Prognostic role of CD74, CD10 and Ki-67 immunohistochemical expression in patients with diffuse malignant peritoneal mesothelioma: a retrospective study

BACKGROUND

Diagnosis and treatment of diffuse malignant peritoneal mesothelioma (DMPM) are still challenging. The aim of the present study was to explore the correlation between CD74, CD10, Ki-67 and clinicopathological parameters, and identify independent prognostic factors of DMPM.

METHODS

Seventy patients with pathologically proven DMPM were retrospectively reviewed. The expression of CD74, CD10 and Ki-67 in peritoneal tissues was detected by immunohistochemical analysis using standard avidin biotin complex (ABC) immunostaining technique. Kaplan-Meier survival analysis and multivariate Cox regression analyses were performed to assess prognostic factors. The nomogram based on the Cox hazards regression model was established. C-index and calibration curve were performed to evaluate the accuracy of nomogram models.

RESULTS

The median age of DMPM was 62.34 years, and the male-to-female ratio was 1: 1.80. CD74 expression was identified in 52 (74.29%) of 70 specimens, CD10 in 34 (48.57%) specimens, and higher Ki-67 in 33(47.14%) specimens. CD74 was negatively associated with asbestos exposure(r = -0.278), Ki-67(r = -0.251) and TNM stage(r = -0.313). All patients were effectively followed up in the survival analysis. Univariate analysis revealed that PCI, TNM stage, treatment, Ki-67, CD74 and ECOG PS were associated with DMPM prognosis. CD74 (HR = 0.65, 95%Cl:0.46-0.91, P = 0.014), Ki-67(HR = 2.09, 95%Cl:1.18-3.73, P = 0.012),TNM stage (HR = 1.89, 95%Cl:1.16-3.09, P = 0.011), ECOG PS(HR = 2.12, 95%Cl:1.06-4.25, P = 0.034), systemic chemotherapy (HR = 0.41, 95%Cl:0.21-0.82, P = 0.011) and intraperitoneal chemotherapy (HR = 0.34, 95%Cl:0.16-0.71, P = 0.004) were independent predictors by multivariate Cox analysis. The C‑index of the nomogram for predicting overall survival (OS) was 0.81. The OS calibration curve showed good agreement between nomogram-predicted and observed survival.

CONCLUSIONS

CD74, Ki-67, TNM stage, ECOG PS and treatment were independent factors affecting prognosis of DMPM. Reasonable chemotherapy treatment might improve the prognosis of patients. The proposed nomogram was a visual tool to effectively predict the OS of DMPM patients.

Diffuse malignant peritoneal mesothelioma mimicking ovarian cancer

Diffuse malignant peritoneal mesothelioma (DMPM) and peritoneal carcinomatosis have similar computed tomography imaging features. Peritoneal carcinomatosis is a known metastatic site for many malignancies and particularly gastrointestinal tract and ovarian cancers. Also, DMPM can masquerade as an ovarian epithelial neoplasm, with very similar clinical presentation and an overlap in imaging findings. When no evident primary tumor is detected other than the peritoneal disease, primary malignant mesothelioma should be considered. Since accurate diagnosis is essential for treatment management, the gold standard in differentiating between these two entities lies in histological analysis. We report a case of DMPM that was initially misdiagnosed as an ovarian cancer, where the biopsy of a peritoneal nodule was able to correct and confirm the diagnosis of DMPM.

Peritoneal Metastases from Malignant Mesothelioma

Diffuse malignant peritoneal mesothelioma (MPM) is a rare cancer that is ultimately fatal in almost all afflicted individuals. Morbidity and mortality from MPM is due to its propensity to progress locoregionally within the abdominal cavity. Patients with MPM most commonly present with nonspecific abdominal symptoms that usually lead to diagnosis when the condition is relatively advanced. MPM is considered a chemotherapy-resistant malignancy.

miR-380-5p-mediated repression of TEP1 and TSPYL5 interferes with telomerase activity and favours the emergence of an "ALT-like" phenotype in diffuse malignant peritoneal mesothelioma cells

Background

Understanding the molecular/cellular underpinnings of diffuse malignant peritoneal mesothelioma (DMPM), a fatal malignancy with limited therapeutic options, is of utmost importance for the fruitful management of the disease. In this context, we previously found that telomerase activity (TA), which accounts for the limitless proliferative potential of cancer cells, is prognostic for disease relapse and cancer-related death in DMPM patients. Consequently, the identification of factors involved in telomerase activation/regulation may pave the way towards the development of novel therapeutic interventions for the disease. Here, the capability of miR-380-5p, a microRNA negligibly expressed in telomerase-positive DMPM clinical specimens, to interfere with telomerase-mediated telomere maintenance and, hence, with cancer cell growth was assessed on preclinical models of DMPM.

