Following STAT3 activation, MDSCs elevate the expression of pro-survival and immunosuppressive genes, such as Bcl-2 and Arg-1.38 Therefore, catecholamine suppression minimizes immunosuppression in the microenvironment by inhibiting MDSC recruitment.109 Propranolol, a pan β-AR blocker, significantly slows tumor growth in a β2-AR dependent manner. Here, STAT3 is linked to neoplasm.