Peroxiredoxin I, platelet-derived growth factor A, and platelet-derived growth factor receptor alpha are overexpressed in carcinoma ex pleomorphic adenoma: association with malignant transformation

Two sides of the same coin: Insights into the myoepithelial cells in carcinoma ex pleomorphic adenoma development

The myoepithelial cell seems to play an important role as a tumor suppressor in the development of carcinoma ex pleomorphic adenoma. Nevertheless, interesting aspects concerning the other side of the coin, i.e., the contribution of the myoepithelial cell to cell proliferation, were brought to light. Here we highlighted the studies in which myoepithelial cells were presented as tumor suppressors and promoters in the context of PA malignant transformation. In conclusion, even if in a paracrine way, divergent signals can alter the suppressor role of the myoepithelial cell and induce it to compose a microenvironment propitious to the tumor progression of the malignant cells. This would cause myoepithelial cells to succumb and malignant epithelial cells to initiate progression beyond the basal membrane.

Concomitant expression of ezrin and HER2 predicts distant metastasis and poor prognosis of patients with salivary gland carcinomas

Salivary gland carcinomas (SGCs) exhibit heterogeneous biological behaviors, including the formation of distant metastases, which is a critical event associated with poor prognosis. Ezrin, which is a member of the ezrin-radixin-moesin family of plasma membrane-cytoskeleton linker proteins, may provide a marker for metastasis and poor survival of patients with cancer. The aim of the present study was to investigate the relationship between ezrin expression and the expression of HER2, p53, and Ki-67 as well as clinicopathological factors in SGCs. For this purpose, we used immunohistochemistry to analyze the expression of these proteins in tissue microarrays prepared from formalin-fixed, paraffin-embedded primary tumor tissues of 221 patients with SGCs. Using receiver operating characteristic curves, we determined cut-off values of 30% and 5.0% for high expression of ezrin and Ki-67, respectively. High ezrin expression detected in samples from 63 (28.5%) patients with SGCs significantly correlated with male sex, high-grade histopathology, high Ki-67 labeling index, HER2 overexpression, aberrant expression of p53, and distant metastasis. Multivariate analysis demonstrated that high ezrin expression was an independent prognostic factor for shorter overall survival (hazard ratio, 2.11 [1.09-4.05]; P=.027). Furthermore, concomitant high expression of ezrin and HER2 overexpression correlated significantly with shorter disease-free survival and overall survival as well as a high incidence of distant metastasis (P<.001). These findings indicate that ezrin and HER2 expression in patients with SGCs represents a high-grade histopathological subtype that requires adjuvant therapy, including molecularly targeted therapies, to decrease the risk of subsequent metastasis.

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.

Carcinoma ex pleomorphic adenoma originating from ectopic salivary gland in the neck region: case report

Carcinoma ex pleomorphic adenoma (CEPA) is the malignant salivary gland tumor originating from primary (de novo) or recurrent pleomorphic adenoma. Although parotid gland is the most common site, it can also be seen in submandibular gland or minor salivary glands. It can be seen rarely in head and neck region, such as oral cavity, trachea, nasal cavity and lacrimal gland. Although pleomorphic adenoma cases originating from ectopic salivary gland tissue in the neck region are present in the English literature, there is no published pleomorphic adenoma ex carcinoma case. In this case report we presented a CEPA as a 7.5 cm long neck mass in a 72-year-old woman originating from the submandibular region apart from submandibular gland. Difficulties in diagnosis and way to appropriate treatment are discussed with current literature.

Comparative analysis of antioxidative systems in malignant and benign brain tumours

OBJECTIVES

Comparison of redox conditions in malignant and benign tumours is essential for understanding the role of reactive oxygen species in the pathophysiology of aggressive cancer profiles. Here we compare antioxidative systems in highly malignant brain tumour - glioblastoma multiforme (GBM), and in meningioma, a benign brain tumour.

METHODS

Tumour tissues and blood of 67 GBM patients (mean age: 52.9 ± 11.5 years) and 67 meningioma patients (59.2 ± 10.2 years), and blood of 30 control subjects (50.8 ± 12.8 years) were analysed via biochemical assays.

RESULTS

Components of glutathione system, which is responsible for H2O2 removal, showed lower activity/level in GBM: glutathione peroxidase (GBM: 9.90 ± 0.22; meningioma: 11.78 ± 0.23 U/mg of proteins; P < 0.001), glutathione reductase (GBM: 3.83 ± 0.13; meningioma: 4.67 ± 0.11 U/mg of proteins; P < 0.001), and glutathione (GBM: 6.70 ± 0.12; meningioma: 7.58 ± 0.14 μmol/g of tissue; P < 0.001). In contrast, the rank order of glutathione reductase activity and glutathione level in erythrocytes was: GBM > meningioma > control. Superoxide dismutase and catalase activities were lower in the blood of cancer patients compared to controls.

DISCUSSION

Cells of malignant brain tumour show down-regulated antioxidative system which might result in increased levels of H2O2 compared to benign tumour tissue.

