DMBA誘発ハムスター歯肉癌の顎骨浸潤に関する電顕的研究

抄録

Bone invasion of the DMBA-induced gingival carcinoma in hamster was studied with electron microscope.
In the early phase of bone invasion, light microscopic observation showed the presence of muscle and/or connective tissue between the tumor and the bone on which the proliferation of osteoclasts often occurred. Electron microscopic observation revealed the development of active ruffled border of these osteoclasts. However, in the later phase, the tumor invasion near the bone surface led to the disappearance of these osteoclasts.
Direct contact of the tumor with bone was observed with the electron microscope in one case among 23 animals. Tumor cells attached to the bone with half desmosome and invaded osteocyte lacunae and bone canaliculi. But there was no development of cell organelles related to bone resorption in the cytoplasm of the tumor cells, and lamina limitans was clearly observed in the bone surface facing to the tumor. Thus, the ultrastructural evidence that the tumor cells themselves directly resorb bone matrix was not obtained, though the tumor cells attaching directly to the bone may have some functions in bone resorption.