Objective: To observe the morphological characteristics of lymphatics and to investigate the intratumoral lymphangiogenesis in transplantation tumor model of human breast infiltrating duct carcinoma in nude mice.Methods: Small slices of human breast carcinoma tissue were transplanted into 5 nude mice to establish implanted tumor model.HE staining was used to observe the characteristics of the transplantation tumors.Vascular endothelial growth factor-3(VEGFR-3) label staining was performed to observe lymphatics

and ultrastructure of lymphatics was observed with transmission electron microscope(TEM).Results: Tumors were viable in a11 the mice

and grew up to about 0.6~0.8 centimeters in diameter after 52 days when specimen was collected.Under light microscope

lymphatics were found in all the tumors

and were located seemingly much more in periphery than in the center of the tumors.Under TEM some characteristics of neogentic lymphatics could be seen

such as thick wall

narrow lumen

changes of organell

etc.Conclusion: Neogentic lymphatics can be seen in transplantation tumor model of human breast infiltrating duct carcinoma in nude mice.