The EGF signaling pathway influences cell migration and the secretion of metalloproteinases by myoepithelial cells in pleomorphic adenoma

During tumor development, benign neoplastic cells are influenced by the expression of cytokines, growth factors, and proteases present in the tumor microenvironment. Epidermal growth factor (EGF) is the most studied growth factor and is considered important for cell proliferation and migration. Metalloproteinases (MMPs) are also involved in tumor progression. The present study aimed to analyze the proliferation, viability and migration index of pleomorphic adenoma myoepithelial cells, in addition to the secretion of MMPs with EGF supplementation. Benign myoepithelial cells were cultured with two different EGF doses (5 and 10 ng/ml), and the influence of EGF on cell proliferation and viability, using trypan blue and MTT assays, respectively, after 24, 48, and 72 h, was evaluated. To analyze cellular morphology, hematoxylin-eosin staining and indirect immunofluorescence using the anti-vimentin antibody, was performed. In vitro migration assays were performed in Transwell chambers with an 8-μm pore covered with Matrigel and supplemented with 5 or 10 ng/ml of EGF, after 96 h. After 4 days of cell culture, ELISA was performed to determine the MMP-2 and MMP-13 levels. One-way analysis of variance (ANOVA) with post hoc Tukey test was applied, with a significance level of 0.05. The results revealed that EGF influences myoepithelial cell morphology, without alteration of proliferation and viability. The migration assay showed that EGF increased the mean index from 16 % in the control group to 40 and 76 % for 5 and 10 ng/ml of EGF, respectively. ELISA revealed that when the cells were supplemented with either of the EGF doses, an increase in MMP-2 levels was observed when compared with the control group (C). This study concludes that EGF aids in the production of MMP-2, which favors the dissolution of the basement membrane, contributing to cell migration and tumor progression, hence permitting contact between the myoepithelial cells and stroma.

Peroxiredoxin overexpression in MCF-7 breast cancer cells and regulation by cell proliferation and oxidative stress

Peroxiredoxins are thiol-specific antioxidant proteins that protect cells from ROS-induced cell death and are elevated in several cancers. We found that five of the six mammalian peroxiredoxins are overexpressed in MCF-7 breast cancer cells at the mRNA and protein levels, compared to noncancerous MCF-10A cells. Inhibition of MCF-7 proliferation reduced the levels of several peroxiredoxins. In contrast, all six proteins were strongly and transiently induced in MCF-7 cells by H₂O₂. These data suggest that coordinate overexpression of peroxiredoxins may be an important cancer cell adaptation, and that these proteins can be regulated by cell proliferation and oxidative stress.

Expression of the chemokine CCL28 in pleomorphic adenoma and adenolymphoma of the human salivary glands

Recent studies have proposed that the chemokine CCL28 is constitutively expressed by epithelial cells in salivary glands and play an important role in lymphocyte trafficking in oral immunity. To date, there is little information on the expression pattern of CCL28 in salivary gland tumors. The purpose of this study was to determine the expression of CCL28 in pleomorphic adenoma and adenolymphoma and to evaluate its potential function in regulating oral carcinogenesis. Immunohistochemical reactivity revealed CCL28 protein expression in the cytoplasm of acinar epithelial cells, both in tumorous tissues and normal adjacent tissues. The level of CCL28 mRNA was markedly reduced in 70% (28/40) of pleomorphic adenomas, and in 81% (26/32) of adenolymphomas, compared to the normal adjacent tissue. CCL28 protein expression was significantly lower in pleomorphic adenomas (P=0.0027, n=40) and in adenolymphomas (P=0.0003, n=32) compared to their normal adjacent tissues. Additionally, the CCL28 protein levels in saliva in the aforementioned patients were lower than those in healthy volunteers. Our study indicated that the reduced expression of CCL28 could possibly be a strategy by recruiting fewer antitumor immunocompetent cells to salivary glands. The expression and secretion of CCL28 may be associated with the pathogenesis of pleomorphic adenoma and adenolymphoma.

Carcinoma ex pleomorphic adenoma of the salivary glands: distinct clinicopathologic features and immunoprofiles between subgroups according to cellular differentiation

In carcinoma ex pleomorphic adenoma (CXPA), pleomorphic adenoma (PA) and diverse carcinoma components showing luminal (ductal) or non-luminal (myoepithelial) differentiation coexist. To elucidate the clinicopathological implications of cellular differentiation in CXPA and the potential role of p53, vascular endothelial growth factor (VEGF), c-erbB-2, c-kit, and glucose transporter 1 (Glut-1) in carcinogenesis, we analyzed 11 CXPAs with luminal differentiation (CXPAs-LD) and 6 CXPAs with non-luminal differentiation (CXPAs-NLD) and compared protein expressions in residual PAs and carcinomas by immunohistochemistry. Among the CXPAs-LD, 5 were invasive and 8 were histologically high-grade tumors. The 5-year survival rate was 72.7%. P53, c-erbB-2, VEGF, and Glut-1 were more immunoreactive in carcinoma components than in PAs (P = 0.008, 0.004, 0.002, and 0.024, respectively); c-erbB-2 overexpression was associated with high histological grade (P = 0.024). Carcinoma components frequently lacked c-kit expression (P = 0.009). CXPAs-NLD were all low-grade and invasive with a larger mean tumor size (5.2 cm) than CXPAs-LD (3.3 cm) (P = 0.040). The patients remained disease-free without significant immunohistochemical expression. The immunoprofiles and clinical course of CXPA differed according to cellular differentiation. Therefore, it is important to report the histological subtype and to assess potential biomarkers in diagnostic and therapeutic trials.

