Fig. 1: Effect of chronic stress on 4T1 breast cancer in vivo.

a Quantification of 4T1 primary tumor size in mice of control group and stress group over time (n = 5). b Images of the tumor xenografts from the control group and stress group are displayed 35 days after cell inoculation. c Representative lung images from the control group and stress group. d The histogram was used to compare the average numbers of metastatic nodules in the lungs from the control group and the stress group (n = 5). Data are shown as the mean ± SD; *P < 0.05.