Fig. 1. K1735 primary tumor formation requires ß3 expression. 2x10⁵ ß3-positive M2 cells or 2x10⁵ ß3-antisense-expressing M2-Tß3 cells were injected transorally into the floor of the mouth of syngeneic mice. After 4 weeks the mice were sacrificed and evaluated for tumor formation. Note that the mice injected with the M2 cells developed large primary tumors (A, left), whereas those injected with the M2-Tß3 cells were considerably smaller (A, right). (B) The average weight of tumors formed by M2 cells was 5.0 g (±1 g), whereas tumors formed by the M2-Tß3 cells averaged 1.2 g (±0.4 g). 12 mice were injected with each cell line.