Fig. 1

Chronic stress promotes lung metastasis of breast cancer. a. Flow chart of the establishment of breast cancer mouse model with chronic restraint stress. b. Dynamic observation of tumor burdens by biofluorescence imaging in metastasis model mice. c. Fluorescence images of lung tissues in model mice with chronic stress for 3 weeks (left) and the corresponding fluorescence intensity in each group (right). d. Photo of primary tumors at 2 weeks (left) and dynamic observation of primary tumor volumes in orthotopic injection mouse model (right). e. Histological examination of lungs from orthotopic inoculation model mice at 6 weeks (left) and the percentage of metastatic area to the total lung area (right). Red arrows point to metastatic loci. f. Flow chart for the establishment of breast cancer mouse model with chronic unpredictable stress. g. Photo of primary tumors (left) and the tumor volumes (right) in orthotopic inoculation mice model with or without unpredictable stress for 2 weeks. h. Histological examination of lung tissues from breast cancer mouse model with or without unpredictable stress for 6 weeks (left) and the percentage of metastasis area to total lung area (right). Red arrows point to metastasis of breast cancer in the lung. ns: no sense, *p < 0.05, ***p < 0.001, ****p < 0.0001