Evaluation of prognostic histological parameters proposed for pleural mesothelioma in diffuse malignant peritoneal mesothelioma. A short report

An Evaluation Into the Robustness of Grading of Pleural Mesothelioma Outside of Specialist Centres

The 2021 WHO classification of thoracic tumours recommends grading pleural mesothelioma to aid prognostication. Robustness of grading and morphological characterisation is key to its clinical utility, though validation of this grading system has largely been conducted by expert thoracic pathologists. We conducted a survey inviting pathologists across a range of practices and expertise to grade digitised images of 50 epithelioid pleural mesotheliomas that had been graded by an expert in thoracic pathology. We included slides that were considered potentially problematic such as small biopsies, focal necrosis, and rare subtypes that may affect grading (small cell and deciduoid features). Using the Sectra Uniview web viewer, participants were asked to score atypia, mitotic count, and necrosis and choose from a list of cytological and architectural features. Seventy-four pathologists anonymously participated. There was 90% agreement of consensus scores with expert opinion using the WHO 2-tier grade and 72% for the 3-tier nuclear grade but only 70% for nuclear atypia, 56% for mitoses, and 84% for necrosis. Both 3-tier nuclear grade and WHO 2-tier grading systems were significantly associated with survival. Our study affirms the overall robustness and utility of grading for pleural mesothelioma, reveals variances, and suggests the need for dedicated training.

Analysis of TERT mRNA Levels and Clinicopathological Features in Patients with Peritoneal Mesothelioma

BACKGROUND/OBJECTIVES

Telomerase reverse transcriptase (TERT) is the catalytic subunit of the telomerase enzyme responsible for telomere length maintenance and is an important cancer hallmark. Our study aimed to clarify the mRNA expression of TERT in peritoneal mesothelioma (PeM), and to explore the relationship between its expression and the clinicopathological parameters and prognosis of patients with PeM.

METHODS

In a cohort of 13 MpeM patients, we evaluated histotype, nuclear grade, mitotic count, necrosis, inflammation, Ki67, BAP1, MTAP and p16 expression by immunohistochemistry, p16/CDKN2A status by FISH and TERT mRNA expression by RNAscope.

RESULTS

Our results showed several statistical correlations between TERT mRNA-score and other investigated features: (i) a poor positive correlation with BAP1 score (r = 0.06340; p ≤ 0.0001); (ii) a moderate positive correlation with p16 FISH del homo (r = 0.6340; p ≤ 0.0001); (iii) a fair negative correlation with p16 FISH del hetero (r = -0.3965; p ≤ 0.0001); a negative poor correlation with MTAP (r = -0.2443; p ≤ 0.0001); and (iv) a negative fair correlation with inflammatory infiltrate (r = -0.5407; p = 0.0233). Moreover, patients survive for a significantly longer time if they have a low mitotic index adjusted (2-4 mitotic figures per 2 mm2) (p ≤ 0.0001), are male (p = 0.0152), lose BAP1 (p = 0.0152), are p16 positive and present no deletion or heterozygous for p16 (p ≤ 0.01).

CONCLUSIONS

TERT is highly expressed in PeM, but it is not one of the crucial factors in evaluating the prognosis of patients. Nevertheless, the results validate the prognostic significance of the mitotic index, BAP1 loss and p16/CDKN2A status.

Biomarkers to predict the benefits of immune‑checkpoint blockade‑based therapy in patients with malignant peritoneal mesothelioma (Review)

Malignant peritoneal mesothelioma (MPeM) is a type of rare and highly lethal tumor. Immune checkpoint blockade (ICB)-based therapy has shown encouraging clinical activity for MPeM. However, no definitive biomarkers have been identified for predicting which patients with MPeM will benefit from ICB-based therapy. At present, there are several novel potential biomarkers proposed for predicting the response to ICB-based therapy, and biomarkers available in MPeM cells and in the tumor microenvironment have been identified with the potential to predict the efficacy of ICB-based therapy in MPeM. According to the molecular characteristics of MPeM itself, the feasibility of biomarkers in practice, and the body of available evidence, we hypothesize that the following five types of biomarkers can be used to predict the response of ICB-based therapy in patients with MPeM: Tertiary lymphoid structures, immune checkpoints and their ligands, fusion gene neoantigen burden, BRCA1-associated protein-1 haploinsufficiency and transcriptome-based biomarkers. The present review discusses the value and limitations of each type of biomarker, and potential solutions to address the limitations are proposed. The aim of the present review is to provide a background for future studies on ICB-based therapy for MPeM.

