Pleurectomy Decortication in the Treatment of Malignant Pleural Mesothelioma: Encouraging Results and Novel Prognostic Implications Based on Experience in 355 Consecutive Patients.

OBJECTIVE: We report a series of 355 consecutive patients treated over 9 years in a single institution with intended PDC. BACKGROUND: Surgery for MPM has shifted from extra-pleural pneumonectomy to PDC with the goal of MCR. METHODS: Clinical and outcome data were reviewed. Kaplan-Meier estimators and log rank test were used to compare the overall survival, and logistic regression models were used. RESULTS: MCR was achieved in 304. There were 223 males, median age was 69 and histology was epithelioid in 184. The 30 and 90-day mortality were 3.0% and 4.6%.Most complications were low grade. Prolonged air leak in 141, deep venous thrombosis in 64, Atrial fibrillation in 42, chylothorax in 24, Empyema in 23, pneumonia in 21, Hemothorax in 12 and pulmonary embolus in 8. Median/5-year survival were 20.7 months/17.9% in the intent-to-treat cohort and 23.2months/21.2% in the MCR group. The survivals were best for patients with Tlstage and epithelioid histology (69.8months/54.1%). In a multivariable analysis, factors that were found to be associated with longer patient overall survival included epithelioid histology, T stage, quantitative clinical stage/tumor volume staging, adjuvant chemotherapy, intraoperative heated chemo, female sex, and length of stay shorter than 14 days. CONCLUSIONS: PDC is feasible with low mortality and is associated with manageable complication rates. 5-year survival of patients undergoing PDC with MCR in multi-modality setting is approaching 25% depending on quantitative and clinical stage, sex and histological subtype and is better than PDC without- MCR.

New Concepts in the Treatment of Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma (MPM) is a highly aggressive and generally incurable cancer. Current anti-MPM chemotherapy-based treatments are only marginally effective, and long-term survival remains an unmet goal. Nonetheless, in selected cases, personalized surgery-based multimodality treatments (MMT) have been shown to significantly extend survival. The design of MMT and selection of patients are challenging, and optimal results require accurate presurgical diagnosis, staging, and risk stratification. Further, meticulous surgical techniques and advanced radiation protocols must be applied. We review key principles and evolving concepts in the care of MPM patients with a focus on the expanding role of MMT in MPM.

Diagnostic value of biopsy sampling in predicting histology in patients with diffuse malignant pleural mesothelioma.

BACKGROUND: The classification of diffuse malignant mesothelioma into epithelioid, biphasic, and sarcomatoid types is based on histologic patterns. The diagnosis is made on biopsies, and because of intratumoral heterogeneity, they may not be representative of the entire tumor. The number and volume of biopsies needed to reach diagnostic accuracy in diffuse malignant mesothelioma and their prognostic value remain unclear. METHODS: This study examined 759 consecutive patients with pleural diffuse malignant mesothelioma treated by pleurectomy/decortication or extrapleural pneumonectomy for the presence of epithelioid and/or sarcomatoid histology and classified both the presurgery biopsies (core-needle or thoracoscopic) and surgical resection specimens. The number and volume of biopsies were correlated with pre- and postsurgery histologies and overall survival. RESULTS: Diffuse malignant mesothelioma was classified as epithelioid (76%), biphasic (18%), sarcomatoid (5%), or indeterminate (1%) in biopsies and as epithelioid (64%), biphasic (32%), and sarcomatoid (4%) in surgical resection specimens (overall concordance, 80.6%). The positive likelihood ratios were 2.4, 13.6, and 90.1 for biopsies with epithelioid, biphasic, and sarcomatoid histologies, respectively. Concordant histologies between biopsies and resections were associated with a higher number of biopsies (median tissue blocks for concordant histologies vs discordant histologies, 3 vs 2; P < .002) but were less associated with a higher volume (median, 1.2 vs 1.1 cm3 ; P = .06). In a multivariate analysis, overall survival was independently predicted by histology in the resection specimen (P < .0001) but not in the biopsy (P = .09). CONCLUSIONS: In contrast to epithelioid histology, sarcomatoid histology in biopsies is highly accurate. Despite intratumoral heterogeneity, the accuracy of histologic classification increases with the number of tissue blocks examined, emphasizing the diagnostic value of extensive sampling by presurgery biopsies.

Integrated genomic analysis of recurrence-associated small non-coding RNAs in oesophageal cancer.

