metallothionein and Ameloblastoma

This study was focused on the immunohistochemical profile of the adenomatoid odontogenic tumor. A Pub/Medline search revealed a number of immunohistochemical studies including cytokeratin profiles, extracellular matrix proteins, Integrins, ameloblast-associated proteins resorption regulators (RANK, RANKL), p53, PCNA, MDM2 protein, cyclin D1, Ki-67, Bcl-2 metallothionein, metalloproteinases, D56 hepatocyte growth factor, c-met, DNA methyltransferase, podoplanin, TGF-βI, Smad-2/3, Smad-I-5/-8, Smad 4, beta- catenin, calretinin, and clonality. Careful interpretation of the findings indicates that the adenomatoid odontogenic tumor may be more of a hamartomatous than neoplastic nature.

Topics: Ameloblastoma; DNA Modification Methylases; Extracellular Matrix Proteins; Humans; Immunohistochemistry; Intercellular Signaling Peptides and Proteins; Jaw Neoplasms; Keratins; Membrane Proteins; Metalloproteases; Metallothionein; Neoplasm Proteins; Nuclear Proteins

Odontogenic tumors exhibited variable biologica behaviors. Metallothionein (MT) is correlated with the cellular homeostasis of essential metals, cellular differentiation, and proliferation. The core goals of this study are (i) to report and to compare MT expression among benign epithelial odontogenic tumors; (ii) to correlate MT with cellular proliferation index; and (iii) to evaluate the influence of the inflammatory infiltrate on MT expression.. Ten cases of solid ameloblastomas (SABs), 4 squamous odontogenic tumors (SOTs), 5 adenomatoid odontogenic tumors (AOTs), and 3 calcifying epithelial odontogenic tumors (CEOTs) were subjected to immunohistochemical to anti-MT, anti-Ki-67, and anti-PCNA. Statistical analysis was performed using BioEstat(®) 4.0.. Metallothionein staining was found to be the highest in the SABs (93.1%), followed by SOTs (52.9%), AOTs (38.4%), and CEOTs (0%). MT staining exhibited statistically significant differences between the SABs and the SOTs (P = 0.0047) and the AOTs (P = 0.0022). A weak-to-strong positive correlation between IMT and IK or IP was observed in SABs and SOTs, whereas a strong negative correlation was observed in AOTs. No differences in IMT, IK, and IP were observed between inflammation groups A and B.. The increased MT expression observed in the SABs might be correlated with clinical behavior (local invasiveness and high rate of recurrence). In the SABs and SOTs, MT plays a role in the stimulation of cellular proliferation. In contrast, MT can inhibit cellular proliferation in the AOT. The IMT, IK, and IP are not affected by inflammation.

Topics: Ameloblastoma; Cell Proliferation; Connective Tissue; Epithelial Cells; Humans; Immunohistochemistry; Ki-67 Antigen; Lymphocytes; Metallothionein; Neoplasm Invasiveness; Neoplasm Recurrence, Local; Odontogenic Tumor, Squamous; Odontogenic Tumors; Plasma Cells; Proliferating Cell Nuclear Antigen; Skin Neoplasms

Ameloblastoma is a benign odontogenic tumor, exhibiting local invasiveness and high rate of recurrence. Metallothionein is a protein associated with tumorigenesis, serving as prognostic factor in different neoplasms. We are interested in mechanisms underlying ameloblastoma local invasiveness. Thus, we decided to analyze expression of metallothionein in this tumor.. An immunohistochemical evaluation of metallothionein in ameloblastoma was carried out. As control, we assessed expression of the same molecule in calcifying cystic odontogenic tumor (CCOT), a non-invasive odontogenic neoplasm with ameloblastomatous epithelium.. We studied 12 cases of solid/multicystic ameloblastomas. Metallothionein was observed in all samples. This molecule was observed in columnar cells in the periphery and in central polyhedral cells. CCOT (four cases) also showed the presence of metallothionein. Morphometry of stained areas showed that expression of metallothionein in ameloblastoma was significantly higher compared to CCOT (P < 0.0001).. This protein may have an impact on ameloblastoma behavior. Metallothionein would act as a zinc reservoir for important proteases related to ameloblastoma biology, such as MMPs. This protein could also display pro-mitotic and anti-apoptotic features in the tumor.

Topics: Ameloblastoma; Case-Control Studies; Gene Expression Regulation, Neoplastic; Humans; Metallothionein; Neoplasm Invasiveness; Odontogenic Tumors; Skin Neoplasms