We sacrificed animals according to the ILAR guidelines. Tissues (tumors and adjacent normal tissues) were fixed in 10% neutral buffered formalin to prepare formalin-fixed paraffin-embedded tissue blocks. Immunohistochemistry and H&E staining were conducted by the National Cancer Center Animal Sciences Branch. Tumor tissues for immunohistochemistry were stained with antibodies against Ki67 or F4/80 and hematoxylin and colorized using 3,3′‐diaminobenzidine. The stained tissues were digitized at 20× magnification using an Aperio AT Turbo whole-slide scanner (Leica Biosystems, USA) equipped with a clinical-grade RGB camera (Verma et al., 2019 (link)). Regions of interest were prepared and annotated with scale bars. Images from slides not stained with a primary antibody were used as a negative control. Some tissues stained with H&E, Ki67 (a proliferation marker) or F4/80 (marker for macrophage) were quantified by using HistoQuest software (TissueGnostics) (Paek et al., 2017 (link)) and Vectra 3 (Akoya Biosciences, USA) with the help of a professional operator of NCC Omics Core Center and further analyzed statistically.