Methods

DMPM cells were transfected with a miR-380-5p synthetic precursor, and the effects of miRNA replacement were evaluated in terms of growing capability, induction of apoptosis and interference with TA. Reiterated weekly transfections were also performed in order to analyse the phenotype arising upon prolonged miR-380-5p reconstitution in DMPM cells.

Results

The ectopic expression of miR-380-5p elicited a remarkable inhibition of TA and resulted in DMPM cell growth impairment and apoptosis induction. In particular, we demonstrated for the first time that these effects were the result of a molecular circuitry converging on telomerase associated protein 1 (TEP1), where the miRNA was able to target the gene both directly in unconventional targeting modality and indirectly via p53 accumulation consequent to miRNA-mediated downregulation of testis-specific protein, Y-encoded-like 5 gene. Moreover, miR-380-5p did not cause telomere attrition and cell growth arrest in long-term DMPM transfectants, which in turn showed slightly elongated telomeres and molecular features (e.g. c-circle DNA and reduced expression levels of chromatin remodeler ATRX) resembling an alternative lengthening of telomeres (ALT) phenotype.

Conclusions

miR-380-5p interferes with TA in DMPM cells by targeting TEP1. Notably, in the long-term setting, miR-380-5p-mediated impairment of TA did not result in telomere attrition. Instead, a phenotype reminiscent of ALT emerged in DMPM cells as possible compensatory pathway that safeguards DMPM cell growth, an event that may be regarded as a potential resistance mechanism to anticancer therapies based on telomerase inhibitors.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-017-0510-3) contains supplementary material, which is available to authorized users.

Significant Clinical Benefit of Pemetrexed-based Chemotherapy for Advanced Diffuse Malignant Peritoneal Mesothelioma: A Case Presentation

Diffuse malignant peritoneal mesothelioma (DMPM) is generally an understudied disease, largely because most molecular and clinical studies of mesothelioma have been conducted in patients with the more common malignant pleural mesothelioma. We present the case of a 45-year-old male that initially presented with abdominal discomfort and ascites. Diagnostic workup revealed advanced DMPM. Bimodal treatment was stared with cytoreductive surgery and hyperthermic intraperitoneal perfusion with chemotherapy procedure, followed by pemetrexed systemic monotherapy. After the disease progression, and because of a very good previous treatment response to pemetrexed, we decided to rechallenge systemic pemetrexed, along with the introduction of cisplatin. Although the intent behind systemic treatment was at first solely palliative, overall survival after the initial diagnosis was 50 months. Treatment based on rechallenging pemetrexed with or without cisplatin in patients with advanced DMPM can result in a quite satisfactory disease control and symptom management.

Antitumor activity of miR-34a in peritoneal mesothelioma relies on c-MET and AXL inhibition: persistent activation of ERK and AKT signaling as a possible cytoprotective mechanism

Background

The value of microRNAs (miRNAs) as novel targets for cancer therapy is now widely recognized. However, no information is currently available on the expression/functional role of miRNAs in diffuse malignant peritoneal mesothelioma (DMPM), a rapidly lethal disease, poorly responsive to conventional treatments, for which the development of new therapeutic strategies is urgently needed. Here, we evaluated the expression and biological effects of miR-34a—one of the most widely deregulated miRNAs in cancer and for which a lipid-formulated mimic is already clinically available—in a large cohort of DMPM clinical samples and a unique collection of in house-developed preclinical models, with the aim to assess the potential of a miR-34a-based approach for disease treatment.

Methods

miR-34a expression was determined by qRT-PCR in 45 DMPM and 7 normal peritoneum specimens as well as in 5 DMPM cell lines. Following transfection with miR-34a mimic, the effects on DMPM cell phenotype, in terms of proliferative potential, apoptotic rate, invasion ability, and cell cycle distribution, were assessed. In addition, three subcutaneous and orthotopic DMPM xenograft models were used to examine the effect of miR-34a on tumorigenicity. The expression of miRNA targets and the activation status of relevant pathways were investigated by western blot.

