ADRB2 and neoplasm: The immunohistochemical images of β2AR-positive cells in the tumor are shown in Figure 4A. The relative area of β2AR-positive tumor cells in the stress group was markedly higher than in the control group (p < 0.01), and the relative area of β2AR-positive tumor cells in the stress + chewing group was significantly lower than in the stress group (p < 0.01, Figure 4B).