Gene and marker tests
dMMR (mismatch repair deficient)
Also written as dMMR, MMR deficient, MMR deficiency, Loss of MLH1, Loss of MSH2, pMMR, Mismatch repair proficient
What it means
MMR deficient cells have changes in genes that correct mistakes made when DNA is copied. These cells usually have many DNA changes, which may lead to cancer. It is most common in colorectal, other digestive and womb-lining cancers.
Why it matters
Knowing if a tumour is MMR deficient may help plan treatment or predict how it responds. It can also point to an inherited condition called Lynch syndrome, which your doctor may discuss.
Ask your oncologist
"My tumour is MMR deficient. Should I be tested for an inherited condition?"
From NCI Dictionary of Cancer Terms: mismatch repair deficiency. Not medical advice: your oncologist decides.