Reduced tumor burden in src^–/– mice but not fyn^–/– mice following experimental lung metastasis of invasive melanoma. Syngeneic B16F10 melanoma cells were injected intravenously in the tail vein of src^–/– and control src^+/– mice, and lung tumor burden determined after 15 days, as described in “Materials and methods.” (A) Wet lung weights of B16 tumors from src^–/– and src^+/– are shown (*P < .05) (n = 5). (B) Representative stereomicrographs of lung tumor burden are shown from src^–/– or control src^+/+ hosts. Administration of B16F10 tumor cells into fyn^–/– and control wild-type (WT) mice was performed by intravenous injection of tumor cells as described previously. (C) Wet lung weights of WT (fyn^+/+) and fyn^–/– mice are shown (P > .2) (n = 5). For panels A and C, error bars indicate standard error. (D) Representative stereomicrographs of lung tumor burden are shown from WT (fyn^+/+) or fyn^–/– hosts.