The antitumoral activity of osimertinib is macrophage-dependent in the mouse CRC model. (A) Volume of subcutaneous MC38 tumors form Rag1−/− mice in two indicated groups. n = 6. (B) Tumor weight at necropsy in two indicated groups treated as A. n = 6. (C) Representative images of CD31 (green) and α-SMA (red) immunostaining, and DAPI nuclear staining (blue) of tumors in vehicle group and osimertinib group. (D) Relative CD31+ area in tumors of two indicated groups. Each dot indicates one tumor per mouse and represents the average of 5 images. (E) Relative proportion of α-SMA+ pericyte-covered blood vessels in tumors of two indicated groups. Each dot indicates one tumor and represents the average of 5 images. (F) Left, representative images of Ki67 immunostaining (green) and nuclear staining (blue) of tumors in two indicated groups. Right, relative nuclear Ki67 in vehicle group and osimertinib group. Each dot indicates one tumor and represents the average of 5 images. (G) Left, representative images of cleaved caspase-3 (orange) and DAPI nuclear staining (blue) of tumors in two indicated groups. Right, relative cell death in vehicle group and osimertinib group. Each dot indicates one tumor per mouse and represents the average of 5 images. (H, J) Top, schematic of the workflow for treatment as indicated. Bottom, growth curves of individual tumors from indicated groups. (I, K) Kaplan–Meier survival curves of mice treated as indicated. (D–K) n = 5. Statistical analysis by unpaired Student's t-test or log-rank test. Data are presented as mean ± SEM. Scale bar = 100 μm.