Comparison of integrin alpha chain expression in benign and malignant salivary gland tumors

Cell adhesion molecules' altered profile in benign and malignant salivary gland tumors. The paradigm of beta4-integrin, desmoglein-2, ICAM-1 and CD44s

Background

Alterations in intercellular and cell-extracellular matrix connections contribute to tumour development. This study investigates the expression of specific cell adhesion molecules (CAMs) in salivary gland tumors (SGTs).

Methods

Formalin–fixed, paraffin– embedded tissue specimens of different types of 34 benign and 31 malignant SGTs and normal salivary glands were studied using Envision/HRP immunohistochemical technique for Desmoglein-2 (Dsg-2), beta4-integrin, CD44s and ICAM-1. Intensity of staining was evaluated in a semi-quantitative manner. Results were analyzed using Kendall’s τ and Spearman’s ρ as correlation criteria.

Results

Dsg-2 in intercellular space, beta4-integrin in cell-basal membrane, and CD44s in both types of contacts were strongly expressed in normal acinar and ductal cells, whereas ICAM-1 was expressed only at the endothelium and sparse stromal cells and monocytes. Strong correlation was found between Dsg-2 expression in adenomas and controls and between adenocarcinomas and controls. In adenomas, a distinct cytoplasmic presence of Dsg-2 was observed in addition to the usual membranous expression, with decreased expression in comparison with normal tissue. In malignant SGTs, Dsg-2 expression was absent. In most SGTs, beta4-integrin was expressed also with a distinct pattern, involving the cytoplasm and the unpolarised membrane, while CD44 was found only on the membrane. Strong correlation between beta4-integrin expression in adenomas and controls was noted, while CD44 expression was found to be correlated significantly between adenocarcinomas and controls (p < 0.001). Regarding ICAM-1, its expression was found increased in adenomas, with non-specific distribution in malignant SGTs and strong correlation between the histological subtypes and controls (p < 0.001).

Conclusion

The different expression profile of CAMs in SGTs could possibly suggest a role on their pathogenesis, representing a model of how neoplastic cells can take advantage of normal tissue architecture and cell-extracellular matrix interactions.

Immunoexpression of integrins in ameloblastoma, adenomatoid odontogenic tumor, and human tooth germs

The expression of integrins alpha2beta1, alpha3beta1, and alpha5beta1 in 30 ameloblastomas (20 solid and 10 unicystic tumors), 12 adenomatoid odontogenic tumors (AOTs), and 5 human tooth germs in different stages of odontogenesis was analyzed. The distribution, location, pattern, and intensity of immunohistochemical expression were evaluated. Intensity was analyzed using scores (0 = absence, 1 = weak staining, and 2 = strong staining). No difference in the immunoexpression of the integrins was observed between solid and unicystic ameloblastomas. When these two ameloblastoma types were pooled into a single group, the following significant differences were found: immunoexpression of integrin alpha2beta1 was stronger in ameloblastomas than in AOTs and tooth germs, and the expression of integrin alpha5beta1 was stronger in ameloblastomas than in AOTs. The lack of detection of integrin alpha3beta1 in tooth germs and its detection in the odontogenic tumors studied suggest that this integrin might be used as a marker of neoplastic transformation in odontogenic tissues.

Ameloblastoma and adenomatoid odontogenic tumor: the role of α2β1, α3β1, and α5β1 integrins in local invasiveness and architectural characteristics

Ameloblastoma is an odontogenic neoplasm characterized by local invasiveness and a tendency toward recurrence, whereas adenomatoid odontogenic tumor (AOT) is an indolent neoplasm. The objective of the present study was to immunohistochemically analyze the role of alpha2beta1, alpha3beta1, and alpha5beta1 integrins in the cellular events and cell-matrix interactions that occur in these tumors and their consequent repercussions on the architectural arrangement and biologic behavior of these lesions. Paraffin-embedded specimens from 30 ameloblastomas (20 solid and 10 unicystic tumors) and 12 AOTs were submitted to immunohistochemistry using the catalyzed signal amplification system. A difference in the pattern of integrin expression was observed between the various histologic types of ameloblastoma. No significant difference in labeling intensity was observed between unicystic and solid ameloblastomas, but comparison between ameloblastomas and AOT showed a significantly stronger expression of alpha5beta1 integrin in the former (P < .05). Our findings suggest an important role of the integrins studied in the architectural characteristics of ameloblastomas and AOTs and a possible participation of alpha5beta1 integrin in the mechanism of local invasion of ameloblastomas.

