ALK1 expression in oral lichen planus: a possible relation to microvessel density.

OBJECTIVE: To assess the expression of activin receptor-like kinase 1 (ALK1) and investigate its possible relationship with microvessel density (MVD) in different forms of oral lichen planus (OLP) compared to controls' biopsies. METHODS: Biopsies from 20 reticular/papular OLP (R/PLP), 20 atrophic/erosive OLP (A/ELP) patients, and 20 healthy subjects were immunohistochemically analyzed and statistically compared and correlated for ALK1 expression and MVD as assessed by CD34 expression. RESULTS: All OLP specimens revealed the presence of positive cytoplasmic CD34 immunostaining in endothelial cells, with statistically high significant MVD in each of R/PLP (Median; M = 4.40) and A/ELP (M = 7.69) compared to controls (M = 1.16) (P < 0.001). Statistically significant MVD was found in A/ELP compared to R/PLP (P < 0.001). All control specimens revealed negative ALK1 immunostaining of the few inflammatory cells found, while 85% of A/ELP cases and 70% of R/PLP cases showed positively immunostained sections for ALK-1, with statistically significant higher ALK1 expression In A/ELP (M = 1.95) compared to R/PLP (M = 0.86) (P = 0.005). No significant correlation between CD34 and ALK1 was detected in R/PLP (r = 0.081), while a barely moderate positive correlation was found in A/ELP (r = 0.396). CONCLUSIONS: ALK1 expression and MVD are increased in OLP, particularly in A/ELP type.

Genotoxic effects of dental panoramic radiograph in children.

UNLABELLED: This study was completed to evaluate chromosomal damage (micronucleus) and cellular death in exfoliated buccal mucosa cells taken from healthy children following exposure to panoramic radiation during dental radiography. METHOD: Twenty children who underwent panoramic dental radiography for diagnostic purposes were included. Cytological preparations were stained with Feulgen stain, identified under light microscopy. Micronuclei, apoptotic nuclear alterations (condensed chromatin, karyorrhexis, pyknosis) and necrosis (karyolysis) were scored. RESULTS: showed no statistically significant differences in children's micronucleated oral mucosa cells before and after panoramic dental X-Ray exposure. On the other hand, there was a statistically significant increase in nuclear alterations closely related to genotoxicity such as condensed chromatin, karyorrhexis and pyknosis, while karyolysis of oral mucosal cells did not show significant increase after panoramic X-Ray exposure. CONCLUSION: Dental panoramic radiography may not be a factor that induces chromosomal damage, but is able to promote genotoxicity in children.

Evaluation of neoplastic nature of keratocystic odontogenic tumor versus ameloblastoma.

OBJECTIVE: Although most of odontogenic tumors are benign, some of them will show locally destructive behavior, as keratocystic odontogenic tumor (KCOT) is now known as a benign but aggressive odontogenic neoplasm. The neoplastic characteristics in KCOT have been suggested from clinical as well as pathologic aspects. Matrix metalloproteinase-2 (MMP-2) is a gelatinase form of the MMPs family, which is a group of proteolytic enzymes that degrade many types of collagen. Cysteine aspartic acid-specific protease-3 (caspase-3) is the most downstream enzyme in the apoptosis-inducing protease pathway and is probably the most clearly associated with cell death. The aim of this study is to evaluate and compare the extracellular degradation potentiality (MMP-2) and apoptosis (caspase-3) of the epithelial lining in KCOT versus radicular cysts and ameloblastoma, in order to reinforce its classification as an odontogenic tumor. MATERIAL AND METHODS: Twenty-six surgical specimens including keratocyst odontogenic tumor (KCOT; n=11), ameloblastoma (AB; n=8) and radicular cysts (RC; n=7) were examined for expression of MMP-2 and caspase-3 using the immunohistochemical method. RESULTS: For MMP-2 immunoexpression, AB showed the statistically significant highest mean area percentage, followed by KCOT, while RC showed the statistically significant lowest mean area percentage. As for caspase- 3, there was no statistically significant difference between KCOT and AB, while RC showed the statistically significantly lowest mean area percentage. CONCLUSION: Overexpression of MMP-2 protein related to growth and progression of lesions analyzed and may be one of the factors enhancing the recurrence of KCOT and invasion of AB. In addition, the epithelial lining of KCOT showed a high cell turnover reinforcing its classification as an odontogenic tumor. KEY WORDS: Keratocystic odontogenic tumor (KCOT) - Ameloblastoma (AB) - Radicular cyst (RC) - Matrix metalloproteinase-2 (MMP-2) - Caspase-3.

Differential expression of c-kit and CD43 in histological subtypes of adenoid cystic carcinoma of salivary gland.

UNLABELLED: Adenoid cystic carcinoma (ACC) of the salivary gland is characterized by a prolonged but inevitably unfavorable clinical course. Recent studies have suggested that the transmembrane tyrosine kinase receptor, c-kit proto-oncogene is involved in ACC pathogenesis. CD43 is a sialoglycoprotein that is typically expressed by hematopoietic cells and their derivative neoplasms, although positivity in epithelial tumors has only been recognized recently. OBJECTIVE: The aim of this study was to evaluate c-kit and CD43 immunoreactivity in ACCs and to compare the extent of their expression in various histologically defined subgroups of ACC, and their probable involvement in ACC pathogenesis. STUDY DESIGN: Formalin-fixed paraffin-embedded sections from 35 ACCs were immunostained for c-kit and CD43 using monoclonal antibodies. RESULTS: Cytoplasmic and membranous c-kit immunoreactivity was detected in 25/35 ACCs (71.4%) with strong immunostaining observed in solid pattern of ACC. Cytoplasmic and membranous CD43 immunoreactivity was detected in 18/35 (51.4%) of ACCs with strong immunostaining seen in the cribriform pattern. CONCLUSIONS: These results suggested that c-kit could be used as a prognostic marker for ACC and specific c-kit tyrosine kinase inhibitors such as imatinib, might be used in future therapeutic approaches against subgroups of ACC. CD43 appears to be preferentially expressed in salivary gland ACCs. Its expression decreased with cellular dedifferentiation and there was an inverse relationship between immunoexpression of c-kit and CD43 among ACC of salivary gland.

Exploration of the histogenesis of congenital granular cell epulis: an immunohistochemical study.

OBJECTIVE: Congenital granular cell epulis is a benign soft tissue lesion of the neonate that arises from the alveolar ridges of the jaws in newborns. The aim of this study is to define the histogenesis of congenital granular cell epulis by using several immunohistochemical markers. MATERIALS AND METHODS: A series of six cases of congenital granular cell epulis were immunostained with a panel of antibodies (NSE, CD68, CD99, Mesothelin, Inhibin-a, GFAP, Dystrophin, NGFR/p75 and TLR1). The percentage of positive cells was measured in the form of area percent using an image analysis software (Leica- Qwin) system. Analysis of Variance (ANOVA) was used to compare between means of positive immunostaining antibodies. RESULTS: Granular cells of all cases showed positive cytoplasmic immunostaining for NSE and CD68. The interstitial cells of five cases showed immunopositivity for CD99. Granular and interstitial cells in all cases were negative with the remaining antibodies. The immunoreactivity of the granular cells to NSE showed the statistically significantly highest mean area percent. This was followed by CD68 which showed lower values. The immunoreactivity of the interstitial cells to CD99 showed the statistically significantly lowest mean area percent. CONCLUSION: The expression of NSE and CD99 in all cases of the present study support a neuroectodermal derivation of congenital granular cell epulis.