Prognostic Role of Programmed Cell Death 1 Ligand 1 in Resectable Pleural Mesothelioma

BACKGROUND

The prognostic role of programmed cell death 1 ligand 1 (PD-L1) in malignant pleural mesothelioma (MPM) is incompletely understood. Our objectives were to evaluate the evidence for tumor PD-L1 as a prognostic biomarker in MPM through meta-analysis and to determine whether tumor PD-L1 expression is associated with survival in MPM patients undergoing macroscopic complete resection.

METHODS

Meta-analysis was performed to determine the association of PD-L1 with overall survival in MPM (n = 1655) from 14 studies containing overall survival and tumor PD-L1 expression. Univariable and multivariable analyses tested the relationship of tumor PD-L1 with overall survival and recurrence-free survival in an institutional cohort of MPM patients treated by macroscopic complete resection (n = 75). To validate the association of PD-L1 with overall survival, we utilized two independent MPM cohorts (n = 284).

RESULTS

Meta-analysis demonstrated that high tumor PD-L1 expression was associated with poor overall survival. Among 75 patients undergoing macroscopic complete resection, 49 tumors (65%) expressed PD-L1 (1% or more), and high PD-L1 (50% or greater) was more commonly expressed on nonepithelial (29%) compared with epithelial tumors (14%). High tumor PD-L1 expression was independently associated with poor overall survival (P < .001, hazard ratio 5.67) and recurrence-free survival (P = .003, hazard ratio 3.28). The association of PD-L1 overexpression with unfavorable survival was more significant in epithelial MPMs than nonepithelial MPMs. These findings were validated in RNA sequencing analyses in two independent cohorts. Exploratory transcriptome analysis revealed that MPM tumors with PD-L1 overexpression displayed coexpression of other immune regulatory molecules, programmed cell death 1 ligand 2 and T-cell immunoglobulin mucin receptor 3.

CONCLUSIONS

Tumor PD-L1 expression is a prognostic biomarker in patients undergoing surgical resection for MPM and may be useful in perioperative decision making.

Extended Pleurectomy and Decortication for Malignant Pleural Mesothelioma

Extended pleurectomy and decortication (ePD) is a difficult operation performed for the surgical resection of malignant pleural mesothelioma that can achieve a macroscopic complete resection with preservation of the lung. With lower perioperative mortality, similar long-term survival, and better tolerance in patients with lower performance status, ePD has become the preferred operation rather than extrapleural pneumonectomy despite lack of a direct comparison. As ePD has become more popular, international collaboration is underway to create surgical guidelines based on collection of operative data. These efforts will improve the safety and standardization of this operation.

The Staging of Malignant Pleural Mesothelioma

Staging of malignant pleural mesothelioma has been challenging because of a paucity of cases and poor survival. At least 5 staging systems were proposed before 1990 until the first consensus system was published in 1995. This system used tumor, node, metastasis designations and borrowed heavily from parenchymal lung cancer descriptors. With the establishment of a database to collect cases from 1995 to 2013, evidence-based revisions to the 1995 staging classification were published in 2016. With improving imaging technology, clinical staging will become more refined and, it is hoped, more useful for prognostication even without operative resection.

Trends in Major Gastrectomy for Cancer: Frequency and Outcomes

BACKGROUND

Declining incidence of gastric cancer in the USA has presumably resulted in lower rates of major gastrectomy for cancer. The impact on perioperative outcomes remains undefined. The aims of this study were to characterize national trends in frequency of major gastrectomy for cancer, identify factors associated with in-hospital mortality, and examine outcome disparities by race/ethnicity.

METHODS

Nationwide inpatient sample data from 1993 to 2013 were queried for procedural and diagnostic codes (ICD-9) relating to total and partial gastrectomy procedures. Gastric resections for cancer were compared to those for peptic ulcer disease for reference. Patient demographics, comorbidity score, mortality, and hospital characteristics were recorded as covariates.

RESULTS

A significant decrease in annual rates of partial and total gastrectomy was observed from 1993 to 2013 (p < 0.0001). The change in absolute number and percent decline was greater for partial gastrectomy (- 39.3%) than total gastrectomy (- 19%). There was a 34.0% decrease in gastrectomy for cancer in Whites and a 61.2% increase among Hispanic patients over two decades. In-hospital mortality also significantly decreased over the study period (7.7% to 2.7%). Factors associated with lower mortality rates included male sex and treatment at urban teaching hospitals. Analysis of trends revealed that gastrectomy for cancer was performed with increasing frequency at urban teaching hospitals.

CONCLUSIONS

The frequency of major gastric resections in the USA has declined over two decades. Overall, in-hospital mortality rates also have decreased significantly. Declining in-hospital mortality after gastrectomy for cancer is associated with more frequent treatment at urban teaching hospitals.

