Oncogenic DNA viruses found in salivary gland tumors

BACKGROUND

Previous investigations studying the association of DNA viruses with salivary gland tumors (SGTs) have led to conflicting results. The aim of this study was to determine the prevalence of different DNA viruses by using a highly sensitive assay in a multi-center series of over 100 fresh frozen salivary gland samples.

METHODS

DNA was isolated from 84 SGTs (80 parotid tumors and 4 submandibular gland tumors) and 28 normal salivary tissue samples from 85 patients in Northeast Italy. Using a highly sensitive type-specific multiplex genotyping assay, we analyzed the samples for the presence of DNA from 62 different viruses including 47 papillomaviruses, 10 polyomaviruses, and 5 herpesviruses.

RESULTS

We observed a high prevalence of beta human papillomavirus DNA in malignant tumors. In contrast, polyomavirus DNA was present in benign, malignant, and non-tumor control samples. Most striking was the significant distribution of herpesvirus DNA in the SGT samples, in particular the high prevalence of Epstein-Barr type 1 and type 2 DNA in Warthin's tumor samples.

CONCLUSION

Our data provides evidence for the presence of DNA viruses in SGTs. Mechanistic studies are needed to further attribute tumor formation to these viruses.

Primary lymphoepithelioma-like carcinoma of salivary glands: a clinicopathological study of 21 cases

Lymphoepithelioma-like carcinoma (LELC) of salivary glands is a rare kind tumor. In this study, the authors evaluated 21 patients with LELC of salivary glands who had long-term follow-up. Clinical characteristics, Epstein-Barr virus (EBV) infection, immunohistochemical features, oncoprotein expression, treatments, and outcomes were analyzed. All patients were Chinese. Their ages ranged from 20 to 73 years. All tumors showed the typical syncytial growth pattern of undifferentiated epithelial cells with a significant lymphocyte reaction. All of patients were found by in situ hybridization to have the EBV genome. All tumors showed positive immunostaining of AE1/AE3, CK5/6 and p63. Nearly all cases had bcl-2 oncoprotein expression, but the detection rate of p53, and c-erb B-2 expression was extremely low. LELC of salivary glands is a distinct entity of salivary cancer. LELC of salivary glands can receive multimodality treatment and has a better prognosis similar to that of nasopharyngeal carcinoma.

[Clinical analysis of sixteen cases of lymphoepithelial carcinoma of salivary gland]

BACKGROUND & OBJECTIVE

Lymphoepithelial carcinoma of salivary gland is a rare and special kind of malignant tumor, and has seldom been reported. This study was to summarize the clinical features, treatment and curative effect of this disease according to our experiences.

METHODS

Clinical data of 16 patients with pathologically confirmed primary lymphoepithelial carcinoma of salivary gland, treated in Cancer Center of Sun Yat-sen University from Jan. 1990 to Sep. 2004, were retrospectively analyzed, and survival analysis was performed with Kaplan-Meier method.

RESULTS

The 16 patients with lymphoepithelial carcinoma of salivary gland accounted for 3.6% of all the patients diagnosed as malignant tumors of salivary gland simultaneously in our center. All patients had tumors occurred in unilateral gland, aged 15-57 years, with the female to male ratio of 1:1. All patients were from southern China. Except for 1 patient, the rest 15 had Epstein-Barr virus (EBV) serological tests. The positive rates of EBV-VCA-IgA, EBV-EA-IgA, and EBV-DNA enzyme were 93.3%, 66.7%, and 86.7%, respectively. All patients were treated with surgery, of which 9 received surgery only, 5 received surgery plus postoperative radiotherapy, 1 received surgery plus postoperative chemoradiotherapy, 1 received surgery plus chemotherapy. Four (25.0%) patients had postoperative pathology-proved ipsilateral cervical lymph node metastasis. The 1-, 3-, and 5-year survival rates of the 16 patients were 86.15%, 48.46%, and 24.23%.

CONCLUSIONS

Although lymphoepithelial carcinoma of salivary gland is poorly differentiated, the prognosis of this disease is good. Complete resection plus postoperative radiotherapy is possibly accommodating.

Epstein-Barr virus infection in salivary gland tumors in children and young adults

BACKGROUND

Epstein-Barr virus (EBV) infection has been implicated in the pathogenesis of certain subtypes of salivary gland tumors in the adult population. However, to the authors' knowledge its role in pediatric salivary gland tumors, a rare disease, has not been explored previously.

METHODS

Thirteen cases of primary tumors of the salivary gland occurring in children were retrieved from the tumor registry at the St. Jude Children's Research Hospital in Memphis, Tennessee. Clinical data were analyzed from the medical records and formalin fixed, paraffin embedded tumor tissues were examined by the in situ hybridization (ISH) technique for the presence of latent EBV infection.

