A study of osteoclast-related cytokines in mandibular invasion by squamous cell carcinoma

The purpose of this study was to analyze the mechanism of bone invasion in carcinoma of the mandibular gingiva. We investigated 38 specimens of lower gingival carcinoma and histopathologically classified them into an invasion group (23 cases) and a non-invasion group (15 cases) on the basis of light microscopy evidence. These specimens were examined using immunohistochemical techniques involving antibodies of parathyroid hormone-related protein (PTHrP), tumor necrosis factor (TNF)-α, interleukin (IL)-1α, -1β, -6, -11, -18 and transforming growth factor (TGF)-β. The invasion group showed a high level of expression of PTHrP, TNF-α, IL-6 and IL-11 positive cells (P < 0.01 versus non-invasion group). The difference in the levels of expression of IL-1α, -1β, -18 and TGF-β positive cells was not significant between these two groups. Our results suggest that various cancer-derived cytokines, such as PTHrP, TNF-α, IL-6 and IL-11, play an important role in the mechanism of bone invasion associated with lower gingival squamous cell carcinoma.