OBJECTIVE: Oesophageal squamous cell carcinoma (ESCC) is a heterogeneous disease with variable outcomes that are challenging to predict. A better understanding of the biology of ESCC recurrence is needed to improve patient care. Our goal was to identify small non-coding RNAs (sncRNAs) that could predict the likelihood of recurrence after surgical resection and to uncover potential molecular mechanisms that dictate clinical heterogeneity. DESIGN: We developed a robust prediction model for recurrence based on the analysis of the expression profile data of sncRNAs from 108 fresh frozen ESCC specimens as a discovery set and assessment of the associations between sncRNAs and recurrence-free survival (RFS). We also evaluated the mechanistic and therapeutic implications of sncRNA obtained through integrated analysis from multiple datasets. RESULTS: We developed a risk assessment score (RAS) for recurrence with three sncRNAs (microRNA (miR)-223, miR-1269a and nc886) whose expression was significantly associated with RFS in the discovery cohort (n=108). RAS was validated in an independent cohort of 512 patients. In multivariable analysis, RAS was an independent predictor of recurrence (HR, 2.27; 95% CI, 1.26 to 4.09; p=0.007). This signature implies the expression of ΔNp63 and multiple alterations of driver genes like PIK3CA. We suggested therapeutic potentials of immune checkpoint inhibitors in low-risk patients, and Polo-like kinase inhibitors, mammalian target of rapamycin (mTOR) inhibitors, and histone deacetylase inhibitors in high-risk patients. CONCLUSION: We developed an easy-to-use prognostic model with three sncRNAs as robust prognostic markers for postoperative recurrence of ESCC. We anticipate that such a stratified and systematic, tumour-specific biological approach will potentially contribute to significant improvement in ESCC treatment.

Utility of Adjuvant Chemotherapy After Neoadjuvant Chemoradiation and Esophagectomy for Esophageal Cancer.

OBJECTIVE: To determine whether adjuvant chemotherapy (AC) after neoadjuvant chemoradiation and esophagectomy is associated with improved overall survival for patients with locally advanced esophageal cancer, and to evaluate how pathologic disease response to neoadjuvant treatment impacts this effect. BACKGROUND: Neoadjuvant chemoradiation is currently the preferred management approach for locoregional esophageal cancer. Although there is interest in the use of AC, the benefit of systemic therapy after neoadjuvant chemoradiation and esophagectomy is unclear. METHODS: Retrospective cohort study of patients with esophageal cancer treated with neoadjuvant chemoradiation and esophagectomy in the National Cancer Data Base (2006-2012). RESULTS: Among 3592 patients with esophageal cancer (84.7% adenocarcinoma, 15.2% squamous cell carcinoma), 335 (9.3%) were treated with AC. AC was not associated with a significantly lower risk of death among patients with no residual disease (ypT0N0) or residual non-nodal disease (ypT+N0). Among patients with residual nodal disease (ypTanyN+), AC was associated with a 30% lower risk of death in the overall cohort [hazard ratio (HR) 0.70, (0.57-0.85)] and among those with adenocarcinoma [HR 0.69 (0.57-0.85)]. Using a 90-day postoperative landmark, findings were similar. Among patients with postoperative length of stay ≤10 days and no unplanned readmission, AC was associated with approximately 40% lower risk of death among patients with residual nodal disease [overall cohort, HR 0.63 (0.48-0.84); adenocarcinoma, HR 0.66 (0.49-0.88)]. CONCLUSIONS: AC after neoadjuvant chemoradiation and esophagectomy is associated with improved survival in patients with residual nodal disease. Our findings suggest AC may provide additional benefit for esophageal cancer patients, and merits further investigation.

Minimally invasive esophagectomy: results of a prospective phase II multicenter trial-the eastern cooperative oncology group (E2202) study.

