Figure 4: Mean density of LYVE-1 on orthotopic colon tumors expressing different levels of EGFR. The SW620CE2 is human colon cancer cell line. SW620 cells were injected into the cecal wall of nude mice. Three months after the injection, cecal tumors were harvested. Cells were established in culture. Primary cultures were passaged in vitro two or three times, and then, cells were injected into the cecum of another set of nude mice. The selection cycle was repeated two times to yield cell lines designated SW620CE2. SW620CE2 did not produce detectable levels of EGFR. SW620CE2/EGFR was established from SW620CE2 which was transfected sense EGFR plasmids. Cells () in 50 μL of Hanks’ buffered saline solution were injected into the cecal wall of nude mice. The number of lymphatic vessels in SW620CE2/EGFR tumors was fourfold higher than that observed in SW620CE2 tumors .