Relationship between cancer and oral pemphigoid patients with antibodies to α6-integrin

BACKGROUND

Mucous membrane pemphigoid is an autoimmune mucocutaneous blistering disease. A subset, known as anti-epiligrin cicatricial pemphigoid is associated with a high risk for malignancy. Oral pemphigoid (OP) is limited to the oral cavity. The purpose of this study was to determine the association between malignancy and patients with OP with antibodies to alpha6-integrin subunit.

METHODS

We determined the incidence of cancer in 72 patients with OP and compared it to the expected incidence using age and sex-specific rates of malignancy in the National Cancer Institute's Surveillance, Epidemiology, and End Results (NCI SEER) Registry.

RESULTS

During a mean observation period of 9.1 years (range: 2.8-40), for 70, three OP patients developed malignancies. The expected number of cancers based on the NCI SEER Registry was 8.83. The relative risk for cancer in OP patients, with autoantibodies to alpha6-integrin, was 0.34 (95% CI, 0.07-0.99, P < 0.05).

CONCLUSION

It appears that patients with OP, with antibodies to alpha6, may have a possible reduced relative risk for developing cancer.

Integrins in metastatic adenoid cystic carcinoma

Adenoid cystic carcinoma exhibits a diverse clinical behaviour from very localised invasion to widespread metastatases. Recently two adenoid cystic carcinoma cells lines have been isolated and cultured which distinctly show either a low metastatic tendency (Acc-2) or a highly metastatic behaviour (Acc-M). It was hypothesised that these two types of behaviour may at least in part be explained by the different integrin profile on the cells' surface membrane. The integrins represent the largest known family of cell adhesion molecules and a number of tumour cell processes have been shown to be dependant on their integrin expression. Adenoid cystic carcinoma cells of both types were obtained and successfully cultured. These were then subjected to integrin analysis by a number of monoclonal antibodies to alpha(1), alpha(2), alpha(3), alpha(v), alpha(6), beta(1), alpha(v)beta6, alpha(v)beta4 using a fluorescence activated cell sorter. Although there was an apparent difference of integrin expression in the Acc-M group as compared to the Acc-2 group, this was not statistically significant. It is still possible though, that this might account for the differences in behaviour of the two cell lines, and the relationship between integrins, and invasion and metastases in other tumours is discussed. The pattern of integrin expression in Acc may be prognostically significant and useful for treatment planning in the future.

Expression patterns of integrins on pleomorphic adenoma and adenoid cystic carcinoma: study on specimens and in vitro investigation of the effects of extracellular matrix on the expression of these adhesion molecules

BACKGROUND

Pleomorphic adenoma (PA) and adenoid cystic carcinoma (ACC) are neoplasms of distinct behaviour, showing similar origin, cell components and marked presence of extracellular matrix (ECM). Interactions between cells and ECM are important in the biology of tumours, being partially mediated by integrins. This study investigated these interactions on PA and ACC using paraffin-embedded tissue and an in vitro model of these conditions.

METHODS

Expression of integrins in paraffin-embedded samples was assessed by immunohistochemistry. Cells from PA and ACC were characterized using immunofluorescence, and integrin patterns of expression were investigated on cells cultivated on different ECM proteins.

RESULTS

Luminal cells of both PA and ACC were more intensely positive for integrins than myoepithelial cells. In vitro studies revealed that PA cells expressed more integrins than ACC cells regardless the ECM protein present.

CONCLUSIONS

This study revealed particular patterns of integrin expression in both specimens and in vitro models of PA and ACC. This might prove useful for a better understanding of the biology of these lesions.

Salivary gland tumours: immunoexpression of integrins beta 1, beta 3 and beta 4

BACKGROUND

Integrins, heterodimeric transmembranic adhesion molecules composed of alpha and beta subunits, have been implicated in normal and neoplastic biological processes. We investigated the patterns of expression of integrins subunits beta 1, beta 3 and beta 4 in neoplasms derived from the terminal segment of salivary glands in order to understand their expression patterns in the different structures of these tumours.

METHODS

Immunohistochemistry using 'catalized signal amplification' (CSA) detection system was applied to paraffin-embedded specimens of polymorphous low-grade adenocarcinoma, adenoid cystic carcinoma and acinic cell carcinoma. Normal salivary glands were used as controls.

RESULTS

Immunoexpression of integrins showed that neoplastic structures of the tumours studied tend to mimic the patterns seen in the normal structures of salivary glands from which they are derived. Anaplastic cells were negative for all integrins.

CONCLUSIONS

This study revealed detailed topography of integrins in malignant tumours derived from intercalated acinar segment of salivary gland and this might be useful in the diagnosis of these lesions, especially of fine-needle aspiration (FNA) products or small specimens derived form incisional biopsies.