OBJECTIVE: The primary aim of this trial was to assess the feasibility of minimally invasive esophagectomy (MIE) in a multi-institutional setting. BACKGROUND: Esophagectomy is an important, potentially curative treatment for localized esophageal cancer, but is a complex operation. MIE may decrease the morbidity and mortality of resection, and single-institution studies have demonstrated successful outcomes with MIE. METHODS: We conducted a multicenter, phase II, prospective, cooperative group study (coordinated by the Eastern Cooperative Oncology Group) to evaluate the feasibility of MIE. Patients with biopsy-proven high-grade dysplasia or esophageal cancer were enrolled at 17 credentialed sites. Protocol surgery consisted of either 3-stage MIE or Ivor Lewis MIE. The primary end point was 30-day mortality. Secondary end points included adverse events, duration of hospital-stay, and 3-year outcomes. RESULTS: Protocol surgery was completed in 95 of the 104 patients eligible for the primary analysis (91.3%). The 30-day mortality in eligible patients who underwent MIE was 2.1%; perioperative mortality in all registered patients eligible for primary analysis was 2.9%. Median intensive care unit and hospital stay were 2 and 9 days, respectively. Grade 3 or higher adverse events included anastomotic leak (8.6%), acute respiratory distress syndrome (5.7%), pneumonitis (3.8%), and atrial fibrillation (2.9%). At a median follow-up of 35.8 months, the estimated 3-year overall survival was 58.4% (95% confidence interval: 47.7%-67.6%). Locoregional recurrence occurred in only 7 patients (6.7%). CONCLUSIONS: This prospective multicenter study demonstrated that MIE is feasible and safe with low perioperative morbidity and mortality and good oncological results. This approach can be adopted by other centers with appropriate expertise in open esophagectomy and minimally invasive surgery.

Safety and efficacy of radiation dose delivered via iodine-125 brachytherapy mesh implantation for deep cavity sarcomas.

BACKGROUND: Radiation delivered as brachytherapy (BRT) via catheters placed during extremity soft tissue sarcoma (STS) resection results in acceptable local control rates; however, there are limitations in deep cavities. (125)I seeds embedded in mesh provide a flexible BRT platform that may be contoured to irregular deep cavities surfaces, but the risks and benefits are unknown. METHODS: Patients with thoracic, abdominal, pelvic, retroperitoneal, and deep truncal STS undergoing resection and implantation of permanent (125)I mesh BRT at our institution were reviewed. Local recurrence rates within the tumor bed covered by mesh (in field) and postoperative complications were analyzed. RESULTS: Between 2000 and 2010, a total of 46 patients were treated for primary (n = 8, 17 %) or recurrent (n = 38, 83 %) deep cavity STS (median follow-up 34.8 months); 74 % received external-beam radiotherapy for this or a prior presentation. In-field recurrences were observed in 9 patients (19.5 %). Crude cumulative incidences of in-field, regional, and distant recurrences at 5 years were 26.3, 54.2, and 54.1 %, respectively. 5-year overall survival rate was 47.2 %; median survival was 44.0 months. Twenty-two patients (48 %) experienced complications, half of whom (24 %) developed grade III/IV complications requiring percutaneous intervention (n = 6) or reoperation (n = 5) at a median of 35.5 days. There were no postoperative deaths. CONCLUSIONS: To our knowledge, this is the first study to report safety and efficacy for permanent (125)I mesh BRT implantation after resection of deep cavity STS. Local in-field recurrence rates were relatively low in this high-risk population. However, 24 % developed complications requiring intervention. (125)I mesh BRT appears effective, but it should be used with caution.

Extrapleural pneumonectomy in the treatment of epithelioid malignant pleural mesothelioma: novel prognostic implications of combined N1 and N2 nodal involvement based on experience in 529 patients.

OBJECTIVE: We review our 24-year experience with extrapleural pneumonectomy (EPP) in the treatment of epithelioid malignant pleural mesothelioma (MPM). BACKGROUND: Recent publications, particularly the MARS (Mesothelioma and Radical Surgery) feasibility study by Treasure et al, have questioned the safety and efficacy of EPP for MPM. METHODS: An institutional review board-approved, prospective, single-center database was retrospectively reviewed. Descriptive statistics and Kaplan-Meier analysis of overall survival are reported. RESULTS: From 1988 to 2011, a total of 529 patients with epithelioid MPM underwent complete resection by EPP as part of a multimodality strategy. Among these, 131 (25%) were women, and the median age was 59 (range, 17-79) years. Median postoperative hospital stay was 10 (range, 1-101) days. Twenty-six patients (5%) experienced 30-day or in-hospital mortality. Median overall survival was 18 months, with 1-, 3-, 5-, and 10-year survival rates of 67%, 28%, 14%, and 4%, respectively. Outcome by pathologic lymph node status (N, median overall survival) was N0: 224, 26 months; N1: 118, 17 months; N2: 181, 13 months; N3: 5, 7 months; Nx: 1, not evaluable. CONCLUSIONS: EPP has evolved as an effective method for macroscopic complete resection. This study confirms that lymph node status is significantly correlated with overall survival in patients with epithelioid MPM undergoing EPP and suggests that those with simultaneous involvement of N1 and N2 stations are at increased risk. This observation underscores the need for thorough staging of both N1 and N2 stations and has implications for revision of MPM staging criteria.

