The application of cancer stem cell model in malignant mesothelioma

Stemness and hybrid epithelial-mesenchymal profiles guide peritoneal dissemination of malignant mesothelioma and pseudomyxoma peritonei

Intrabdominal dissemination of malignant mesothelioma (MM) and pseudomyxoma peritonei (PMP) is poorly characterized with respect to the stemness window which malignant cells activate during their reshaping on the epithelial-mesenchymal (E/M) axis. To gain insights into stemness properties and their prognostic significance in these rarer forms of peritoneal metastases (PM), primary tumor cultures from 55 patients selected for cytoreductive surgery with hyperthermic intraperitoneal chemotherapy were analyzed for cancer stem cells (CSC) by aldehyde dehydrogenase 1 (ALDH1) and spheroid formation assays, and for expression of a set of plasticity-related genes to measure E/M transition (EMT) score. Intratumor heterogeneity was also analyzed. Samples from PM of colorectal cancer were included for comparison. Molecular data were confirmed using principal component and cluster analyses. Associations with survival were evaluated using Kaplan-Meier and Cox regression models. The activity of acetylsalicylic acid (ASA), a stemness modifier, was tested in five cultures. Significantly increased amounts of ALDH1bright-cells identified high-grade PMP, and discriminated solid masses from ascitic/mucin-embedded tumor cells in both forms of PM. Epithelial/early hybrid EMT scores and an early hybrid expression pattern correlated with pluripotency factors were significantly associated with early peritoneal progression (p = .0343 and p = .0339, respectively, log-rank test) in multivariable models. ASA impaired spheroid formation and increased cisplatin sensitivity in all five cultures. These data suggest that CSC subpopulations and hybrid E/M states may guide peritoneal spread of MM and PMP. Stemness could be exploited as targetable vulnerability to increase chemosensitivity and improve patient outcomes. Additional research is needed to confirm these preliminary data.

The Genes-Stemness-Secretome Interplay in Malignant Pleural Mesothelioma: Molecular Dynamics and Clinical Hints

MPM has a uniquely poor somatic mutational landscape, mainly driven by environmental selective pressure. This feature has dramatically limited the development of effective treatment. However, genomic events are known to be associated with MPM progression, and specific genetic signatures emerge from the exceptional crosstalk between neoplastic cells and matrix components, among which one main area of focus is hypoxia. Here we discuss the novel therapeutic strategies focused on the exploitation of MPM genetic asset and its interconnection with the surrounding hypoxic microenvironment as well as transcript products and microvesicles representing both an insight into the pathogenesis and promising actionable targets.

Global magnitude and temporal trend of mesothelioma burden along with the contribution of occupational asbestos exposure in 204 countries and territories from 1990 to 2019: Results from the Global Burden of Disease Study 2019

Understanding the burden of mesothelioma with the contribution of occupational asbestos exposure globally provides essential foundations for cancer control, policy decisions and resource allocation. Globally, 34,511 incident cases, 29,251 deaths and 668,104 disability-adjusted life years (DALYs) of mesothelioma were estimated in 2019. The age-standardized rates of incidence, mortality and DALYs all showed a slightly declining trend over the past 30 years, but the latest absolute number of mesothelioma burden almost doubled since 1990. The burden rate decreased among the population aged under 70 years, but increased among the population aged over 80 years, especially in the High socio-demographic index (SDI) region. The burden rate of mesothelioma attributable to asbestos exposure was positively associated with SDI at the national level. This study depicted a continuous increase in mesothelioma burden globally over the past 30 years. Controlling occupational asbestos exposure will reduce the mesothelioma burden, especially for higher SDI regions.