Comparison of genomic abnormality in malignant mesothelioma by the site of origin

Comprehensive genomic profiling of pediatric peritoneal mesothelioma: case report with a literature review

Malignant peritoneal mesothelioma is an extremely rare and poorly recognized neoplasm in children. A 5-year-old boy presented with a 1-year history of progressive painless abdominal distension. A CT revealed a 19 × 19 × 11 cm3 cystic mass in the right hemiabdomen, without infiltrating the surrounding structures. The tumor was completely removed by surgery. The microscopic and immunohistochemical analyses confirmed peritoneal mesothelioma. Comprehensive genomic profiling revealed no major driving mutations including BAP1, no fusions, but with amplifications of AURKA, AURKC, HLA-1B, ZNF-217, OR5F1 and MEN1 genes. Imaging follow-up 3 months after surgery revealed metastatic disease. The patient died of pneumonia at another hospital shortly after the last follow-up examination at our institution. Pediatric peritoneal mesothelioma is an extremely rare malignancy with limited targeted options and a poor prognosis. Some of the identified molecular genomic biomarkers require further exploration and validation in this cancer.

Aurora Kinase A as a Diagnostic and Prognostic Marker of Malignant Mesothelioma

Background

Malignant mesothelioma (MM) is a highly aggressive cancer with a poor prognosis. Despite the use of several well-known markers, the diagnosis of MM is still challenging in some cases. we applied bioinformatics to identify key genes and screen for diagnostic and prognostic markers of MM.

Methods

The expression profiles of GSE2549 and GSE112154 microarray datasets from the Gene Expression Omnibus database contained 87 cases of MM tissue and 8 cases of normal mesothelial tissue in total. The GEO2R tool was used to detect differentially expressed genes (DEGs). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of DEGs were performed using DAVID Bioinformatics Resources. The DEGs protein-protein interaction networks were constructed from the STRING database. Cytoscape was used to identify significant modules and hub genes. The GEPIA database was used to explore relationships between hub genes and prognosis of MM. Immunohistochemistry was used to analyze protein expression in tissue microarrays with 47 Chinese MM tissues. Statistical analyses diagnostic and prognostic values.

Results

346 DEGs were identified: 111 genes upregulated, and 235 downregulated. GO analysis showed that the primary biological processes of these DEGs were cell adhesion, leukocyte migration, and angiogenesis. The main cellular components included the extracellular space, extracellular exosome, and extracellular region. The molecular functions were integrin binding, heparin binding, and calcium ion binding. KEGG pathway analysis showed that DEGs are primarily involved in PPAR signaling pathway, extracellular matrix–receptor interactions, and regulation of lipolysis in adipocytes. Survival analysis showed that seven genes—AURKA, GAPDH, TOP2A, PPARG, SCD, FABP4, and CEBPA—may be potential prognostic markers for MM. Immunohistochemical studies showed that Aurora kinase A (AURKA gene encode, Aurora-A) and GAPDH were highly expressed in MM tissue in comparison with normal mesothelial tissue. Kaplan-Meier analysis confirmed a correlation between Aurora-A protein expression and overall survival but did not confirm a correlation with GAPDH. The receiver operating characteristic curves of Aurora-A protein expression suggested acceptable accuracy (AUC = 0.827; 95% CI [0.6686 to 0.9535]; p = 0.04). The sensitivity and specificity of Aurora-A were 83.33% and 77.78%, respectively.

Conclusion

Aurora-A could be an optimal diagnostic biomarker and a potential prognostic marker for MM.

New Immunotherapy Combinations Enter the Battlefield of Malignant Mesothelioma

Chimeric antigen receptor (CAR) T cells targeting mesothelin plus pembrolizumab, and atezolizumab plus bevacizumab, have recently shown clinical efficacy in phase I trials in malignant pleural and peritoneal mesothelioma. Despite being tested in a highly selected patient population and requiring a complex engineering that can hardly be upscaled, CAR T cells combined with pembrolizumab bring the first proof of efficacy in cold solid tumors with low genomic heterogeneity, while atezolizumab-bevacizumab offers an easy-to-use combination of antiangiogenics and immunotherapy in an orphan disease.See related article by Raghav et al., p. 2738.See related article by Adusumilli et al., p. 2748.