Carcinoma ex pleomorphic adenoma: a comprehensive review of clinical, pathological and molecular data

Carcinoma ex pleomorphic adenoma (Ca ex PA) is a carcinoma arising from a primary or recurrent benign pleomorphic adenoma. It often poses a diagnostic challenge to clinicians and pathologists. This study intends to review the literature and highlight the current clinical and molecular perspectives about this entity. The most common clinical presentation of CA ex PA is of a firm mass in the parotid gland. The proportion of adenoma and carcinoma components determines the macroscopic features of this neoplasm. The entity is difficult to diagnose pre-operatively. Pathologic assessment is the gold standard for making the diagnosis. Treatment for Ca ex PA often involves an ablative surgical procedure which may be followed by radiotherapy. Overall, patients with Ca ex PA have a poor prognosis. Accurate diagnosis and aggressive surgical management of patients presenting with Ca ex PA can increase their survival rates. Molecular studies have revealed that the development of Ca ex PA follows a multi-step model of carcinogenesis, with the progressive loss of heterozygosity at chromosomal arms 8q, then 12q and finally 17p. There are specific candidate genes in these regions that are associated with particular stages in the progression of Ca ex PA. In addition, many genes which regulate tumour suppression, cell cycle control, growth factors and cell-cell adhesion play a role in the development and progression of Ca ex PA. It is hopeful that these molecular data can give clues for the diagnosis and management of the disease.

Immunohistochemical Expression of p53 in Pleomorphic Adenoma and Carcinoma Ex Pleomorphic Adenoma

Context. Immunohistochemical stains for p53 are used as a diagnostic marker associated with malignancy in several histologic types of salivary gland tumors. This marker may be useful in differentiating pleomorphic adenoma (PA) from carcinoma ex pleomorphic adenoma (CPA), as these tumors are often difficult to distinguish on the basis of morphology alone. Objective. to evaluate whatever inactivation of tumor suppressor gene (p53) increases with the tumor progression from normal salivary tissue to PA and eventually CPA. Design. Paraffin blocks of 29 cases of PA, which were surrounded by normal parotid gland, and 27 cases of carcinoma ex pleomorphic adenoma were retrieved and validated. In all cases of carcinoma ex pleomorphic adenoma, a PA “ghost” was identified, and the malignant element was either undifferentiated carcinoma or adenocarcinoma. Results. The results showed negative nuclear expression of P53 in normal parotid gland. Nuclear P53 was expressed strongly in 6/29 (20.7%) pleomorphic salivary adenoma and 10/27 (37%) carcinoma ex pleomorphic adenoma. Conclusion. Our data suggest that inactivation of p53 may play an important role in the evolution of pleomorphic salivary adenoma and carcinoma ex pleomorphic adenoma.

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.

FGF-2, TGFbeta-1, PDGF-A and respective receptors expression in pleomorphic adenoma myoepithelial cells: an in vivo and in vitro study

Myoepithelial cells have an important role in salivary gland tumor development, contributing to a low grade of aggressiveness of these tumors. Normal myoepithelial cells are known by their suppressor function presenting increased expression of extracellular matrix genes and protease inhibitors. The importance of stromal cells and growth factors during tumor initiation and progression has been highlighted by recent literature. Many tumors result from the alteration of paracrine growth factors pathways. Growth factors mediate a wide variety of biological processes such as development, tissue repair and tumorigenesis, and also contribute to cellular proliferation and transformation in neoplastic cells.

OBJECTIVES

This study evaluated the expression of fibroblast growth factor-2 (FGF-2), transforming growth factor beta-1 (TGFbeta-1), platelet-derived growth factor-A (PDGF-A) and their respective receptors (FGFR-1, FGFR-2, TGFbetaR-II and PDGFR-alpha) in myoepithelial cells from pleomorphic adenomas (PA) by in vivo and in vitro experiments.

MATERIAL AND METHODS

Serial sections were obtained from paraffin-embedded PA samples obtained from the school's files. Myoepithelial cells were obtained from explants of PA tumors provided by surgery from different donors. Immunohistochemistry, cell culture and immunofluorescence assays were used to evaluate growth factor expression.

RESULTS

The present findings demonstrated that myoepithelial cells from PA were mainly positive to FGF-2 and FGFR-1 by immunohistochemistry and immunofluorescence. PDGF-A and PDGFR-alpha had moderate expression by immunohistochemistry and presented punctated deposits throughout cytoplasm of myoepithelial cells. FGFR-2, TGFbeta-1 and TGFbetaR-II were negative in all samples.

CONCLUSIONS

These data suggested that FGF-2 compared to the other studied growth factors has an important role in PA benign myoepithelial cells, probably contributing to proliferation of these cells through the FGFR-1.