MICA and neoplasm: Tumor cells expressing high levels of membrane MICA molecule and other NKG2D ligands are rejected by NK cells and CD8aβT cells and stimulate antitumor activity, while reduced expression of membrane MICA molecule, as well as increased soluble MICA molecules in the serum, leads to inactivation of NKG2D-mediated antitumor response [71,72,73,74,75].