NCAM1 and glioblastoma: In contrast, the frequency of activated CD56+/CD69+ NK cells is significantly increased in patients with astrocytoma (** p < 0.01) and GBM (** p < 0.01) compared to the healthy controls (median frequencies of 3.1% (astrocytoma) and 2.5% (GBM) versus 0.9% (healthy donors)).