THREE-DIMENSIONAL CHANGES IN LYMPHATIC ARCHITECTURE AROUND VX2 TONGUE CANCER - DYNAMICS OF GROWTH OF CANCERS

Abstract

Many questions remain regarding themechanism of cervical lymph node metastasisvia lymphatic vessels. We report here thethree-dimensional dynamics of the lymphaticarchitecture around tumor during growth ofimplanted VX2 tongue cancer.The tongue and the deep cervical lymphnodes of rabbits were observed at 3, 7 and 10days after transplantation of VX2 cancer cells(n=5 in each group). Lymph node metastasiswas confirmed histopathologically. Morphologicalchanges of the collecting lymphaticvessels and lymphatic capillaries wereobserved, and the number and diameter ofthese lymphatic vessels were measured within500 pm around the tumor using the combinedmethod of 5'-nucleotidase (5'-Nase) stainingand three-dimensional reconstruction imaging.The VX2 cells were uniformly detectedin cervical lymph nodes ofeach rabbit of the1O-day group. The number of lymphaticcapillaries and the diameters of collectinglymphatic vessels around the tumor in the7- and 1O-day groups were greater than in the3-day group. These capillaries arose bysprouting from preexisting lymphatic vesselsand showed a tree-like branching pattern.We conclude that the dynamics of thelymphatic architecture around the tumor,especially the increase in number of capillarieson preexisting lymphatic vessels outside thetumor margin, may be associated with lymphnode metastasis.