), the ORR was 44% (95% CI: 24.4-65.1), and the median PFS was 7.4 months (95% CI: 6.7-13.4). Four patients had disease control for over 1 year, and three were still ongoing. Conclusion At 15 mg/kg weekly, GSK3052230 was well tolerated in combination with pemetrexed/cisplatin and durable responses were observed. Importantly, AEs associated with small molecule inhibitors of FGFR were not observed, as predicted by the unique mechanism of action of this drug.

Workshop summary: Potential usefulness and feasibility of a US National Mesothelioma Registry.

The burden and prognosis of malignant mesothelioma in the United States have remained largely unchanged for decades, with approximately 3200 new cases and 2400 deaths reported annually. To address care and research gaps contributing to poor outcomes, in March of 2019 the Mesothelioma Applied Research Foundation convened a workshop on the potential usefulness and feasibility of a national mesothelioma registry. The workshop included formal presentations by subject matter experts and a moderated group discussion. Workshop participants identified top priorities for a registry to be (a) connecting patients with high-quality care and clinical trials soon after diagnosis, and (b) making useful data and biospecimens available to researchers in a timely manner. Existing databases that capture mesothelioma cases are limited by factors such as delays in reporting, deidentification, and lack of exposure information critical to understanding as yet unrecognized causes of disease. National disease registries for amyotrophic lateral sclerosis (ALS) in the United States and for mesothelioma in other countries, provide examples of how a registry could be structured to meet the needs of patients and the scientific community. Small-scale pilot initiatives should be undertaken to validate methods for rapid case identification, develop procedures to facilitate patient access to guidelines-based standard care and investigational therapies, and explore approaches to data sharing with researchers. Ultimately, federal coordination and funding will be critical to the success of a National Mesothelioma Registry in improving mesothelioma outcomes and preventing future cases of this devastating disease.

Malignant Pleural Mesothelioma: Are There Imaging Characteristics Associated With Different Histologic Subtypes on Computed Tomography?

OBJECTIVES: Determine imaging characteristics specific to epithelioid (eMPM), sarcomatoid (sMPM), and biphasic (bMPM) subtypes of malignant pleural mesothelioma (MPM) on computed tomography. METHODS: Preoperative computed tomography scans of patients with MPM were retrospectively assessed for numerous features including primary affected side, volume loss, pleural thickness, pleural calcifications, pleural effusion, and lymphadenopathy. RESULTS: One hundred twenty-five patients with MPM were included. Histologic subdivision was 97 eMPM (77%), 17 bMPM (14%), and 11 sMPM (9%). Nonepithelioid MPM (bMPM and sMPM) was more likely than eMPM to have calcified pleural plaques (P = 0.035). Analyzed separately, bMPM and sMPM each demonstrated calcified plaques more frequently than eMPM, and sMPM more often had internal mammary nodes; however, P values did not reach significance (P = 0.075 and 0.071, respectively). CONCLUSIONS: Calcified plaques are significantly more common in nonepithelioid subtypes compared with eMPM. Given the different prognoses and management of MPM subtypes, accurate noninvasive subtype classification is clinically vital.

Alcohol and lung cancer risk among never smokers: A pooled analysis from the international lung cancer consortium and the SYNERGY study.

