dMMR
Pronunciation: dee-M-M-R
Also written as: dMMR — deficient Mismatch Repair
Deficient Mismatch Repair, indicating loss of function in DNA mismatch repair proteins.
Full Definition
dMMR (deficient mismatch repair) refers to the loss of function of one or more DNA mismatch repair proteins (MLH1, MSH2, MSH6, or PMS2), typically assessed through immunohistochemistry. dMMR tumors are characterized by the inability to correct DNA replication errors, leading to microsatellite instability and increased mutation rates. dMMR status is closely associated with MSI-H phenotype and serves as a predictive biomarker for immunotherapy response. Editors must understand the relationship between dMMR and MSI-H while recognizing these as distinct but related testing approaches for identifying mismatch repair deficiency.
Usage
Usage note: Use lowercase 'd' followed by uppercase MMR (dMMR, not DMMR or dmmr). Specify which proteins are deficient when known.
In Context
- "Immunohistochemistry revealed loss of MLH1 and PMS2 expression, confirming dMMR status." — pathology report
- "The dMMR endometrial carcinoma showed excellent response to pembrolizumab therapy." — clinical case report