To determine whether TGF-β DNR expressing NK cells are able to sequester TGF-β from the tumor microenvironment and protect neighboring host immune cells, the TGF-β concentrations in NK cell supernatants obtained after 3–4 days culture in the presence versus absence of supernatant obtained from the MB cell line Daoy was measured. The gene discussed is TGFB1; the disease is neoplasm.