Definition

A substance that blocks the activity of a protein called Bruton tyrosine kinase (BTK), which plays an important role in the development and maturation of B cells. B cells are a type of white blood cell that makes special proteins called antibodies. BTK inhibitors bind to the BTK protein, which is found on most B cells and some types of cancer cells. Blocking BTK may help keep cancer cells from growing. Some BTK inhibitors are used to treat cancer.