biostudies-literatureUnknown12(15)Wang C<h4>Background</h4>Breast cancer (BC) is the leading cause of cancer-related death among women. One of the hallmarks of cancer is sustained angiogenesis. YAP/STAT3 may promote angiogenesis and driving BC progression. This study aimed to investigate how YAP/STAT3 affects the immune microenvironment in BC and understand the underlying mechanism.<h4>Methods</h4>To establish a tumor-associated macrophages (TAMs) model, macrophages were cultured in the 4T1 cell culture medium. A BC mouse model was created by injecting 4T1 cells. The expression of YAP, STAT3, p-STAT3, VEGF, VEGFR-2, and PD-L1 was analyzed using immunofluorescence, western blotting, and quantitative real-time PCR. Flow cytometry was used to identify M1 and M2 macrophages, CD4⁺ T, CD8⁺ T, and Treg cells. LeveCancer medicine16295-16309https://www.ebi.ac.uk/biostudies/studies/S-EPMC10469732biostudies-literatureYAP/STAT3 inhibited CD8⁺ T cells activity in the breast cancer immune microenvironment by inducing M2 polarization of tumor-associated macrophages.PMC10469732He STan XWang CShen NGuo QfalseYAP/STAT3 inhibited CD8⁺ T cells activity in the breast cancer immune microenvironment by inducing M2 polarization of tumor-associated macrophages.<h4>Background</h4>Breast cancer (BC) is the leading cause of cancer-related death among women. One of the hallmarks of cancer is sustained angiogenesis. YAP/STAT3 may promote angiogenesis and driving BC progression. This study aimed to investigate how YAP/STAT3 affects the immune microenvironment in BC and understand the underlying mechanism.<h4>Methods</h4>To establish a tumor-associated macrophages (TAMs) model, macrophages were cultured in the 4T1 cell culture medium. A BC mouse model was created by injecting 4T1 cells. The expression of YAP, STAT3, p-STAT3, VEGF, VEGFR-2, and PD-L1 was analyzed using immunofluorescence, western blotting, and quantitative real-time PCR. Flow cytometry was used to identify M1 and M2 macrophages, CD4⁺ T, CD8⁺ T, and Treg cells. Leve2023-01-01T00:00:00Z2023 Aug2025-04-19T20:04:26.175Z2025-04-19T20:04:26.175ZS-EPMC104697323732918810.1002/cam4.6242