Inhibition of DMBA-induced Oral Squamous Cells Carcinoma Growth by Brazilian Red Propolis in Rodent Model.

We investigated the effect of oral administration of hydroalcoholic extract of Brazilian red propolis (HERP) on DMBA-induced oral squamous cell carcinomas (OSCC) in rodents. The chemical components of the HERP were assessed by high-performance liquid chromatography (HPLC). Carcinogenesis was topically induced in the lower lip of 25 rats using 9,10-dimethyl-1,2-benzanthracene (DMBA); the tumour was treated with saline (TUM1) and Tween 80 (TUM2) as well as HERP at 10, 50 and 100 mg/kg (HERP10, HERP50 and HERP100, respectively) for 20 weeks. Topical application of saline and oral administration of 100 mg/kg HERP was used in five rats as a control group (CTR). After 26 weeks, the histological malignancy grading and immunohistochemical expression of Ki-67 and p16(INK4A) were assessed in the tumours/tissue samples. The compounds identified were propyl gallate, daidzein, catechin, epicatechin, formononetin and biochanin A. Formononetin, daidzein and biochanin A showed concentration of 23.29, 0.38 and 0.67 mg/g of HERP, respectively. HERP at doses of 50 and 100 mg/kg inhibited 40% of OSCC growth and promoted a 3-week delay in development of clinically detectable tumours. Epithelial dysplasia was observed in all samples with no clinical tumour, except in CTR. No significant difference in the immunoexpression of Ki-67 and p16(INK4A) was observed between HERP-treated and saline/Tween 80-treated groups (p > 0.05). Our results suggest that HERP exerts chemopreventive activity on the progression of DMBA-induced epithelial dysplasia to OSCC in an experimental model of labial carcinogenesis; however, this effect is not associated with Ki-67 and p16(INK4A) immunoexpression.

Plasmacytoid myoepithelioma of minor salivary glands: report of case with emphasis in the immunohistochemical findings.

Myoepithelioma is a rare benign tumor of the salivary glands and is usually seen in the parotid gland and the minor salivary glands. It was once considered to be a type of pleomorphic adenoma (PA), but myoepitheliomas are today believed to be relatively aggressive tumors. Myoepitheliomas are most common in young adults between the ages of 30 and 50 and there are very few cases reported in individuals less than 18 years of age. We report a case of myoepithelioma located in the hard palate in a 15-year-old Brazilian male. The tumor was composed of plasmacytoid myoepithelial cells. An analysis of the immunohistochemical profile of the tumor cells showed positivity for vimentin, S-100 protein, and glial fibrillary acidic protein (GFAP), but not for smooth muscle actin (α-SMA) and cytokeratin 14 (CK14). We report this case because of the rarity of this tumor, especially in adolescents. We also discuss the histological parameters of the differential diagnosis of this tumor as well as its immunohistochemical profile.