Dr. Saab on Immunotherapy in MSI-H GI Malignancies

Tanios Bekaii-Saab, MD, professor of medicine, Mayo Clinic, discusses immunotherapy in a patient with microsatellite instability-high (MSI-H) gastrointestinal malignancies.

Patients whose disease lacks the expression of some proteins would be classified as MSI-H, which is found in 4% of patients. This is a surrogate marker for tumors that are loaded with mutations, states Bekaii-Saab.

The presence of MSI-H phenotype is dependent on 2 elements. Firstly, it could be acquired through the genetics of the patient. Secondly, patients could acquire this sporadically, which is the majority of patients in the metastatic setting.