Malignant pleural mesothelioma (MPM) is a rare cancer usually caused by asbestos exposure and associated with a very poor prognosis. After more than a decade without new therapeutic options, immune checkpoint inhibitors (ICIs) demonstrated superiority over standard chemotherapy, with improved overall survival in the first and later-line settings. However, a significant proportion of patients still do not derive benefit from ICIs, highlighting the need for new treatment strategies and predictive biomarkers of response. Combinations with chemo-immunotherapy or ICIs and anti-VEGF are currently being evaluated in clinical trials and might change the standard of care in the near future. Alternatively, some non-ICI immunotherapeutic approaches, such as mesothelin targeted CAR-T cells or denditric-cells vaccines, have shown promising results in early phases of trials and are still in development. Finally, immunotherapy with ICIs is also being evaluated in the peri-operative setting, in the minority of patients presenting with resectable disease. The goal of this review is to discuss the current role of immunotherapy in the management of malignant pleural mesothelioma, as well as promising future therapeutic directions.

Although obesity is a major risk factor for cancer, it may also improve the response to cancer therapy. Here we investigated the impact of obesity on the efficacy of immune checkpoint inhibitors (ICI). In male mice, obesity promoted tumor growth but enhanced the response to ICI. This was associated with higher expression of immune-related genes within the tumor and enhanced infiltration of tumor-specific CD8 ⁺ T cells. Further, obesity in mice was associated with higher estrogen levels and enrichment of estrogen response genes in the tumor, and anti–programmed cell death 1 (anti–PD-1) efficacy was reduced upon administration of the aromatase inhibitor letrozole, which blocks the production of estrogens. Mechanistically, adipocyte-derived estrogens increased antigen presentation by dendritic cells and tumor-specific CD8 ⁺ T cell cytotoxicity. Last, overweight and obese men with melanoma responded better to ICI, with high estrogen levels being associated with improved response and survival. Our results suggest that estrogens may serve as a predictive factor of response to ICI in men with melanoma.