To test this hypothesis, 231LUC+ triple negative breast cancer tumors that were orthotopically implanted in SS.BN3IL2Rγ- and SSIL2Rγ- rats were collected at 10 days post-implantation and analyzed for DLL4-positive blood vessel density by immunofluorescent staining and for the distribution of TNPs by dark field imaging. Here, DLL4 is linked to triple-negative breast carcinoma.