Clinical application of pharmacokinetic analysis as a biomarker of solitary pulmonary nodules: dynamic contrast-enhanced MR imaging.

The purpose of this study is to evaluate perfusion indices and pharmacokinetic parameters in solitary pulmonary nodules (SPNs). Thirty patients of 34 enrolled with SPNs (15-30 mm) were evaluated in this study. T1 and T2-weighted structural images and 2D turbo FLASH perfusion images were acquired with shallow free breathing. B-spline nonrigid image registration and optimization by χ² test against pharmacokinetic model curve were performed on dynamic contrast-enhanced MRI. This allowed voxel-by-voxel calculation of k(ep) , the rate constant for tracer transport to and from plasma and the extravascular extracellular space. Mean transit time, time-to-peak, initial slope, and maximum enhancement (E(max) ) were calculated from time-intensity curves fitted to a gamma variate function. After blinded data analysis, correlation with tissue histology from surgical resection or biopsy samples was performed. Histologic evaluation revealed 25 malignant and five benign SPNs. All benign SPNs had k(ep) < 1.0 min⁻¹. Nineteen of 25 (76%) malignant SPNs showed k(ep) > 1.0 min⁻¹. Sensitivity to diagnose malignant SPNs at a cutoff of k(ep) = 1.0 min⁻¹ was 76%, specificity was 100%, positive predictive value was 100%, negative predictive value was 45%, and accuracy was 80%. Of all indices studied, k(ep) was the most significant in differentiating malignant from benign SPNs.

Epithelial malignant pleural mesothelioma after extrapleural pneumonectomy: stratification of survival with CT-derived tumor volume.

OBJECTIVE: The purpose of this study was to assess the usefulness of CT-derived tumor volume, with control for other prognostic factors, for stratifying survival after surgery-based multimodality treatment of a large cohort of patients with epithelial malignant pleural mesothelioma. MATERIALS AND METHODS: We retrospectively reviewed 338 patients with mesothelioma who underwent extrapleural pneumonectomy between 2001 and 2007. The study cohort comprised 88 patients with epithelial subtype tumors, DICOM-format CT scans, and data regarding neoadjuvant and adjuvant therapy. Tumor volume was calculated, and Kaplan-Meier survival and Cox regression analyses were performed to compare the estimated survival functions of patient subgroups based on volume and other covariates related to outcome (sex, age, preoperative platelet count, hemoglobin concentration, WBC count, clinical and pathologic TNM category, and administration of neoadjuvant and adjuvant therapy). A multivariate regression model was derived on the basis of the most significant univariate predictors. RESULTS: The median estimated tumor volume was 319 cm(3) (range, 4-3256 cm(3)). In univariate analysis, tumor volume, hemoglobin concentration, platelet count, pathologic TNM category, and administration of adjuvant chemotherapy or radiation therapy met the criteria for inclusion in the reverse stepwise regression analysis. In the final model, tumor volume, hemoglobin concentration, and administration of adjuvant chemotherapy or radiotherapy were identified as independently associated with overall survival. CONCLUSION: With control of prognostic covariates, CT-derived tumor volume can be used to stratify survival of patients with epithelial mesothelioma after extrapleural pneumonectomy and should be included in prognostic evaluation of patients for whom resection is being considered.

Aging and environmental exposures alter tissue-specific DNA methylation dependent upon CpG island context.

