TGFB1 and neoplasm: Although patient PB-NK and PE-NK cells are not fully anergic as they respond to stimulation by IL-2 in the culture medium, however, addition of TGFβ or iPE or tmPE fluids resulted in a strong inhibition of this crucial effector function of NK cells, even in healthy donor NK cells, suggesting a predominant role for the PE tumor microenvironment in the establishment of an alternative NK cell activation status.