Shi et al. reported that EphA2 KO using CRISPR/Cas9 in several syngeneic murine tumor models, including 283LM skin squamous cell carcinoma, 4T1 triple-negative breast cancer, YUMM5.2 melanoma, CT26 colon cancer, and W101 lung adenocarcinoma, led to delayed tumor growth but not in immune-deficient NSG or SCID mice. The gene discussed is EPHA2; the disease is neoplasm.