The rare occurrence of unifocal peritoneal mesothelioma: a case report, literature review, and future directions

Background

Mesothelioma is a rare, aggressive disease originating from mesothelial cells and carries a poor prognosis. Mesothelioma may arise from the pleura, pericardium, or peritoneum. Peritoneal mesothelioma (PM) usually spreads in a diffuse manner; however, a localized unifocal form of PM may occur. Literature on unifocal mesothelioma remains scarce.

Case Description

Herein, we highlight a case of localized epithelioid PM in an 81-year-old gentleman with the unique challenges faced during management. The pelvic mass was 7 cm, well-circumscribed, and hyper-vascular with fibrous attachments to the abdominal wall. The patient had a peritoneal cancer index (PCI) of 4 on initial diagnostic laparoscopy. Diagnosis was confirmed by histology. Resection of the mass with a partial omentectomy was performed. Months later, the patient developed recurrence detected on follow-up imaging in the peri-splenic region. The patient underwent cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) for 60 minutes using mitomycin C and cisplatin followed by an uneventful recovery. Our case report is followed by a review of literature on disease pathophysiology, treatment options, and recently promising immunotherapy approaches.

Conclusions

CRS and HIPEC remains the standard treatment regimen for patients with PM. Nonetheless, a more nuanced approach might be indicated in specific patients with localized unifocal PM. Disease distribution and burden may impact the decision on surgical management in selected patients.

Metachronous double primary malignant tumors with nasopharyngeal carcinoma and diffuse malignant peritoneal mesothelioma accompanied with paraneoplastic syndromes treated with nivolumab: A case report

RATIONALE

Multiple primary malignant tumors are rare and challenging to diagnose. Diffuse malignant peritoneal mesothelioma (DMPM) originate from the peritoneum, which lacks specific clinical manifestations and is difficult to diagnose, with a short survival about 10 to 13 months for inoperable ones. This is the first report of metachronous double primary malignant tumors in nasopharyngeal carcinoma and DMPM accompanied with paraneoplastic syndromes.

PATIENT CONCERNS

A 61-year-old man presented with abdominal discomfort with a history of nasopharyngeal carcinoma 5 years ago.

DIAGNOSES

The diagnosis of DMPM was finally confirmed by laparoscopic mesenteric biopsies. Paraneoplastic syndromes including increased platelets were present when diagnosis, followed by increased neutrophils after disease progression.

INTERVENTIONS

Due to intolerable for surgery, he was treated with pemetrexed combined with nivolumab, intraperitoneal infusion of nivolumab, radiotherapy, anlotinib and maintenance treatment of nivolumab.

OUTCOMES

Progression-free survival in first line is 12 months, overall survival is 23 months.

LESSONS

This indicate that comprehensive treatment including immunotherapy may be helpful for inoperable DMPM patients with nasopharyngeal carcinoma accompanied with paraneoplastic syndromes.

Genomic and transcriptomic analysis of a diffuse pleural mesothelioma patient-derived xenograft library

BACKGROUND

Diffuse pleural mesothelioma (DPM) is an aggressive malignancy that, despite recent treatment advances, has unacceptably poor outcomes. Therapeutic research in DPM is inhibited by a paucity of preclinical models that faithfully recapitulate the human disease.

METHODS

We established 22 patient-derived xenografts (PDX) from 22 patients with DPM and performed multi-omic analyses to deconvolute the mutational landscapes, global expression profiles, and molecular subtypes of these PDX models and compared features to those of the matched primary patient tumors. Targeted next-generation sequencing (NGS; MSK-IMPACT), immunohistochemistry, and histologic subtyping were performed on all available samples. RNA sequencing was performed on all available PDX samples. Clinical outcomes and treatment history were annotated for all patients. Platinum-doublet progression-free survival (PFS) was determined from the start of chemotherapy until radiographic/clinical progression and grouped into < or ≥ 6 months.

RESULTS

PDX models were established from both treatment naïve and previously treated samples and were noted to closely resemble the histology, genomic landscape, and proteomic profiles of the parent tumor. After establishing the validity of the models, transcriptomic analyses demonstrated overexpression in WNT/β-catenin, hedgehog, and TGF-β signaling and a consistent suppression of immune-related signaling in PDXs derived from patients with worse clinical outcomes.

CONCLUSIONS

These data demonstrate that DPM PDX models closely resemble the genotype and phenotype of parental tumors, and identify pathways altered in DPM for future exploration in preclinical studies.

