Similarly, in another case, in a patient with endometrial cancer, MMR deficiency signatures were identified in combination with high TMB, along with a PMS2 pathogenic germline variant, a somatic PMS2 start–loss mutation and a pharmacogenomic (germline) variant in the DPYD gene (associated with toxicity to fluoropyrimidines). Here, PMS2 is linked to mismatch repair cancer syndrome 1.