Consistent with these data, expression of different ARs has been documented on different cancer cell types and linked to cancer progression (β1: [61, 62], β2 : [17, 61, 62], β3 : [61, 63–66], and targeting of catecholamine signaling by treatment with specific β-AR inhibitors has been proposed as a potential therapeutic approach for cancer [61, 67]. This evidence concerns the gene ADRB2 and cancer.