Mismatch repair deficiency refers to a characteristic of some cancer cells that create a large number of changes in the DNA, leading to new products that can be attacked by the immune system during immunotherapy. Image: Andrew H. Lee
Why immunotherapy does not cure half of cancer patients - cancer short science news

Scientists have discovered why cancers in about half of the cancer patients do not respond to immunotherapy. Analysis of tumors in mice and humans revealed that those cancers that do respond have a higher degree of microsatellite instability (MSI) than those with a lower MSI.

This means that the DNA of cancers with high MSI is changed considerably. This may give rise to new proteins in cancer cells that the immune system can attack.

Thus, the level of MSI can now be used as a biomarker, like a crystal ball, to predict which patient will benefit from immunotherapy and which patient will not.

Read the full story: Johns Hopkins
Scientific publication: Science