For instance, a study demonstrated increased PD-1 (programmed cell death 1), TIGIT (T cell immunoreceptor with Ig and ITIM domain) and TIM-3 (T-cell immunoglobulin and mucin domain-3) expressions on NK cells from AML patients at initial diagnosis compared to NK cells from healthy donors [103]. The gene discussed is TIGIT; the disease is acute myeloid leukemia.