Ana Cláudia Garcia Rosa

Study of growth factors and receptors in carcinoma ex pleomorphic adenoma

Carcinoma ex pleomorphic adenoma (CXPA) is a rare malignant salivary gland tumor derived from a pre-existing pleomorphic adenoma. It is a good model to study the evolution of carcinogenesis, starting with in situ areas to frankly invasive carcinoma. Growth factors are associated with several biological and neoplastic processes by transmembrane receptors. In order to investigate, by immunohistochemistry, the expression of some growth factors and its receptors [EGF receptor, fibroblast growth factor, fibroblast growth factor receptor 1, fibroblast growth factor receptor 2, hepatocyte growth factor, c-Met, transforming growth factor (TGF) beta1, TGFbetaR-II and insulin-like growth factor receptor 1] in the progression of CXPA, we have used ten cases of CXPA in several degrees of invasion- intracapsular, minimally and frankly invasive carcinoma- with only epithelial component. Slides were qualitatively and semi-quantitatively evaluated according to the percentage of stained tumor cells from 0 to 3 (0 = less than 10%; 1 = 10-25%; 2 = 25-50%; 3 = more than 50% of cells). Malignant epithelial cells starting with in situ areas showed stronger expression than luminal cells of pleomorphic adenoma for all antibodies. Most of the intracapsular, minimally and frankly invasive CXPA presented score 3. However, score 2 was more evident in the frankly invasive one. In small nests of invasive carcinoma, negative cells were observed probably indicating that the proliferative process is replaced by the invasive mechanism. Altogether this data infers that these factors may contribute to cell proliferation during initial phases of the tumor.

Oral foregut cyst in a neonate.

Oral foregut cysts are congenital choristomas that arise in the oral cavity during embryonic development from remnants of foregut-derived epithelium. This is an unusual report of a neonate with a large congenital sublingual cystic lesion, extending superficially from the left ventral tongue to the anterior floor of the mouth, impeding breast-feeding. The differential diagnosis included dermoid cyst, epidermoid cyst, mucous retention cyst, and oral lymphangioma. The treatment of choice was enucleation under general anesthesia. Histology showed a cystic lesion with a ciliated pseudostratified columnar epithelium with numerous goblet cells. Immunohistochemistry was positive for cytokeratin 7 and thyroid transcription factor 1 and negative for cytokeratin 20, resulting in a final diagnosis of an oral foregut cyst. Three weeks after surgery, the tongue had healed with good mobility, and breast-feeding could be established. No recurrence was present at 6 months of follow-up.

Immunoexpression of growth factors and receptors in polymorphous low-grade adenocarcinoma.

BACKGROUND Polymorphous low-grade adenocarcinoma (PLGA) is a rare malignant tumor that usually arises in the minor salivary glands. Growth factors are cell-secreted peptides that regulate biological processes such as growth, proliferation, and differentiation. In salivary gland tumors, immunoexpression of growth factors and their receptors is associated with cell proliferation, malignant transformation, and tumor invasion. This study analyzed the expression of growth factors and receptors in PLGA, in other to better understand the mechanisms involved in the process of neoplastic cell proliferation and tumor progression. METHODS The expression of growth factors FGF-2, PDGF-A, PDGF-B and receptors FGFR-1, FGFR-2, PDGFR-α, and EGFR was analyzed in 24 PLGA samples in comparison with normal salivary glands, by immunohistochemistry. A semi-quantitative analysis determined cell positivity in all stained sections. Scores were assigned according to percentage of reactive cells: score 0 < 10%; score 1-10 to 25%; score 2-25% to 50%; score 3->50%. The level of significance was set at 5%. RESULTS Most of the growth factors and receptors, apart from FGFR-2, were significantly reactive in PLGA. Comparing to salivary acini, all of the reactive growth factors and receptors were significantly stronger in PLGA. Comparing to salivary ducts, the expression of FGF-2, PDGF-B, FGFR-1, and EGFR was significantly stronger in the nuclei and/or cytoplasm of the neoplastic cells. CONCLUSIONS The increased expression of the growth factors and receptors in the PLGA, compared to normal salivary glands, may be related to cell proliferation, somehow participating in the oncogenic process.