NTRK1 and gastric cancer: Here, we present an in vivo imaging model for brain tumors using human cancer cell lines, including the EGFR‐L858R/T790M‐positive H1975 lung adenocarcinoma cells, the NUGC4 hepatocyte growth factor (HGF)‐dependent gastric cancer cells, and the KM12SM colorectal cancer cells containing the TPM3‐NTRK1 gene fusion.