Extensive preclinical data have firmly established the relevance of the ADRB signaling system in cancer biology, whose effects are mediated mainly through ADRB2 activation of the protein kinase A pathway.[11–13] Several retrospective studies have examined the influence of beta-blockers on cancer survival.[16–19, 25–29] However, some studies support the protective effect of beta-blockers,[16–19] while others do not.[25–29] In most of the studies, beta-blockers were not categorized according to their beta-1 or beta-2 selectivity. The gene discussed is ADRB2; the disease is cancer.