It is not clear whether alcohol consumption is associated with lung cancer risk. The relationship is likely confounded by smoking, complicating the interpretation of previous studies. We examined the association of alcohol consumption and lung cancer risk in a large pooled international sample, minimizing potential confounding of tobacco consumption by restricting analyses to never smokers. Our study included 22 case-control and cohort studies with a total of 2548 never-smoking lung cancer patients and 9362 never-smoking controls from North America, Europe and Asia within the International Lung Cancer Consortium (ILCCO) and SYNERGY Consortium. Alcohol consumption was categorized into amounts consumed (grams per day) and also modelled as a continuous variable using restricted cubic splines for potential non-linearity. Analyses by histologic sub-type were included. Associations by type of alcohol consumed (wine, beer and liquor) were also investigated. Alcohol consumption was inversely associated with lung cancer risk with evidence most strongly supporting lower risk for light and moderate drinkers relative to non-drinkers (>0-4.9 g per day: OR = 0.80, 95% CI = 0.70-0.90; 5-9.9 g per day: OR = 0.82, 95% CI = 0.69-0.99; 10-19.9 g per day: OR = 0.79, 95% CI = 0.65-0.96). Inverse associations were found for consumption of wine and liquor, but not beer. The results indicate that alcohol consumption is inversely associated with lung cancer risk, particularly among subjects with low to moderate consumption levels, and among wine and liquor drinkers, but not beer drinkers. Although our results should have no relevant bias from the confounding effect of smoking we cannot preclude that confounding by other factors contributed to the observed associations. Confounding in relation to the non-drinker reference category may be of particular importance.

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.

Diffuse Pleural Mesothelioma: Advances in Molecular Pathogenesis, Diagnosis, and Treatment.

Diffuse pleural mesothelioma (DPM) is a highly aggressive malignant neoplasm arising from the mesothelial cells lining the pleural surfaces. While DPM is a well-recognized disease linked to asbestos exposure, recent advances have expanded our understanding of molecular pathogenesis and transformed our clinical practice. This comprehensive review explores the current concepts and emerging trends in DPM, including risk factors, pathobiology, histologic subtyping, and therapeutic management, with an emphasis on a multidisciplinary approach to this complex disease.

The BAP1 nuclear deubiquitinase is involved in the nonhomologous end-joining pathway of double-strand DNA repair through interaction with DNA-PK.

BRCA1-associated protein 1 (BAP1) has emerged as a major tumor suppressor gene in diverse cancer types, notably in malignant pleural mesothelioma (DPM), and has also been identified as a germline cancer predisposition gene for DPM and other select cancers. However, its role in the response to DNA damage has remained unclear. Here, we show that BAP1 inactivation is associated with increased DNA damage both in Met-5A human mesothelial cells and human DPM cell lines. Through proteomic analyses, we identified PRKDC as an interaction partner of BAP1 protein complexes in DPM cells and 293 T human embryonic kidney cells. PRKDC encodes the catalytic subunit of DNA protein kinase (DNA-PKcs) which functions in the nonhomologous end-joining (NHEJ) pathway of DNA repair. Double-stranded DNA damage resulted in prominent nuclear expression of BAP1 in DPM cells and phosphorylation of BAP1 at serine 395. A plasmid-based NHEJ assay confirmed a significant effect of BAP1 knockdown on cellular NHEJ activity. Combination treatment with X-ray irradiation and gemcitabine (as a radiosensitizer) strongly suppressed the growth of BAP1-deficient cells. Our results suggest reciprocal positive interactions between BAP1 and DNA-PKcs, based on phosphorylation of BAP1 by the latter and deubiquitination of DNA-PKcs by BAP1. Thus, functional interaction of BAP1 with DNA-PKcs supports a role for BAP1 in NHEJ DNA repair and may provide the basis for new therapeutic strategies and new insights into its role as a tumor suppressor.

Safety and efficacy of percutaneous cryoablation for primary and metastatic pleural based tumors.