Malignant peritoneal mesothelioma with massive ascites as the first symptom: A case report

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is an extremely rare tumor with nonspecific clinical manifestations, which is extremely difficult to diagnose. Herein, we reported a case of MPM in the abdominal cavity with massive short-term ascites as the first symptom.

CASE SUMMARY

A 65-year-old woman presented to the hospital with abdominal pain, distention, and shortness of breath that persisted for 15 d. The serum CA-125 level was 1075 U/mL. The abdominal computed tomography showed massive ascites and no obvious tumor lesions. The pathological examination of the ascitic fluid showed numerous heterotypic cells with some papillary structures. The immunohistochemistry and fluorescence in situ hybridization showed the deletion of CDX2 (-), WT-1 (-), Ki-67 (about 10% +), CEA (-), Glut-1 (+++), desmin (-), PD-L1 (-), and CDKN2A (P16). The final diagnosis was MPM. The patient refused tumor cytoreductive surgery and received two cycles of cisplatin plus pemetrexed bidirectional chemotherapy. In the second cycle, she received an additional cycle of hyperthermic intraperitoneal chemotherapy and immune checkpoint inhibitor therapy due to massive recalcitrant ascites. She died of disease progression 2 mo after diagnosis.

CONCLUSION

In case of massive unexplained ascites, the possibility of MPM should not be excluded to avoid misdiagnosis and delay in treatment.

Prognostic factors of malignant peritoneal mesothelioma: a retrospective study of 52 female patients

BACKGROUND

Prognosis in malignant peritoneal mesothelioma (MPM) remains poor, and the associated factors are unclear. Therefore, this study aimed to investigate the prognostic factors of MPM.

METHODS

A total of 52 female MPM patients treated in 2012-2017 were retrospectively analyzed. Kaplan-Meier survival curves were generated for survival analysis by the log-rank test. The Cox regression model was used for univariate and multivariate analyses.

RESULTS

Univariate analysis showed that median survival time (MST) was longer in the epithelioid type compared with the sarcomatoid type (12 months vs 5 months); cumulative survival rates at 12 months were 45.7% and 0%, respectively (P=0.005). MST was longer in patients with proliferating cell nuclear antigen (Ki67) ≤ 10% compared with those with Ki67 > 10% (15 months vs 11 months). Cumulative survival rates at 12 months were 60.0% and 28.1%, respectively (P=0.036). MSTs in patients administered peritoneal biopsy or adnexectomy + paclitaxel + platinum perfusion, peritoneal biopsy (or adnexectomy) + pemetrexed + platinum perfusion, cytoreductive surgery + paclitaxel + platinum perfusion, and cytoreductive surgery + pemetrexed + platinum perfusion were 6, 11, 12, and 24 months, respectively, with cumulative survival rates at 12 months of 0%, 35.7%, 45.5%, and 73.3%, respectively. Survival time after cytoreductive surgery combined with pemetrexed + platinum was the longest. In multivariate analysis, pathological type, T staging, and therapeutic regimen were independent prognostic factors of MPM (P < 0.05).

CONCLUSIONS

Prognosis in MPM is associated with pathological subtype, clinical staging, cytoreductive surgery, and subsequent pemetrexed use. Radical cytoreductive surgery and postoperative use of pemetrexed prolong survival.

Mesothelioma and Colorectal Cancer: Report of Four Cases with Synchronous and Metachronous Presentation

There is evidence that asbestos could play a role in the carcinogenesis of digestive cancers. The presence of asbestos fibres in histological samples from gastric, biliary, colon cancers has been reported, but the mechanism is still controversial. It has been hypothesised that asbestos reaches these sites, especially through contaminated water; however, some experimental studies have shown that the inhaled fibres are mobile, so they can migrate to many organs, directly or via blood and lymph flow. We report four unusual cases of colorectal cancers in patients with a long history of asbestos exposure who also developed synchronous or metachronous mesothelioma. We evaluated the roles of BRCA associated protein-1 (BAP1) and cyclin-dependent kinase inhibitor 2A (CDKN2A) in colon cancer and mesothelioma to support the hypothesis that BAP-1 and CDKN2A are tumour suppressor genes involved in disease progression, recurrence, or death in both digestive cancers and mesothelioma. Potentially, these markers may be used as predictors of worse prognosis, but we also stress the importance of clinical surveillance of exposed patients because asbestos could induce cancer in any organ.