A poor prognosis of oral squamous cell carcinoma (SCC) is partly due to the invasiveness and metastasis of the tumor. One of key elements in tumor invasion and metastasis in the degradation of extracellular matrix is tissue inhibitors of metalloproteinases (TIMPs). This study was performed to determine the expression of TIMP-1 and TIMP-2 of oral SCCs with regard to the histologic invasiveness and differentiation in 5 normal oral mucosa and 36 oral SCCs. The histologic invasiveness of oral SCCs were classified into 4 grades. The differentiation of oral SCCs was divided into 3 grades. The StreptAvidin-Biotin immunohistochemical process, using TIMP-1 and TIMP-2 monoclonal antibodies, was performed to determine the expression of TIMP-1 and TIMP-2. The expression of TIMP-1 was positive in 5 of 17 oral SCCs with weak invasiveness and was positive in 8 of 19 oral SCCs with strong invasiveness. The TIMP-1 expression did not increase significantly with respect to the invasiveness of oral SCCs (P>0.05). The expression of TIMP-2 was strongly positive in 5 out of 17 SCCs with weak invasiveness and was strongly positive in 15 of 19 SCCs with strong invasiveness. The TIMP-2 expression increased significantly with respect to the invasiveness of oral SCCs; the stronger the expression, the stronger the invasiveness (P<0.05). The expression of TIMP-1 and TIMP-2 did not increase significantly with respect to the histologic differentiation. We concluded that with respect to the invasiveness, the TIMP-2 expression increases significantly in oral SCCs but the TIMP-1 expression does not; and that with respect to the histologic differentiation, their expressions do not increase significantly. These results suggested that TIMP-2 can be used as a tool to evaluate the invasiveness of oral SCCs.

The origin of squamous cell components in salivary gland tumor has been not yet clarified in detail. The squamous cell differentiation from adenocarcinoma has been reported in various carcinoma by HPV transfection in vitro. The adenocarcinoma cells adjacent to the squamous cell carcinoma components were positive for HPV. This is thought to indicate that after adenocarcinoma cells are transfected with HPV, they undergo morphological changes, and that squamous cell differentiation follows. The purpose of this study were to examine the effects of HPV-16 E6/E7 gene transfection into SGT cell line from human salivary gland adenocarcinoma, and to study the relation between the E6/E7 gene and squamous differentiation. Plasmid pBR322 containing HPV-16 was transfected into cultured SGT cell line using lipofectin method. Hygromycin was used as a selection marker. The presence of HPV E6/E7, transglutaminase 1, and involucrin mRNAs and protein in E6/E7 gene transfected cells was investigated by RT-PCR and immunoslot blot method. The apoptosis index was analysed by flow cytometry. The growth rate of E6/E7 gene transfected cells was reduced. E6/E7 transfected SGT cells increased apoptosis index. Involucrin and TGase I mRNAs by the squamous cell differentiation was most conspicuous in the E6/E7 gene transfected cell compared with non transfected cells. Squamous cell differentiation demonstrated in the transfectedSGT cell line, which expressed E6/E7 fusion gene mRNA.E6/E7 gene transfected cells showed squamous cell differentiation, expressing involucrin and TGase 1 protein by immunoslot blotting. The transfected SGT cell which expressed E6/E7 gene mRNA showed the squamous cell differentiation particularly clearly, and apoptosis was also demonstrated. It suggested that E6/E7 gene transfection into human salivary gland adenocarcinoma cells might induce clear squamous cell differentiation and contribute to study the pathogenesis of human salivary gland adenocarcinoma.

A case of a distinctive variety of basalαd squamous cell carcinoma (B8CC) of the floor of mouth is described Histologic evaluation of the tumor showed lobules and aggregates of medium-sized basaloid cells with distinctive periph eral palisading and focal areas of comedo- necrosis. This appearance together with microcystic spaces simulated that of an adenoid cystic carcinoma. Accompanying epithelial dysplasia of the overlying mucosa was found. Immunohistochemistry of the tumor revealed diffuse strong expression for cytokeratin AE1/3, focally positive for Epithelial Membrane Antigen in the inner cells of tubular structures However, CEA, 8-100, smooth muscle actin, and vimentin were negative. The histologic differential diagnosis considered were adenoid cystic carcinoma and adenosquamous cell carcinoma Immunohistochemistry and awareness of this unusual pattern of B8CC will facilitate the correct diagnosis being reached.