Mismatch repair and clinical response to immune checkpoint inhibitors in endometrial cancer

Lay Summary

• Endometrial cancer is common, and a subset recurs and requires additional treatment.

• Some of these are recognized as being susceptible to immune therapies and are said to have mismatch repair deficiency (dMMR).

• However, this clinical trial highlights which cases are more likely to respond well: those containing mutations in genes known as Lynch genes and also some with mutations in POLE/POLD1 (“ultra‐hypermutation” genes).

• In contrast, the majority of dMMR endometrial cancers have silencing or DNA methylation of one of these genes, MLH1, and do not seem to be as responsive to single‐agent immune therapy.

• The availability of combination therapies may be important to consider for these women.