Answer:
cleavage of MIC at the cell surface by a protease
Explanation:
The immune system refers to a complex network of cells and proteins that function to eliminate potentially tumorigenic cells on a daily basis. However, cancer cells show mechanisms in order to escape immune responses. MHC class I chain-related proteins A and B (MICA and MICB) are expressed in normal and tumorigenic cells where they act as ligands of the NKG2D receptor. The expression level of these proteins (MICA and MICB) is finely regulated by the activity of metalloproteinases (i.e., by protease-mediated cleavage), but this mechanism is altered in cancer cells. Recently, drug therapies that stimulate NKG2D mediated tumor destruction by reducing the cleavage of MICA and MICB from the surface of cancer cells have been developed.