Epigenetic control of gene transcription is critical for normal human development and cellular differentiation. While alterations of epigenetic marks such as DNA methylation have been linked to cancers and many other human diseases, interindividual epigenetic variations in normal tissues due to aging, environmental factors, or innate susceptibility are poorly characterized. The plasticity, tissue-specific nature, and variability of gene expression are related to epigenomic states that vary across individuals. Thus, population-based investigations are needed to further our understanding of the fundamental dynamics of normal individual epigenomes. We analyzed 217 non-pathologic human tissues from 10 anatomic sites at 1,413 autosomal CpG loci associated with 773 genes to investigate tissue-specific differences in DNA methylation and to discern how aging and exposures contribute to normal variation in methylation. Methylation profile classes derived from unsupervised modeling were significantly associated with age (P<0.0001) and were significant predictors of tissue origin (P<0.0001). In solid tissues (n = 119) we found striking, highly significant CpG island-dependent correlations between age and methylation; loci in CpG islands gained methylation with age, loci not in CpG islands lost methylation with age (P<0.001), and this pattern was consistent across tissues and in an analysis of blood-derived DNA. Our data clearly demonstrate age- and exposure-related differences in tissue-specific methylation and significant age-associated methylation patterns which are CpG island context-dependent. This work provides novel insight into the role of aging and the environment in susceptibility to diseases such as cancer and critically informs the field of epigenomics by providing evidence of epigenetic dysregulation by age-related methylation alterations. Collectively we reveal key issues to consider both in the construction of reference and disease-related epigenomes and in the interpretation of potentially pathologically important alterations.

Circulating and tumor-infiltrating myeloid cells predict survival in human pleural mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) tumor cells produce copious amounts of myeloid cell-stimulating factors. The current study examined the prognostic significance of circulating monocytes and tumor-infiltrating macrophages on overall survival in patients with MPM. METHODS: The authors retrospectively reviewed 667 patients with MPM who underwent cytoreductive surgery at the Brigham and Women's Hospital in Boston, Massachusetts between 1989 and 2009. Kaplan-Meier and Cox proportional hazards models were used to determine the impact of preoperative circulating monocytes on overall survival. Immunohistochemical staining for CD68 was performed on a tissue microarray of MPM tumors from 52 patients undergoing cytoreductive surgery. The phenotype of circulating monocytes and tumor-infiltrating macrophages in 7 additional patients was determined by flow cytometry. RESULTS: The median survival for all patients was 13.4 months, and 35% of patients had tumors of nonepithelial histology. For patients with nonepithelial compared with epithelial tumors, survival was significantly worse (9.3 months vs 16.6 months; P < .0001), the number of monocytes was significantly higher (580 ± 20 cells/µL vs 520 ± 10 cells/µL; P = .002), and higher monocyte counts were associated with higher tumor stage. Increasing monocyte counts were correlated with poor survival for all patients with MPM. Within MPM tumors, macrophages comprised 27% ± 9% of the tumor area and demonstrated an immunosuppressive phenotype with high expression of CD163, CD206, and interleukin-4 receptor α. The degree of macrophage infiltration was found to be negatively correlated with survival in patients with nonepithelial (P = .008) but not those with epithelial (P = .7) MPM, independent of disease stage. CONCLUSIONS: Higher numbers of circulating monocytes are associated with poor survival in all patients with MPM and higher densities of tumor-infiltrating macrophages are associated with poor survival in patients with nonepithelial MPM. Both may enable a novel target for immunotherapy.

Semi-supervised recursively partitioned mixture models for identifying cancer subtypes.

MOTIVATION: Patients with identical cancer diagnoses often progress differently. The disparity we see in disease progression and treatment response can be attributed to the idea that two histologically similar cancers may be completely different diseases on the molecular level. Methods for identifying cancer subtypes associated with patient survival have the capacity to be powerful instruments for understanding the biochemical processes that underlie disease progression as well as providing an initial step toward more personalized therapy for cancer patients. We propose a method called semi-supervised recursively partitioned mixture models (SS-RPMM) that utilizes array-based genetic and patient-level clinical data for finding cancer subtypes that are associated with patient survival. RESULTS: In the proposed SS-RPMM, cancer subtypes are identified using a selected subset of genes that are associated with survival time. Since survival information is used in the gene selection step, this method is semi-supervised. Unlike other semi-supervised clustering classification methods, SS-RPMM does not require specification of the number of cancer subtypes, which is often unknown. In a simulation study, our proposed method compared favorably with other competing semi-supervised methods, including: semi-supervised clustering and supervised principal components analysis. Furthermore, an analysis of mesothelioma cancer data using SS-RPMM, revealed at least two distinct methylation profiles that are informative for survival. AVAILABILITY: The analyses implemented in this article were carried out using R (http://www.r.project.org/). CONTACT: devin_koestler@brown.edu; e_andres_houseman@brown.edu SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

FDG PET/CT patterns of treatment failure of malignant pleural mesothelioma: relationship to histologic type, treatment algorithm, and survival.

