: clinical aspects, and therapeutic Malignant peritoneal mesothelioma

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, pairedbox 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. Keywords Peritoneal, mesothelioma, cytoreductive surgery, heated intraperitoneal chemotherapy, genomic profiling Ann Gastroenterol 2018; 31(6): 1-11 Introduction Mesothelioma arises primarily from the mesothelial cells of the serosal membrane lining the pleural, peritoneal and pericardial cavities, and the tunica vaginalis. Among the various types of mesothelioma, diffuse malignant peritoneal mesothelioma (MPM) accounts for nearly one-fourth of cases, with an estimated annual incidence of 2500 cases worldwide [1]. MPM is a heterogeneous, aggressive tumor mainly caused by exposure to asbestos or other carcinogens such as talcum; 33% of diagnosed patients have a history of asbestos exposure, a clearly lower rate than that in patients with malignant pleural mesothelioma [2]. Chronic peritonitis is a less clear risk factor [3]. Patients with MPM are more commonly female, of younger age, and have a better prognosis than those with pleural mesothelioma [4]. The disease typically presents with non-specific features, including abdominal pain,