Tongue tumor and cervical lymph node metastasis of SCCOT orthotopic xenografts. (A) Primary tongue tumor after orthotopic sublingual implantation of OSC-19 cells isolated from a patient with a well-differentiated squamous cell carcinoma. The tongues of nude mice were inoculated with OSC-19 cells, and mice were sacrificed after 35 days. Necropsy was then performed and an obvious tumor was seen in the tongue. (B) Regional metastasis from orthotopic sublingual implantation of luciferase-transduced OSC-19 LN2-Luc cells. OSC-19 LN2-Luc cells were injected into the tips of the mice's tongues. Thirteen days after cell inoculation, the primary tumor was removed surgically. On day 82, increased intensity of photon emission from the cervical lymph node metastasis was observed. (C) and (D) Hematoxyilin and eosin slides of the OSC-19 tongue tumor and cervical lymph node of OSC-19 revealed squamous cell carcinoma in locations (*).