Quantitative analysis of argyrophilic nucleolar organizer regions and epidermal growth factor receptor in ameloblastomas

Department of Oral Pathology, School of Dentistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Journal of Oral Pathology and Medicine (Impact Factor: 1.93). 03/2007; 36(2):99-104. DOI: 10.1111/j.1600-0714.2007.00472.x
Source: PubMed


The aim of this study was to evaluate the proliferation activity by means of the quantification of the argyrophilic nucleolar organizer regions (AgNORs) and the patterns of expression of the epidermal growth factor receptor (EGFR) in ameloblastomas.
The methods of evaluation included the H/E stain for the morphologic analysis, the silver impregnation technique for quantification of the AgNORs and the immunohistochemical stain with anti-EGFR antibody in 11 cases of ameloblastoma.
The results did not show a significant statistical difference as per quantification of the AgNORs. The expression of the EGFR on the epithelial islands of ameloblastoma was not uniform, and the location of the expression was also variable. The predominant expression was that of cytoplasm and the islands with an expression of membrane only were rare and generally smaller in size.
The tumor presents an irregular growth. Smaller islands are associated with a higher proliferation activity and therefore could be responsible for tumor infiltration.

4 Reads
    • "The mechanism of such local aggressiveness is still not known. For a better understanding of the aggressive behavior of ameloblastomas, investigations were carried out using biochemical and immunohistochemical methods to study the expression of metalloproteinases, growth factor receptors and their proliferative activity.[2] Among the various methods used for evaluation of proliferative activity, argyrophilic nucleolar organizer region (AgNOR) uses silver to stain the proteins associated with the active nucleolar organizer regions (NORs). "
    [Show abstract] [Hide abstract]
    ABSTRACT: To compare the area and number of AgNORs (silver stained nucleolar organizer regions) by morphometry between follicular and plexiform variants of ameloblastoma in order to analyze their cell proliferation rates. This retrospective study was carried out on 30 cases each of follicular and plexiform ameloblastoma. The sections were obtained and stained with silver staining technique to identify the nucleolar organizer regions. AgNORs were quantified using two parameters; manual tag for the number of AgNORs and area measurement using the image analyzer software, Image-Pro-Express. Morphometric area measurements of AgNOR were significantly higher for Plexiform ameloblastoma (0.831μm(2)) than follicular ameloblastoma (0.528μm(2)). Enumeration of the number of AgNORs showed a significantly higher number of AgNOR for follicular ameloblastoma (1.71) than plexiform ameloblastoma (1.43). Among the groups studied, follicular ameloblastoma was more aggressive than plexiform ameloblastoma, as it showed smaller AgNOR area and higher AgNOR number. The combination of counting the number and measuring the area of AgNOR dots showed a significant overall difference between AgNOR profiles of follicular and plexiform variants of ameloblastoma.
    Journal of Oral and Maxillofacial Pathology 09/2012; 16(3):354-8. DOI:10.4103/0973-029X.102483
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim was to evaluate the expression of matrix metalloproteinases (MMPs) 7 and 26 in ameloblastomas and adenomatoid odontogenic tumors (AOTs). Twenty intraosseous solid ameloblastomas and 10 intraosseous AOTs were evaluated regarding immunohistochemical expression of MMP-7 and -26 in the epithelium and stroma. There was no statistically significant difference in MMP-7 and -26 expression between the epithelium of ameloblastomas (P = .50) and AOTs (P = .90). Stromal staining for MMP-7 was evident in all cases. For MMP-26, stromal staining was observed in 65% of ameloblastomas and 50% of AOTs, and this difference was not statistically significant (P = .69). The marked expression of these matrilysins suggests their role in the process of tissue remodeling and growth in the studied tumors, but it does not relate to the their distinct patterns of aggressiveness.
    Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 07/2009; 108(3):417-24. DOI:10.1016/j.tripleo.2009.03.035 · 1.46 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Giant cell lesions of the jaws are considerably similar according to histopathologic characteristics yet show different clinical behaviors. These lesions include central giant cell granuloma (CGCG), aneurysmal bone cyst, Cherubism, and Brown tumor associated with hyperparathyroidism. The present study aimed to investigate AgNORs count in these lesions as a proliferative marker and to determine whether it can be used to discriminate between them or not. Forty-one cases of giant cell lesions of jaws were retrived from Oral Pathology Department (1987-2007). They included 21 cases of CGCG, eight cases of aneurysmal bone cyst (ABC), six cases of Cherubism, six cases of Brown tumor. The mean AgNORs count was calculated for all cases. To compare mean AgNORs in groups of lesions, ANOVA test was performed. Mean AgNOR counts were: (0/85 +/- 0/29) in CGCG, (0/76 +/- 0/32) in ABC (0/87 +/- 0/10) in Cherubism and (0/82 +/- 0/16) in Brown tumor. A significant difference was not observed in AgNOR counts among these groups of lesions. Jaws giant cell containing lesions have no acceptable differences in mean AgNORs.
    Journal of Oral Pathology and Medicine 02/2010; 39(5):431-4. DOI:10.1111/j.1600-0714.2009.00872.x · 1.93 Impact Factor
Show more