Efficacy, Safety and Biomarker Analysis of Combined PD-L1 (Atezolizumab) and VEGF (Bevacizumab) Blockade in Advanced Malignant Peritoneal Mesothelioma

Malignant peritoneal mesothelioma (MPeM) is a rare but aggressive malignancy with limited treatment options. VEGF inhibition enhances efficacy of immune-checkpoint inhibitors by reworking the immunosuppressive tumor milieu. Efficacy and safety of combined PD-L1 (atezolizumab) and VEGF (bevacizumab) blockade (AtezoBev) was assessed in 20 patients with advanced and unresectable MPeM with progression or intolerance to prior platinum-pemetrexed chemotherapy. The primary endpoint of confirmed objective response rate per RECISTv1.1 by independent radiology review was 40% (8/20; 95%CI:19.1-64.0) with median response duration of 12.8 months. Six (75%) responses lasted for >10 months. Progression-free and overall survival at 1-year were 61% (95%CI:35-80) and 85% (95%CI:60-95), respectively. Responses occurred notwithstanding low tumor mutation burden and PD-L1 expression status. Baseline epithelial-mesenchymal transition gene-expression correlated with therapeutic resistance/response (r=0.80; P=0.0010). AtezoBev showed promising and durable efficacy in patients with advanced MPeM with acceptable safety profile and these results address a grave unmet need for this orphan disease.

Do TRIB1 and IL-9 Gene Polymorphisms Impact the Development and Manifestation of Pituitary Adenoma?

BACKGROUND/AIM

To evaluate the association between TRIB1(rs6987702) and IL-9(rs1859430, rs2069870) genotypes with the development and manifestation of pituitary adenoma (PA).

MATERIALS AND METHODS

The study group included 141 patients with PA and the control group consisted of 287 healthy people. The genotyping of rs6987702, rs1859430 and rs2069870 was carried out using a real-time polymerase chain reaction.

RESULTS

Statistically significant results were obtained regarding the rs1859430, but there were no significant results regarding rs6987702. We found that the rs1859430 A/A genotype increased the odds of having recurrent PA six times (p=0.006) under the co-dominant model and four times (p=0.021) under the recessive model. Furthermore, the analysis showed that the G/A genotype increased the odds of having recurrent PA 2.3 times (p=0.003) under the co-dominant model, while G/A and A/A genotypes increased the odds 2.7 times (p=0.011) under the over-dominant model.

CONCLUSION

Certain genotypes of rs1859430 can be associated with PA recurrence.

Efficacy of second-line treatment and prognostic factors in patients with advanced malignant peritoneal mesothelioma: a retrospective study

Background

Standard treatment for malignant peritoneal mesothelioma has not been established, and systemic chemotherapy is administered according to malignant pleural mesothelioma. We previously reported the efficacy of cisplatin plus pemetrexed as first-line chemotherapy; however, the efficacy of second-line chemotherapy remains unknown.

Methods

We retrospectively evaluated patients with malignant peritoneal mesothelioma who started first-line systemic chemotherapy with platinum plus pemetrexed between March 2007 and February 2019 at the National Cancer Center Hospital. Patients who received second-line chemotherapy after failure of platinum plus pemetrexed were identified. We evaluated the efficacy of first- and second-line chemotherapy, and explored the prognostic factors. Survival outcomes were estimated using the Kaplan–Meier method, and between-group differences were compared using the log-rank test. Univariate and multivariate analyses were performed using Cox proportional hazards models.

