IL6 and neoplasm: To evaluate the role of TG2 and downstream IL-6 in tumor cell behavior in vitro, the effect of TG2 and its downstream IL-6 on in vivo tumor spreading and distant metastasis was evaluated by using highly immunocompromised NOD/scid/IL-2Rγ chain-deficient (NOG) mice, which completely lack NK activity, as well as T- and B-cell activity, as recipients [37].