MicroRNA-215-5p Treatment Suppresses Mesothelioma Progression via the MDM2-p53-Signaling Axis

Malignant pleural mesothelioma (MPM) is an incurable, aggressive neoplasm with distinctive features, including preservation of wild-type p53, irrespective of histologic subtype. We posited that this consistent molecular characteristic represents an underexploited therapeutic target that can be approached by leveraging biologic effects of microRNA (miRNA). The Cancer Genome Atlas was surveyed to identify p53-responsive prognostic miRNA(s) in MPM. Using patient samples, in vitro MPM cell lines, and murine tumor xenograft models, we verified specific gene pathways targeted by these miRNAs, and we examined their therapeutic effects. miR-215-5p is a poor prognosis miRNA downregulated in MPM tissues, which has not been recognized previously. When miR-215-5p was ectopically re-expressed in MPM cells and delivered in vivo to tumor xenografts, it exerted significant cell killing by activating p53 function and inducing apoptosis. The mechanistic basis for this effect is due to combinatorial effects of a positive feedback loop of miR-215-MDM2-p53 signaling, additional mouse double minute 2 (MDM2)-p53 positive feedback loop(s) with other miRNAs such as miR-145-5p, and suppression of diverse gene targets associated with cell cycle dynamics not previously drug treatable in MPM clinical studies. Our results suggest a potential pathophysiologic role for and therapeutic significance of miR-215-5p in MPM.

Metadherin Is a Prognostic Apoptosis Modulator in Mesothelioma Induced via NF-κB-Mediated Signaling

Therapies against malignant pleural mesothelioma (MPM) have yielded disappointing results, in part, because pathologic mechanisms remain obscure. In searching for rational molecular targets, we identified metadherin (MTDH), a multifunctional gene associated with several tumor types but previously unrecognized in MPM. Cox proportional hazards regression analysis delineated associations between higher MTDH expression and lower patient survival from three independent MPM cohorts (n = 349 patients). Through in vitro assays with overexpression and downregulation constructs in MPM cells, we characterized the role of MTDH. We confirmed in vivo the phenotype of altered MTDH expression in a murine xenograft model. Transcriptional regulators of MTDH were identified by chromatin immunoprecipitation. Overexpression of both MTDH mRNA (12-fold increased) and protein levels was observed in tumor tissues. MTDH stable overexpression significantly augmented proliferation, invasiveness, colony formation, chemoresistance, and an antiapoptosis phenotype, while its suppression showed opposite effects in MPM cells. Interestingly, NF-κB and c-Myc (in a feed-forward loop motif) contributed to modulating MTDH expression. Knockdown of MTDH expression profoundly retarded xenograft tumor growth. Thus, our findings support the notion that MTDH integrates upstream signals from certain transcription factors and mediates pathogenic interactions contributing to MPM traits. MTDH represents a new MPM-associated gene that can contribute to insights of MPM biology and, as such, suggest other treatment strategies.

A Phase II Trial of Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy for Recurrent Adrenocortical Carcinoma

BACKGROUND

Recurrent adrenocortical carcinoma (ACC) is an aggressive disease with few options offering durable survival benefit. Despite metastasectomy, recurrence is common. Cytoreduction and intraperitoneal chemotherapy have offered improved survival in other advanced cancers. We sought to evaluate the use of cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC) for the treatment of recurrent intraperitoneal ACC.

METHODS

A phase II, single institution clinical trial was approved for patients with radiographic evidence of resectable ACC limited to the peritoneum. Patients underwent treatment if optimal cytoreduction was deemed possible at exploratory laparotomy. Primary outcome was intraperitoneal progression-free survival. Secondary outcomes were treatment-related morbidities and overall survival.

RESULTS

Sixty-three patients were evaluated, of whom 11 met eligibility criteria. Nine patients underwent cytoreduction and HIPEC, including one patient who recurred and was re-treated (n = 10 treatments). One patient could not be optimally cytoreduced for HIPEC and therefore did not receive intraperitoneal chemotherapy. There was no perioperative mortality; perioperative comorbidities were limited to Clavien-Dindo grade 2 or 3 and included hematologic, infectious, and neurologic complications. Seven patients experienced disease recurrence and two patients died of disease during follow-up (median 24 mo). Intraperitoneal progression-free survival was 19 mo, and median overall survival has not yet been reached.

CONCLUSIONS

Cytoreduction and HIPEC can be performed safely in selected patients. Patients with recurrent ACC confined to the peritoneal cavity can be considered for regional therapy in experienced hands. However, disease recurrence is common, and other treatment options should be explored.