CD226 and cancer: Considering that DNAM-1, TIGIT and TACTILE constitute an axis of paired receptors with opposite functions on NK and T cells, that are key regulators of immune surveillance after recognition of their ligands on tumor cells, (for review see [21]) and that antibodies to TIGIT are now included in clinical trials in cancer patients, a better knowledge of the expression of these receptors on T and NK lymphocytes in healthy individuals and AML patients is required for a better understanding of the mechanisms involved in cancer escape from immune effector cells.