Clinical Oncology

The aim of this study was to evaluate the immunohistochemical expression of molecules involved in osteoclastogenesis, including the receptor activator of nuclear factor kappa B (RANK), RANK ligand (RANKL) and osteoprotegerin (OPG) in odontogenic keratocysts (OKCs), which has been named as a keratocystic odontogenic tumour by the WHO, and compare their expression with radicular cysts and ameloblastomas. RANK is a member of tumour necrosis factor receptor family and it is activated by RANK ligand. OPG binds to RANKL and inactivates it. The imbalance of these factors could cause the differential bone resorption activity in some diseases and tumours. The expression of these molecules was evaluated in ameloblastomas (n = 20), OKCs (n = 20), and radicular cysts (n = 20) by immunohistochemistry. Immunohistochemical reactivity for RANK, RANKL, and OPG was detected in neoplastic and nonneoplastic epithelium and connective tissue cells. RANK showed the greatest expression in OKCs followed by ameloblastomas, with the lowest expression seen in radicular cysts. Expression of RANKL was detected in all lesions and no significant differences were observed between groups. OPG was expressed very low in all groups. In the stroma, the number of RANK positive cells was higher in OKCs when compared with ameloblastomas and radicular cysts but radicular cyst had higher numbers of RANKL positive cells in the stroma than ameloblastomas. The molecular system of RANK/RANKL/OPG is variably expressed in OKCs, radicular cysts, and ameloblastomas and this system may be involved in the osteoclastogenic mechanisms in OKCs and ameloblastomas. Advanced studies could further clarify the role of RANK, RANKL, and OPG in mediating tumour associated bone osteolysis.

The aim of the study was to determine the apoptotic features and proliferation potential of odontogenic keratocysts compared with ameloblastomas and radicular cysts by analysing the role of bax, bcl-2, and Ki-67. The study material consisted of 20 odontogenic keratocysts, 20 radicular cysts, and 20 ameloblastomas. Immunohistochemically, bax, bcl-2 and Ki-67 were applied. The positive cells were evaluated in both neoplastic/nonneoplastic odontogenic epithelium and connective tissue cells. Ameloblastoma showed stronger bcl-2 expression than odontogenic keratocysts and radicular cysts. Bcl-2 expression in the whole thickness of epithelium and connective tissue of odontogenic keratocyst was significantly higher than radicular cyst. The expression of bax in the epithelium of radicular cyst was significantly higher than odontogenic keratocyst and ameloblastoma. The lining epithelium of odontogenic keratocyst showed stronger Ki-67 expression than ameloblastoma and radicular cyst. The proli...

Heat shock proteins (HSPs) are a class of functionally related proteins, the expression of which is increased when cells are exposed to elevated temperatures or other stresses, including infection, irradiation, heavy metals, ethanol, and oxidants. The aim of this study was to investigate the significance of HSP60, HSP70 and HSP27 as prognostic factors in different stages of oral carcinogenesis by immunohistochemical analysis. METHODS Twenty specimens of oral squamous cell carcinoma (OSCC) of the oral cavity were immunostained for HSPs to expose differences in stainability among normal epithelium (n=20) and leukoplakia (n=20) as dysplasia. RESULTS Immunohistochemistry demonstrated that OSCC cells were positive for all of HSP60, HSP70 and HSP27. Leukoplakia cases were positive for HSP70 and HSP27, but stained with variability for HSP60. Normal epithelium expressed HSP60 and to a lesser extent HSP70, while HSP27 were hardly ever expressed. The HSP70 and HSP27 stainings in OSCC were significantly higher than in normal epithelium, and demonstrated almost the same staining character as with leukoplakia. CONCLUSION Our results demonstrated that HSP immunochemistry revealed changes in especially HSP70 and HSP27 expression during tumorigenesis of squamous epithelium of the oral cavity.

P63 gene is the member of p53 gene family, found by Young in 1998 (1). It was found that the gene is located in 3q27-29 chromosome and according to presence or absence of a transcriptional activation domain, has a six isoformes, named α, β, γ subdivided into a two groups; TA p63 and ΔNp 63, characterized by different transactivation potentials and biologic properties (1-8). It was expected, that due the belongs to the familly, p63 gene behaves resembling the p53 as the tumor supressor gene. However, further investigations have shown that only one group of the TAp63 isoformes demonstrate similarity to p53 (1-8). TAp63 induces apoptosis and mediate cell cycle control by transactivation of p53 target gene, while ΔNp63 behaves dominantly negative, blocking both the activity of TAp63 and p53, inducing a cell proliferation (1-3,5,9). By this way ΔNp63 behaves as an oncogene, which has been confirmed by various studies, where different kinds of squamous cell carcinomas and oral precancerous lesions have shown an overexpression of the ΔNp63 isoformes (2,4,7-16). Except carcinogenesis, p63 isoformes play more important roles in ectodermal differentiation during embryogenesis, stem cell biology, proliferation of craniofacial structures and epithelial development (2,5,9,11,17-22).

The aim of this study is to investigate the expressions of IGF-1R, EZH2 and Laminin-5 antibodies in biopsy samples of leukoplakia and squamous cell carcinoma of the oral mucosa by immunohistochemistry method. Materials and Methods: The study consisted of three groups; oral squamous cell carcinoma leukoplakia and control groups. The control group consisted of lesions with oral fibrous hyperplasia diagnosis. Biopsies of 38 patients for oral squamous cell carcinoma, 32 patients for leukoplakia and 15 patients for control group were examined and evaluated degree of staining of antibodies. Antibodies were evaluated as negative (0-10%):0, 1 positive (11-30%):+, 2 positive (31-60%):++, 3 positive (61-100%):+++ according to staining percentages. The staining degrees of antibodies were compared with Mann Whitney U test in study and control groups. Gender distribution between groups was compared with Chi-Square test and SPSS 21 program was used for calculations. The results were statistically significancant is p ˂0.05. Results: According to the findings obtained in this study antibodies revealed significantly higher staining in the oral squamous cell carcinoma group and leukoplakia group compared to with control groups. Conclusion: In this study, it was shown that EZH2, IGF-1R and Laminin-5 may have roles in cancer development.