Results

A total of 54 and 26 patients received platinum plus pemetrexed as first- and second-line chemotherapy, respectively (gemcitabine in 12 patients; taxane, six; nivolumab, three; and others, five). In all patients, the median overall survival and progression-free survival after first-line chemotherapy were 16.6 and 7.3 months, respectively. Among patients who received second-line chemotherapy, the median overall survival, progression-free survival, and second-line overall survival were 16.9, 3.2, and 9.9 months, respectively. Patients who received ≥6 cycles of platinum plus pemetrexed as first-line chemotherapy had longer overall survival after second-line chemotherapy than those who did not (hazard ratio, 0.23; 95% confidence interval: 0.06–0.82; p = 0.02).

Conclusions

Second-line chemotherapy may be an option for refractory malignant peritoneal mesothelioma, especially in patients who have completed 6 cycles of platinum plus pemetrexed as first-line chemotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08025-x.

Fluorescence in situ hybridization (FISH) provides estimates of minute and interstitial BAP1, CDKN2A, and NF2 gene deletions in peritoneal mesothelioma

The aim of this study was to assess the performance of fluorescence in situ hybridization (FISH) in identifying the copy number profiles of the three key peritoneal mesothelioma tumor suppressor genes BAP1, CDKN2A, and NF2, with particular emphasis on minute homozygous deletions, a copy number abnormality recently unveiled at the 3p21 (BAP1) chromosomal region using high-throughput methods. FISH was performed on 75 formalin-fixed-paraffin-embedded peritoneal mesotheliomas and recognized two types of monoallelic loss (monosomy, and hemizygous deletion) and two types of biallelic loss (canonical homozygous deletion with a complete loss of FISH signal and homozygous deletion with diminished signal). Diminished FISH signals revealed deletions occurring within the genomic region covered by the gene-specific probe and affected all three tumor suppressors. BAP1 homozygous deletions with diminished signal outnumbered canonical homozygous deletions (13 vs 3): conversely, canonical homozygous deletions were prevalent for CDKN2A (2 vs 14). Diminished signal homozygous deletion was the only pattern of biallelic loss observed for NF2 (2 cases). Hemizygous deletion mainly affected BAP1 (21 vs 6), while monosomy was prevalent for CDKN2A (14 vs 7) and particularly for NF2 where it accounts for all monoallelic losses. FISH/immunohistochemistry (BAP1, CDKN2A, and MTAP) correlation showed that all homozygous deletions, including those with diminished signals, resulted in a null BAP1 and CDKN2A immunophenotype but only canonical CDKN2A homozygous deletions resulted in MTAP loss of expression. BAP1 hemizygous deletion, but not monosomy, was also invariably associated with loss of protein expression whereas neither type of CDKN2A monoallelic loss correlated with p16 or MTAP immunohistochemistry. Array comparative genomic hybridization performed on a spontaneously emerging peritoneal mesothelioma cell line provided support for the interpretation of the FISH patterns and allowed us to extend the number of chromatin remodeling factors involved in mesothelioma to SETD7 and PCGF5, two previously unreported genes.

Splicing modulation as novel therapeutic strategy against diffuse malignant peritoneal mesothelioma

Introduction

Therapeutic options for diffuse malignant peritoneal mesothelioma (DMPM) are limited to surgery and locoregional chemotherapy. Despite improvements in survival rates, patients eventually succumb to disease progression. We investigated splicing deregulation both as molecular prognostic factor and potential novel target in DMPM, while we tested modulators of SF3b complex for antitumor activity.

Methods

Tissue-microarrays of 64 DMPM specimens were subjected to immunohistochemical assessment of SF3B1 expression and correlation to clinical outcome. Two primary cell cultures were used for gene expression profiling and in vitro screening of SF3b modulators. Drug-induced splicing alterations affecting downstream cellular pathways were detected through RNA sequencing. Ultimately, we established bioluminescent orthotopic mouse models to test the efficacy of splicing modulation in vivo.

