The components of this system include: (1) down-regulation of MHC-I molecules in the tumour cells, by which the tumour cells make themselves difficult for the immune system to identify and attack [31]; (2) secretion of TGF-β and other immune inhibition molecules which counterattack the strikes from the lymphocytes [31]; and (3) establishment of physical barriers which blocks the approach of immune cells to the tumour cells. The gene discussed is TGFB1; the disease is neoplasm.