transforming-growth-factor-beta and Carcinoma--Mucoepidermoid

Mucoepidermoid carcinoma (MEC) is the most common malignant salivary tumour, classified as low, intermediate and high grade. Myofibroblasts are the main stromal component and are included as prognostic factor in some tumours. The aim of this study was to evaluate the myofibroblasts in the stroma of MEC with possible relationship to malignancy grading.. Twenty-five cases of MEC (six low grade, 11 intermediate grade, four high grade and four metastasis) were stained for vimentin, desmin and smooth muscle actin (SMA) for the identification of myofibroblasts. Transforming growth factors (TGFbeta1 and TGFbetaRII) were also assessed in our study.. Myofibroblasts were present in all cases, in amounts varying according to histological grading. TGFbeta1 was positive in squamous cells of intermediate grade tumours, and in the stroma of only four cases. TGFbetaRII was positive in most squamous and intermediate cells, regardless of malignancy grading.. Our study showed that the analysis of neoplastic stroma must be added to the studies of neoplastic cells to draw a better picture leading to tumour diagnosis and prognosis.

Topics: Actins; Carcinoma, Mucoepidermoid; Desmin; Fibroblasts; Humans; Immunohistochemistry; Neoplasm Proteins; Prognosis; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Salivary Gland Neoplasms; Stromal Cells; Transforming Growth Factor beta; Transforming Growth Factor beta1; Vimentin

Mucoepidermoid carcinoma (MEC) of salivary glands is a malignant, locally aggressive neoplasm with metastatic potential. The clinical course is usually dependent on histology; however, low-grade carcinomas can result in metastases and tumor-related death. Transforming growth factor beta1 (TGF-beta1) is a potent cytokine that affects growth inhibition of various cells and stimulates extracellular matrix production and angiogenesis. Loss of TGF-beta receptor type II (TGF-beta RII) expression has been related to resistance of TGF-beta1-mediated growth control and tumor progression. In this study, we correlate MEC tumor grade with expression of TGF-beta1 and TGF-beta RII.. Immunohistochemical staining was performed on 16 MEC specimens for activated forms of TGF-beta1 and TGF-beta RII. The percentage of cells in which staining yielded positive findings for activated TGF-beta1 and TGF-beta RII was correlated with tumor grade.. Activated TGF-beta1 was detected in 16 specimens (100%) of MEC and showed strong positive and diffuse staining. Predominately cytoplasmic staining of TGF-beta1 was seen in salivary gland ducts, stroma, and endothelial cells. There was an inverse correlation between tumor grade and loss of expression of TGF-beta RII. All low-grade MEC tumors yielded positive staining results, whereas only one case of intermediate-grade MEC had TGF-beta RII expression. No high-grade MEC showed TGF-beta RII expression.. Loss of expression of TGF-beta RII correlates with tumor grade. The localization of activated TGF-beta1 within neoplastic epithelium, tumor-associated stroma, and endothelium suggests that it might play a role in the stromal proliferation and/or angiogenesis associated with MEC.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Carcinoma, Mucoepidermoid; Endothelium; Female; Humans; Immunohistochemistry; Male; Middle Aged; Parotid Neoplasms; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Submandibular Gland Neoplasms; Tongue Neoplasms; Transforming Growth Factor beta; Transforming Growth Factor beta1