Results

Spliceosomal genes are differentially upregulated in DMPM cells compared to normal tissues and high expression of SF3B1 correlated with poor clinical outcome in univariate and multivariate analysis. SF3b modulators (Pladienolide-B, E7107, Meayamycin-B) showed potent cytotoxic activity in vitro with IC50 values in the low nanomolar range. Differential splicing analysis of Pladienolide-B-treated cells revealed abundant alterations of transcripts involved in cell cycle, apoptosis and other oncogenic pathways. This was validated by RT-PCR and functional assays. E7107 demonstrated remarkable in vivo antitumor efficacy, with significant improvement of survival rates compared to vehicle-treated controls.

Conclusions

SF3B1 emerged as a novel potential prognostic factor in DMPM. Splicing modulators markedly impair cancer cell viability, resulting also in potent antitumor activity in vivo. Our data designate splicing as a promising therapeutic target in DMPM.

Malignant peritoneal mesothelioma: clinical aspects, and therapeutic perspectives

Malignant peritoneal mesothelioma (MPM) is a rare disease with a wide clinical spectrum. It arises from the peritoneal lining and commonly presents with diffuse, extensive spread throughout the abdomen and, more rarely, metastatic spread beyond the abdominal cavity. Computed tomography, magnetic resonance imaging and positron-emission tomography are important diagnostic tools used for the preoperative staging of MPM. The definitive diagnosis is based on histopathological analysis, mainly via immunohistochemistry. In this regard, paired-box gene 8 negativity represents a useful diagnostic biomarker for differentiating MPM from ovarian carcinoma. In addition, BRCA1-associated protein-1 (BAP1) loss is specific to MPM and allows it to be distinguished from both benign mesothelial lesions and ovarian serous tumors. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has become an increasingly important therapeutic approach, while systemic therapies are still being developed. Histology, Ki-67, completeness of cytoreduction, age, sex, and baseline thrombocytosis are commonly used to optimize patient selection for CRS with HIPEC. Additionally, it is well recognized that, compared to other subtypes, an epithelial morphology is associated with a favorable prognosis, whereas baseline thrombocytosis predicts an aggressive biologicalbehavior. Platelets and other immunologic cytokines have been evaluated as potential novel therapeutic targets. Epigenetic modifiers, including BAP1, SETD2 and DDX3X, are crucial in mesothelial tumorigenesis and provide opportunities for targeted treatment. Overexpression of the closely interacting phosphoinositide 3-kinase (PI3K) and the mammalian target of rapamycin (mTOR) pathways appears crucial in regulation of the malignant phenotype. The use of targeted therapies with PI3K-mTOR-based inhibitors requires further clinical assessment as a novel approach.

TRIB1 promotes colorectal cancer cell migration and invasion through activation MMP-2 via FAK/Src and ERK pathways

Colorectal cancer (CRC) is the third most common cancer in the world and distant metastasis is the leading cause of death among CRC patients. However, the underlying mechanisms of distant metastasis remain largely unknown. Amplification of 8q24 is a common chromosomal abnormality in CRC. In the present study, a putative oncogene at 8q24, TRIB1, was characterized for its role in CRC metastasis and underlying molecular mechanisms. Higher expression of TRIB1 protein was detected in 58/83 (69.9%) of CRC tissues, compared with adjacent non-tumor tissues. Moreover, the expression of TRIB1 was significantly associated with distant metastasis (P=0.043) and advanced staging (P=0.008) in CRC tissues. TRIB1 overexpression was also correlated with poor prognosis in CRC patients as analyzed in PrognoScan database. In addition, elevated expression of TRIB1 promoted CRC cell motility and adhesive ability, while silencing of TRIB1 reduced those effects. Further study revealed that TRIB1-mediated migration and invasion of CRC cells required up-regulation of MMP-2 through the activation of FAK/Src and ERK pathway. Collectively, the results suggest that TRIB1 promotes CRC cell motility by activation MMP-2 via the FAK/Src and ERK pathways. It may provide a potential diagnostic and therapeutic target for CRC.