PURPOSE: This study investigated the diagnostic performance and prognostic value of fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT in suspected malignant pleural mesothelioma (MPM) recurrence, in the context of patterns and intensity of FDG uptake, histologic type, and treatment algorithm. METHODS: Fifty patients with MPM underwent FDG PET/CT for restaging 11 ± 6 months after therapy. Tumor relapse was confirmed by histopathology, and by clinical evolution and subsequent imaging. Progression-free survival was defined as the time between treatment and the earliest clinical evidence of recurrence. Survival after FDG PET/CT was defined as the time between the scan and death or last follow-up. Overall survival was defined as the time between initial treatment and death or last follow-up date. RESULTS: Treatment failure was confirmed in 42 patients (30 epithelial and 12 non-epithelial MPM). Sensitivity, specificity, accuracy, negative predictive value, and positive predictive value for FDG PET/CT were 97.6, 75, 94, 86, and 95.3%, respectively. FDG PET/CT evidence of single site of recurrence was observed in the ipsilateral hemithorax in 18 patients (44%), contralaterally in 2 (5%), and in the abdomen in 1 patient (2%). Bilateral thoracic relapse was detected in three patients (7%). Simultaneous recurrence in the ipsilateral hemithorax and abdomen was observed in ten (24%) patients and in seven (17%) in all three cavities. Unsuspected distant metastases were detected in 11 patients (26%). Four patterns of uptake were observed in recurrent disease: focal, linear, mixed (focal/linear), and encasing, with a significant difference between the intensity of uptake in malignant lesions compared to benign post-therapeutic changes. Lesion uptake was lower in patients previously treated with more aggressive therapy and higher in intrathoracic lesions of patients with distant metastases. FDG PET/CT helped in the selection of 12 patients (29%) who benefited from additional previously unplanned treatment at the time of failure. Multivariate analysis showed that histologic type remained the only independent predictor of progression-free survival. Survival after relapse was independently predicted by the pattern of FDG uptake and PET nodal status, and overall survival by the maximum standard uptake value. CONCLUSION: FDG PET/CT is an accurate modality to diagnose and to estimate the extent of locoregional and distant MPM recurrence, and it carries independent prognostic value. Once the disease recurs, survival outcomes seem to be independent of histologic type and highly dependent on the intensity of lesion uptake and on the pattern of metabolically active disease in FDG PET/CT. Our observations should be considered limited to patients treated surgically with or without perioperative therapies and should not be extrapolated to those unresectable cases treated with chemotherapy alone.

Genes associated with prognosis after surgery for malignant pleural mesothelioma promote tumor cell survival in vitro.

BACKGROUND: Mesothelioma is an aggressive neoplasm with few effective treatments, one being cytoreductive surgery. We previously described a test, based on differential expression levels of four genes, to predict clinical outcome in prospectively consented mesothelioma patients after surgery. In this study, we determined whether any of these four genes could be linked to a cancer relevant phenotype. METHODS: We conducted a high-throughput RNA inhibition screen to knockdown gene expression levels of the four genes comprising the test (ARHGDIA, COBLL1, PKM2, TM4SF1) in both a human lung-derived normal and a tumor cell line using three different small inhibitory RNA molecules per gene. Successful knockdown was confirmed using quantitative RT-PCR. Detection of statistically significant changes in apoptosis and mitosis was performed using immunological assays and quantified using video-assisted microscopy at a single time-point. Changes in nuclear shape, size, and numbers were used to provide additional support of initial findings. Each experiment was conducted in triplicate. Specificity was assured by requiring that at least 2 different siRNAs produced the observed change in each cell line/time-point/gene/assay combination. RESULTS: Knockdown of ARHGDIA, COBLL1, and TM4SF1 resulted in 2- to 4-fold increased levels of apoptosis in normal cells (ARHGDIA only) and tumor cells (all three genes). No statistically significant changes were observed in apoptosis after knockdown of PKM2 or for mitosis after knockdown of any gene. CONCLUSIONS: We provide evidence that ARHGDIA, COBLL1, and TM4SF1 are negative regulators of apoptosis in cultured tumor cells. These genes, and their related intracellular signaling pathways, may represent potential therapeutic targets in mesothelioma.

Impact of nonrigid motion correction technique on pixel-wise pharmacokinetic analysis of free-breathing pulmonary dynamic contrast-enhanced MR imaging.

