Id proteins are overexpressed in human oral squamous cell carcinomas.

BACKGROUND: The helix-loop-helix (HLH) proteins Id-1, Id-2 and Id-3 have been demonstrated to inhibit the activity of transcription factors and play an important role in regulating cell growth and tissue-specific differentiation. METHODS: To elucidate the involvement of Id in human oral squamous cell carcinoma (OSCC), we examined 83 surgical specimens and eight normal gingival mucosae for the expression of Id proteins by immunohistochemistry; in addition, some specimens of the OSCC and the normal gingivae were also examined for the expression of Id-1 mRNA by in situ hybridization (ISH), while Western blots were performed on six of the tumours and on cell lysates of five OSCC cell lines. We also explored the correlation between Id expressions and cellular proliferation indicating Ki-67 or clinical parameters. RESULTS: We discovered a higher and more frequent expression of Id-1 protein (27.7%) in human OSCC compared to that of Id-2 and Id-3 proteins (6.0 and 7.2%, respectively). Western blot analysis detected Id-1 protein in four of six tumour samples and in all cell lines. ISH demonstrated strong cytoplasmic localization of Id-1 mRNA in tumour samples at significantly higher levels compared to those of normal gingival mucosae. CONCLUSION: Id-1 protein expression significantly correlates with lymph node status, indicating that increased Id expression may relate to the metastatic behaviour in human OSCC.

Prediction of delayed neck metastasis in patients with stage I/II squamous cell carcinoma of the tongue.

BACKGROUND: The incidence of delayed neck metastasis (DNM) in patients with squamous cell carcinoma (SCC) of the tongue is reported to be 20% to 50%. Although clinically negative cervical lymph nodes (N0) are associated with a good outcome, the prognosis is poor in patients with DNM. The aim of this study was to evaluate the clinicopathological and immunohistochemical parameters associated with DNM in patients with stage I/II SCC. METHODS: Fifty nine patients, with previously untreated stage I/II carcinoma, underwent examination of clinicopathological and immunohistochemical parameters and incidence of DNM. A linear discriminant analysis was used to analyze prognostic factors and to determine the probability of DNM occurring. RESULTS: DNM occurred in 14 (24%) subjects of the 59 study patients, level I to level III, within 5 years. Parameters such as gender and age, disease stage, tumor size and histological grade, tumor location, degree of tumor invasion and expression of VEGF, E-cadherin or Ki-67 showed no significant correlation with the occurrence of DNM; however, factors such as tumor morphology, tumor thickness greater than 4 mm, and Flt-4 expression were significantly associated with development of DNM. CONCLUSIONS: Such factors provide useful information with regard to DNM and the prognosis. We concluded that patients with early SCC whose tumors are > 4 mm in thickness and immunopositive for Flt-4 are particularly at risk of developing DNM.

Recombinant human bone morphogenetic protein-2 promotes osteogenesis within atelopeptide type I collagen solution by combination with rat cultured marrow cells.

We evaluated the combination effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) and cultured rat bone marrow mesenchymal stem cells (MSCs) in atelopeptide type I collagen (AC) solution on osteogenesis in a diffusion chamber (DC) to develop a bone substitute having consistent osteogenic capability for clinical applications. The cultured MSCs were obtained by 10-day primary culture of fresh bone marrow cells of Fischer rats. We prepared three groups of DCs: AC solution with rhBMP-2, AC solution with cultured MSCs, and AC solution with rhBMP-2 and cultured MSCs. The prepared combined solutions were injected into DCs, which were subcutaneously implanted into the backs of syngeneic rats. DCs were harvested after 2, 4, or 8 weeks and analyzed for bone-forming capability by determining histological and osteoblastic biochemical markers. De novo bone formation was observed both inside and outside of the membrane filter of DCs in the group of AC solution with rhBMP-2 and cultured MSCs. The alkaline phosphatase activity and osteocalcin content in the group of AC solution with rhBMP-2 and cultured MSCs were significantly higher than those in the group of AC solution with cultured MSCs at any time. These findings indicate that AC aqueous solution is a useful material not only as a carrier of rhBMP-2 but also as a cell-anchorage for differentiation and proliferation of MSCs. Therefore, this study suggests that clinical repairs of bone defects are feasible using injectable AC solution with rhBMP-2 and cultured MSCs as a bone substitute.

Epinephrine inhibits invasion of oral squamous carcinoma cells by modulating intracellular cAMP.

In oral and maxillofacial surgery, epinephrine is routinely used for cancer resection and it is important to clarify the effects of this agent on cancer. We found here that the clinically relevant concentrations of epinephrine (10, 50 and 100 microg/ml) decreased the invasion ability of oral squamous carcinoma (Sa3) cells. In the Sa3 cells treated with epinephrine (10, 50 and 100 microg/ml), migration, morphological changes and formation of actin stress fibers were inhibited and intracellular cyclic adenosine monophosphate (cAMP) increased significantly. These findings suggest that epinephrine inhibits the invasion of cancer cells by modulating intracellular cAMP and that clinicians could use epinephrine effectively for the surgical resection of the cancer.