PURPOSE: Assess safety and local tumor progression-free survival (LTPFS) of percutaneous cryoablation for pleural-based thoracic malignancies. MATERIALS AND METHODS: Retrospective study of 46 patients (17 treated for palliation; 9 for oligoprogression; 20 for curative intent), with 62 pleural-based thoracic lesions, treated in 59 cryoablation sessions. Patients were treated from 9/2005-11/2021 with CryoCare CS (Varian, Irvine, CA) or IceFORCE (Boston Scientific, Marlborough, MA) systems. For tumors treated with curative intent and/or oligoprogression, LTPFS of the treated tumor(s) and overall survival (OS) were estimated using Kaplan-Meier method. Post-operative complications were reported for all sessions, including those with palliative intent; univariate analyses were used to calculate factors associated with increased complication risk. RESULTS: Median number of tumors treated in a single treatment session was 1 (range 1-4). Largest dimension of the treated tumor was 2.1 cm [IQR:0.9-5 cm]. Of the 59 treatments, 98.3 % were technically successful. Median LTPFS was 14.4 (95 % CI: 9.4-25.6) months. Tumor size was a significant predictor of LTPFS (HR: 1.21, 95 % CI: 1.03-1.44, p = 0.023). Median OS was 52.4 (28.1-NR) months. Complications occurred in 28/59 sessions (47.5 %); 2/59 (3.4 %) were ≥ grade D by Society of Interventional Radiology adverse event criteria (death; hypoxia requiring supplemental oxygen upon discharge). Pain and pneumothorax were the most common complications. The length of lung parenchyma traversed was a significant predictor of pneumothorax: HR 0.48 (95 %CI: 0.14-0.83), p = 0.0024. CONCLUSION: Percutaneous cryoablation for pleural lesions is associated with a long duration of local control and most complications were minor and self-limited.

Leveraging the pleural space for anticancer therapies in pleural mesothelioma.

Most patients with pleural mesothelioma (PM) present with symptomatic pleural effusion. In some patients, PM is only detectable on the pleural surfaces, providing a strong rationale for intrapleural anticancer therapy. In modern prospective studies involving expert radiological staging and specialist multidisciplinary teams, the population incidence of stage I PM (an approximate surrogate of pleura-only PM) is higher than in historical retrospective series. In this Viewpoint, we advocate for the expansion of intrapleural trials to serve these patients, given the paucity of data supporting licensed systemic therapies in this setting and the uncertainties involved in surgical therapy. We begin by reviewing the unique anatomical and physiological features of the PM-bearing pleural space, before critically appraising the evidence for systemic therapies in stage I PM and previous intrapleural PM trials. We conclude with a summary of key challenges and potential solutions, including optimal trial designs, repurposing of indwelling pleural catheters, and new technologies.

Diffuse Pleural Mesotheliomas with Genomic Near-Haploidization: A Newly Recognized Subset with Distinct Clinical, Histologic, and Molecular Features.

PURPOSE: Diffuse pleural mesotheliomas (DPM) with genomic near-haploidization (GNH) represent a novel subtype first recognized by The Cancer Genome Atlas project; however, its clinicopathologic and molecular features remain poorly defined. EXPERIMENTAL DESIGN: We analyzed clinical genomic profiling data from 290 patients with DPM using the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) assay. Allele-specific copy number analysis was performed using the Fraction and Allele-Specific Copy Number Estimates from Tumor Sequencing (FACETS) algorithm. RESULTS: A total of 210 patients were evaluable for loss of heterozygosity (LOH) analysis using FACETS from MSK-IMPACT tumor:normal sequencing data. In this cohort, GNH, defined as LOH across >80% of the genome, was detected in 10 cases (4.8%). Compared with non-GNH tumors, GNH DPMs were associated with younger age and less frequent self-reported history of occupational asbestos exposure. Histologically, GNH DPMs were enriched in biphasic subtype (80% vs. 14.5%) and showed abundant tumor-infiltrating lymphocytes (TILs). Genomic analysis revealed a higher frequency of TP53 alterations, whereas SETDB1 mutations were present in nearly all and only in this subset. The clinicopathologic and molecular findings were further validated in a separate cohort. Despite the younger age, patients with GNH DPMs had a shorter overall survival (10.9 vs. 25.4 months, P = 0.004); the poor prognostic impact of GNH remained significant after controlling for biphasic histology. Of three patients with GNH DPMs who received immune checkpoint blockade, two achieved a clinician-assessed partial response. CONCLUSIONS: GNH defines an aggressive subtype of mainly biphasic DPMs in younger patients with recurrent alterations in SETDB1 and TP53. The enrichment in biphasic histology and TILs, together with our preliminary immune checkpoint blockade response data and anecdotal clinical trial data, suggests that further evaluation of immunotherapy may be warranted in this subset.