<qa>  What is one of the predominant mechanisms of action?There are many mechanisms involved in the antitumor effect of the antibodies including the induction of apoptosis, blocking angiogenesis, blockade of intracellular signaling pathways, and activation of complement leading to lysis of tumor cells. However it appears that the antibody-dependent cellular cytotoxicity ADCC is one of the predominant mechanisms of action. It is important to note that in order to obtain a powerful ADCC effect it is necessary the action of the antibody but also the activity of the effector cell, and thus the competence of the immune system of the guest. There are different cellular subpopulations that mediate the ADCC effect. CTL and NK are two of these subpopulations that can be reduced in patients with cancer. 