RESULTS

Twelve of 13 tumors originated from the parotid gland and 1 originated from the submandibular gland. Mucoepidermoid carcinoma was the predominant tumor type; it was observed in seven patients, rhabdomyosarcoma was the diagnosis in three patients, acinic cell carcinoma was noted in two patients, and malignant fibrous histiocytoma was diagnosed in one patient. The ages of the patients ranged from 4.1-29.2 years, with a median age of 11 years. The outcome was excellent with all patients alive and free of disease at the time of last follow-up. The ISH tested negative in all tumor samples.

CONCLUSIONS

Based on the results of the current study, EBV infection does not appear to play a major role in the pathogenesis of pediatric salivary gland tumors.

Lymphoepithelioma-like salivary gland carcinoma in Taiwan: a clinicopathological study of nine cases demonstrating a strong association with Epstein-Barr virus

AIMS

Lymphoepithelioma-like carcinoma (LELC) of the salivary glands is a rather rare tumour. Previous studies have shown its strong association with Epstein-Barr virus (EBV) among Chinese and Eskimos. We tested this observation with nine Chinese patients with salivary gland LELC in Taiwan including one with coexisting nasopharyngeal carcinoma (NPC) and studied the prognostic significance of their histopathological features.

METHODS AND RESULTS

This series showed a predilection for female patients and parotid glands with a median age of 50 years. Three patients died 18.5-26 months after the diagnosis including the case with NPC. Six patients were alive without recurrence for 14-45 months with a median follow-up of 34.5 months. Histopathologically, the tumours showed either lobular or diffuse growth pattern. Granulomas and/or germinal centres were observed in most cases and both B- and T-cells were found in the lymphoid infiltrates, indicating that the salivary gland LELC was capable of inducing a strong host immune reaction. Microscopic growth pattern, lymph node metastasis, and presence or absence of granulomas and/or germinal centres seemed to be important prognostic factors. Both salivary gland LELC and NPC shared similar histopathological appearance and positive immunostaining for epithelial membrane antigen and cytokeratin AE1 but not AE3. Granulomas and amyloid might occur in both tumours. A nasopharyngeal examination is indicated in patients with salivary gland LELC to exclude the possibility of coexisting or metastatic NPC. All nine cases showed positive nuclear signals for EBV-encoded RNA by in situ hybridization including the case with NPC.

CONCLUSIONS

Our study and the previously published studies show that the association of salivary gland LELC and EBV is strongly related to racial and geographical factors.

Epstein-Barr virus (EBV) infection in salivary gland tumors: lytic EBV infection in nonmalignant epithelial cells surrounded by EBV-positive T-lymphoma cells

To elucidate the association of Epstein-Barr virus (EBV) and salivary gland tumors, 114 cases of tumors of major salivary glands were investigated. EBV DNA was detected in all 6 cases of undifferentiated carcinoma and all 3 cases of T-cell lymphoma, but not in other tumor tissues. In situ hybridization studies for EBV DNA and EBV-encoded small RNA 1 (EBER1) showed specific localization of the EBV sequences to the undifferentiated carcinoma cells and T-lymphoma cells. Moreover, intense DNA signals were detected on nonneoplastic epithelial cells of T-lymphoma tissues. These epithelial cells were negative for EBER1 and expressed BZLF1, BALF2, and gp350/220 proteins associated with virus production. In contrast, nonmalignant epithelial cells surrounded by undifferentiated carcinoma cells showed no evidence of EBV infection or virus replication. These results indicate that there is an unusual association of salivary gland T-cell lymphomas with lytic EBV replication of nonmalignant epithelial cells.

Expression of Epstein-Barr virus in carcinomas of major salivary glands: a strong association with lymphoepithelioma-like carcinoma

To elucidate the role of Epstein-Barr virus (EBV) in salivary gland carcinomas, 56 cases of carcinomas of major salivary glands were investigated. These included 14 mucoepidermoid carcinomas, 13 adenoid cystic carcinomas, seven malignant mixed tumors, four adenocarcinomas, four salivary duct carcinomas, two acinic cell carcinomas, two undifferentiated carcinomas without lymphoid stroma, seven lymphoepithelioma-like carcinomas (LELCs), two squamous cell carcinomas, and one small cell carcinoma. EBV transcripts were examined by in situ hybridization using digoxigenin-labeled oligonucleotide antisense probe for EBV-encoded RNA 1 (EBER1) on formalin-fixed paraffin-embedded tissue sections. EBER1 was detected in the malignant epithelial cells in all seven cases of LELC, but not in any of the other carcinomas and the neighboring normal salivary gland tissue. Because all the EBV-negative cases showed satisfactory labeling with the poly d(T) probe, the negative reaction with EBER1 was unlikely to be caused by poor RNA preservation in the tissues. The seven cases of LELC, which were histologically indistinguishable from undifferentiated nasopharyngeal carcinoma (NPC), had a disease-free 4-year survival rate of 85.7%. The results suggest that LELC of the salivary gland in Taiwanese Chinese may share similar EBV-related pathogenesis with that of NPC.