[Mesothelioma]

Malignant mesotheliomas are rare and aggressive tumours arising from mesothelial cells of the pleura and peritoneum. Infrequent sites of origin are the pericardium and tunica vaginalis testis. More than 80% of mesotheliomas are localized in the pleura. Men are more frequently affected than women. The median age is >60 years. Asbestos exposure is the best known aetilogical risk factor and is reported in 54-90% of patients. In Germany, malignant mesotheliomas caused by occupational asbestos exposure are compensated as occupational disease since 1977. Several neoplastic and non-neoplastic lesions like metastasis, sarcomas, lymphomas or pleuritis with reactive mesothelial proliferation have to be distinguished from malignant mesotheliomas. Especially, the pathohistological differentiation between atypical reactive mesothelial proliferation from malignant mesothelioma is a diagnostic challenge.

Peritoneal Mesothelioma with Residential Asbestos Exposure. Report of a Case with Long Survival (Seventeen Years) Analyzed by Cgh-Array

Malignant mesothelioma is a rare and aggressive tumor with limited therapeutic options. We report a case of a malignant peritoneal mesothelioma (MPM) epithelioid type, with environmental asbestos exposure, in a 36-year-old man, with a long survival (17 years). The patient received standard treatment which included cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS AND RESULTS

Molecular analysis with comparative genomic hybridization (CGH)-array was performed on paraffin-embedded tumoral samples. Multiple chromosomal imbalances were detected. The gains were prevalent. Losses at 1q21, 2q11.1→q13, 8p23.1, 9p12→p11, 9q21.33→q33.1, 9q12→q21.33, and 17p12→p11.2 are observed. Chromosome band 3p21 (BAP1), 9p21 (CDKN2A) and 22q12 (NF2) are not affected. Conclusions: the defects observed in this case are uncommon in malignant peritoneal mesothelioma. Some chromosomal aberrations that appear to be random here, might actually be relevant events explaining the response to therapy, the long survival and, finally, may be considered useful prognostic factors in peritoneal malignant mesothelioma (PMM).

Genomic profiling of malignant peritoneal mesothelioma reveals recurrent alterations in epigenetic regulatory genes BAP1, SETD2, and DDX3X

Malignant mesothelioma is a rare cancer that arises from the mesothelial cells that line the pleural cavity and less commonly from the peritoneal lining of the abdomen and pelvis. Most pleural mesotheliomas arise in patients with a history of asbestos exposure, whereas the association of peritoneal mesotheliomas with exposure to asbestos and other potential carcinogens is less clear, suggesting that the genetic alterations that drive malignant peritoneal mesothelioma may be unique from those in pleural mesothelioma. Treatment options for all malignant mesotheliomas are currently limited, with no known targeted therapies available. To better understand the molecular pathogenesis of malignant peritoneal mesothelioma, we sequenced 510 cancer-related genes in 13 patients with malignant mesothelioma arising in the peritoneal cavity. The most frequent genetic alteration was biallelic inactivation of the BAP1 gene, which occurred in 9/13 cases, with an additional two cases demonstrating monoallelic loss of BAP1. All 11 of these cases demonstrated loss of BAP1 nuclear staining by immunohistochemistry, whereas two tumors without BAP1 alteration and all 42 cases of histologic mimics in peritoneum (8 multilocular peritoneal inclusion cyst, 6 well-differentiated papillary mesothelioma of the peritoneum, 16 adenomatoid tumor, and 12 low-grade serous carcinoma of the ovary) demonstrated intact BAP1 nuclear staining. Additional recurrently mutated genes in this cohort of malignant peritoneal mesotheliomas included NF2 (3/13), SETD2 (2/13), and DDX3X (2/13). While these genes are known to be recurrently mutated in pleural mesotheliomas, the frequencies are distinct in peritoneal mesotheliomas, with nearly 85% of peritoneal tumors harboring BAP1 alterations versus only 20-30% of pleural tumors. Together, these findings demonstrate the importance of epigenetic modifiers including BAP1, SETD2, and DDX3X in mesothelial tumorigenesis and suggest opportunities for targeted therapies.