Establishment of a murine model of bone invasion by oral squamous cell carcinoma.

This study examines the establishment an animal model of bone invasion by oral squamous cell carcinoma to clarify the mechanisms of osteoclast-mediated bone invasion. C(3)H/HeN mice were inoculated with SCCVII cells into the masseter region. At the end of week 3, all surviving mice were sacrificed and analyzed by three-dimensional imaging using micro-computed tomography, histopathological observation using Hematoxylin-Eosin staining and Tartrate-Resistant Acid Phosphatase staining, and confirmation of mRNA expression of the osteoclast-related cytokines IL-6, TNF-alpha, and PTHrP. SCCVII cells rapidly multiplied in the masseter muscle of the mice. Bone invasion was evident only in the SCCVII transplanted group on micro-computed tomography. The histopathologic findings obtained with H-E and TRAP staining indicated that the tumor cells in the mandible of all animals of the SCCVII transplanted group exhibited funicular invasion and presented a serrated pattern of bone resorption. The mRNA expression of IL-6, PTHrP, and TNF-alpha increased as the control decreased. SCCVII cells were highly invasive into mandibular bone in C(3)H/HeN mice. This model was similar to the invasion of human oral cancer into maxillary and mandibular bone. Our mandibular invasion model may provide a powerful new modality for the diagnosis and treatment of oral cancer with bone invasion.