[MSI Metastatic solid tumors treatment and immunotherapies].

Checkpoints inhibitors are known to induce striking tumor responses in advanced MSI colorectal cancers, which used to be related to a poor clinical outcome. The incidence of the MSI phenotype is highly heterogeneous across non-colorectal cancers. The highest incidence rates are found in endometrioid forms of uterine cancers and in gastric tumors (20 to 40 % and 10 to 33 %, respectively). The association between a "MSI" tumor phenotype and other clinical or biological tumor characteristics is still under debate. Its prognostic value has not been determined yet. The deficiency of the DNA mismatch repair (dMMR) system of such tumor cells increases their mutational load and induces the production of so-called neo-antigens. Therefore, checkpoint inhibitors are a target therapeutic class for this molecular group of tumors. For example, response rates reach more than 50 % in pre-treated advanced endometrial cancers and in metastatic gastric tumors in association with a first line of chemotherapy. Those promising results imply the development of reliable biomarkers predictive of tumor response to immunotherapy. The present article summarizes the clinical outcomes related to the administration of checkpoint inhibitors in non-colorectal cancers. The ongoing clinical trials of such therapeutic class in this patient population are displayed.