TGFB1 and neoplasm: Indeed, it was shown that LMP1-transfected BALB/c 3T3 cells exhibited non-transformed phenotypes in vitro but those that lost sensitivity to TGF-β-mediated growth inhibition formed tumours in severe combined immunodeficiency (SCID) mice [78], implying that loss of TGF-β responsiveness is a critical event for the tumorigenicity of EBV-infected cells.