Results

miR-34a was found to be down-regulated in DMPM clinical specimens and cell lines compared to normal peritoneal samples. miR-34a reconstitution in DMPM cells significantly inhibited proliferation and tumorigenicity, induced an apoptotic response, and declined invasion ability, mainly through the down-regulation of c-MET and AXL and the interference with the activation of downstream signaling. Interestingly, a persistent activation of ERK1/2 and AKT in miR-34a-reconstituted cells was found to counteract the antiproliferative and proapoptotic effects of miRNA, yet not affecting its anti-invasive activity.

Conclusions

Our preclinical data showing impressive inhibitory effects induced by miR-34a on DMPM cell proliferation, invasion, and growth in immunodeficient mice strongly suggest the potential clinical utility of a miR-34a-replacement therapy for the treatment of such a still incurable disease. On the other hand, we provide the first evidence of a potential cytoprotective/resistance mechanism that may arise towards miRNA-based therapies through the persistent activation of RTK downstream signaling.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-016-0387-6) contains supplementary material, which is available to authorized users.

p16/CDKN2A FISH in Differentiation of Diffuse Malignant Peritoneal Mesothelioma From Mesothelial Hyperplasia and Epithelial Ovarian Cancer

OBJECTIVES

It can be difficult to differentiate diffuse malignant peritoneal mesothelioma (DMPM) from reactive mesothelial hyperplasia (RMH) or peritoneal dissemination of gynecologic malignancies, such as epithelial ovarian cancer (EOC), which cause a large amount of ascites. Detection of the homozygous deletion of p16/CDKN2A (p16) by fluorescence in situ hybridization (FISH) is an effective adjunct in the diagnosis of malignant pleural mesothelioma. The aim of this study was to investigate the ability of the p16 FISH assay to differentiate DMPM from RMH and EOC.

METHODS

p16 FISH was performed in 28 DMPMs (successful in 19), 30 RMHs, and 40 EOC cases. The cutoff values of p16 FISH were more than 10% for homozygous deletion and more than 40% for heterozygous deletion.

RESULTS

According to the above criteria, nine (47.4%) of 19 successful DMPM cases were homozygous deletion positive, and three (15.8%) of 19 were heterozygous deletion positive, whereas all RMH cases were negative for the p16 deletion. In all four major histologic subtypes of EOC, neither p16 homozygous nor heterozygous deletions were detected. To differentiate DMPM from RMH or EOC, the sensitivity of the p16 homozygous deletion was 32% (9/28), and the specificity was 100%.

CONCLUSIONS

Our study suggests that p16 FISH analysis is useful in differentiating DMPM from RMH and EOC when homozygous deletion is detected.

Diffuse malignant peritoneal mesothelioma: long-term survival with complete cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC)

BACKGROUND

Prognosis of diffuse malignant peritoneal mesothelioma (DMPM) has been recently improved by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). As with other peritoneal surface malignancies, the survival benefit is maximal when a complete surgical cytoreduction is achieved, but additional factors predicting long-term outcome are still poorly understood. We sought to investigate outcome and prognostic factors in patients with DMPM treated by complete cytoreduction and HIPEC.

METHODS

From a prospective database, we selected 108 patients with DMPM undergoing complete cytoreduction (residual tumour nodules ≤2.5 mm) and closed-abdomen HIPEC with cisplatin and doxorubicin or mitomycin-C. Twenty-seven patient-, tumour- and treatment-related variables were assessed by multivariate analysis with respect to overall (OS) and progression-free (PFS) survival. A panel of immunohistochemical markers was tested.

RESULTS

Operative mortality was 1.9% and major morbidity 38.9%. Median follow-up was 48.8 months (95% confidence interval (CI) 37.1-60.6). Median OS and PFS were 63.2 months (95%CI 29.6-96.7) and 25.1 months (95%CI 5.1-45.1). The survival curve reached a plateau after 7 years, representing 19 actual survivors of 39 patients (43.6%) with potential follow-up ≥7 years. Cytokeratin 5/6, calretinin, Wilms tumour-1 (WT-1), podoplanin and epithelial growth factor receptor (EGFR) were mostly positive. At multivariate analysis, epithelial histological subtype, negative lymph-nodes, ≤10% Ki67-positive cells correlated with both increased OS and PFS. Positive podoplanin correlated to increased PFS.

CONCLUSIONS

After complete cytoreduction and HIPEC, prognosis of DMPM is primarily dependent on pathologic and biologic features. Patients with DMPM surviving ≥7 years appeared to be cured. Cure rate was 43.6%. Proliferative index and podoplanin may be used for prognostic stratification.