PURPOSE: To investigates the impact of nonrigid motion correction on pixel-wise pharmacokinetic analysis of free-breathing DCE-MRI in patients with solitary pulmonary nodules (SPNs). Misalignment of focal lesions due to respiratory motion in free-breathing dynamic contrast-enhanced MRI (DCE-MRI) precludes obtaining reliable time-intensity curves, which are crucial for pharmacokinetic analysis for tissue characterization. MATERIALS AND METHODS: Single-slice 2D DCE-MRI was obtained in 15 patients. Misalignments of SPNs were corrected using nonrigid B-spline image registration. Pixel-wise pharmacokinetic parameters K(trans) , v(e) , and k(ep) were estimated from both original and motion-corrected DCE-MRI by fitting the two-compartment pharmacokinetic model to the time-intensity curve obtained in each pixel. The "goodness-of-fit" was tested with χ(2) -test in pixel-by-pixel basis to evaluate the reliability of the parameters. The percentages of reliable pixels within the SPNs were compared between the original and motion-corrected DCE-MRI. In addition, the parameters obtained from benign and malignant SPNs were compared. RESULTS: The percentage of reliable pixels in the motion-corrected DCE-MRI was significantly larger than the original DCE-MRI (P = 4 × 10(-7) ). Both K(trans) and k(ep) derived from the motion-corrected DCE-MRI showed significant differences between benign and malignant SPNs (P = 0.024, 0.015). CONCLUSION: The study demonstrated the impact of nonrigid motion correction technique on pixel-wise pharmacokinetic analysis of free-breathing DCE-MRI in SPNs.

Transcriptome sequencing of malignant pleural mesothelioma tumors.

Cancers arise by the gradual accumulation of mutations in multiple genes. We now use shotgun pyrosequencing to characterize RNA mutations and expression levels unique to malignant pleural mesotheliomas (MPMs) and not present in control tissues. On average, 266 Mb of cDNA were sequenced from each of four MPMs, from a control pulmonary adenocarcinoma (ADCA), and from normal lung tissue. Previously observed differences in MPM RNA expression levels were confirmed. Point mutations were identified by using criteria that require the presence of the mutation in at least four reads and in both cDNA strands and the absence of the mutation from sequence databases, normal adjacent tissues, and other controls. In the four MPMs, 15 nonsynonymous mutations were discovered: 7 were point mutations, 3 were deletions, 4 were exclusively expressed as a consequence of imputed epigenetic silencing, and 1 was putatively expressed as a consequence of RNA editing. Notably, each MPM had a different mutation profile, and no mutated gene was previously implicated in MPM. Of the seven point mutations, three were observed in at least one tumor from 49 other MPM patients. The mutations were in genes that could be causally related to cancer and included XRCC6, PDZK1IP1, ACTR1A, and AVEN.

Diagnostic Laparoscopy Improves Staging of Malignant Pleural Mesothelioma With Routine Positron Emission Tomography Imaging.

BACKGROUND: With a multimodal treatment strategy, cytoreductive surgery extends survival in malignant pleural mesothelioma. Improving the accuracy of staging can refine patient selection. Our objective was to determine whether diagnostic laparoscopy (DL) improves staging for patients with malignant pleural mesothelioma with the routine use of positron emission tomography (PET). METHODS: We performed a retrospective review of our prospectively maintained database from February 2014 to May 2019. Inclusion criteria were patients who had disease in the chest that was deemed potentially resectable by radiographic criteria and who underwent DL as part of the staging evaluation before surgery. RESULTS: Of 187 patients (71% men, 80% epithelial) who underwent DL during staging, 76% proceeded to surgery; 22% were unresectable at exploratory thoracotomy and 78% underwent resection (pleurectomy and decortication, 68%; extrapleural pneumonectomy, 32%). Also, 89% had a PET computed tomography (CT), and 11% had a preoperative CT without PET. DL revealed peritoneal disease in 17%. Among patients with pathologically proven disease at DL, 77% had negative PET-CT imaging. Based on the pathologic findings at DL the sensitivity, specificity, positive predictive value, and negative predictive value of PET-CT were 23%, 78%, 17%, and 83%, respectively. The accuracy of PET-CT was 68%. CONCLUSIONS: PET-CT has low sensitivity and diagnostic accuracy to identify peritoneal disease in malignant pleural mesothelioma. DL as part of the preoperative staging defines an important subset of patients with bicavitary disease. We recommend DL as a component of staging before surgery.