A case of Epstein-Barr Virus (EBV)-associated thymic carcinoid and investigation of existence of EBV-infected cells in thymus and thymic tumors

Detection of Epstein-Barr virus infection in thymic epithelial tumors by nested PCR and Epstein-Barr-encoded RNA ISH

BACKGROUND

Epstein-Barr virus (EBV) is well known to be associated with a lot of tumors, including lymphoma, nasopharyngeal carcinoma, EBV-associated gastric carcinoma, and some other carcinomas with similar lymphoepithelioma-like features. However, the association between EBV and thymic epithelial tumors (TETs) is inconclusive as reports in this regard are not entirely consistent and the methods employed are of different sensitivity and specificity. The geographical difference of the patients is also one of the reasons for the different points of view.

METHODS

In our study, we examined 72 thymomas, including 3 cases of type A thymomas, 27 cases of type AB, 6 cases of type B1, 26 cases of type B2 and 10 cases of type B3 thymomas, and 15 thymic carcinomas to detect the viral genome at both DNA and RNA levels. The genome DNA of fresh tissues was first screened by nested polymerase chain reaction (PCR), which could be regarded as the most sensitive method to detect small amounts of DNA. Then all the tissue blocks were further submitted for viral localization by Epstein-Barr-encoded RNA (EBER) ISH. Group parameters were assessed using the chi-square test at a significance level of p < 0.05.

RESULTS

Nested PCR results showed that none of type A, eight (29.6%) type AB, one (16.7%) type B1, fifteen (57.7%) type B2, and four (40.0%) type B3 were positive for EBV genome. However, none of them detected EBER expression except for one case of type B2 thymoma. Fourteen (93.3%) thymic carcinomas were positive for EBV by nested PCR, of which three displayed weak nuclear signals within the tumor cells by EBER ISH.

CONCLUSIONS

These results showed that nested PCR was a sensitive method for screening the EBV genome in thymic epithelial tumors. As the malignancy of thymoma increases, the rate of EBV infection became higher. Thymic carcinomas were well associated with the Epstein-Barr virus.There was significant association between the EBV infection rate and thymoma type (p < 0.05). We further analyzed the association between EBV infection and myasthenia gravis. However, it showed no significant difference(p = 0.2754), although the EBV infection rate was higher in the thymomas with myasthenia gravis.

Epstein-Barr Virus in Myasthenia Gravis: Key Contributing Factor Linking Innate Immunity with B-Cell-Mediated Autoimmunity

Epstein-Barr virus (EBV), a common human herpes virus latently infecting most of the world’s population with periodic reactivations, is the main environmental factor suspected to trigger and/or sustain autoimmunity by its ability to disrupt B-cell tolerance checkpoints. Myasthenia gravis (MG) is a prototypic autoimmune disorder, mostly caused by autoantibodies to acetylcholine receptor (AChR) of the neuromuscular junction, which cause muscle weakness and fatigability. Most patients display hyperplastic thymus, characterized by ectopic germinal center formation, chronic inflammation, exacerbated Toll-like receptor activation, and abnormal B-cell activation. After an overview on MG clinical features and intra-thymic pathogenesis, in the present chapter, we describe our main findings on EBV presence in MG thymuses, including hyperplastic and thymoma thymuses, in relationship with innate immunity activation and data from other autoimmune conditions. Our overall data strongly indicate a critical contribution of EBV to innate immune dysregulation and sustained B-cell-mediated autoimmune response in the pathological thymus of MG patients.

Viral infection in thymoma and thymic tumors with autoimmune diseases

A thymoma is a type of thymic tumor which is rarely malignant that is frequently reported in adult patients. A number of thymoma-related immune disorders are observed including autoimmune diseases, which suggests a strong connection between thymoma development and immunological mechanisms. Characterized by association with humoral and cellular immunodeficiency, thymoma patients are susceptible to opportunistic infections by environmental factors. Recent reports have suggested that viral infection may play a role in the etiological mechanisms of thymoma development associated with dysregulated immunity. In this review, we summarize the case reports and studies related to viral infection, such as CMV, EBV and HSV, that probably play a part in the pathogenesis of thymoma and related diseases. Furthermore, we demonstrate the underlying mechanisms by which viruses may induce the occurrence of thymoma with autoimmune diseases. Lastly, we discuss the potential application of antiviral therapy in the treatment of thymic diseases.

Prevalence of Epstein-Barr virus (EBV) in Iranian Breast Carcinoma Patients

Introduction:

Breast cancer (BC) is the most common malignancy affecting females worldwide. Various risk factors play a role in the developing of BC. Infectious agents like viruses have been proposed for this cancer and Epstein-Barr virus (EBV) is a widely researched candidate virus. This study detects the presence of EBV-DNA in breast cancer patients.

Methods:

The study was conducted on 59 formalin-fixed paraffin-embedded (FFPE) tissue blocks samples of women with breast carcinoma and 11 non-neoplastic breast controls. The DNA was extracted for all the samples. Then detection of EBNA1 EBV was done by polymerase chain reaction (PCR).

Results:

EBV was detected in 6.7% (4/59) of patients while all breast control samples were negative. All patients with positive EBV-DNA were high tumor grades (II, and III). Also, they had a low level of educations.

Conclusions:

According to our findings, it can be suggested that EBV may have a potential role in breast cancer development. However, this study provides substantial but not conclusive evidence for the involvement of viruses in BC disease development. Therefore, future investigations are needed to elucidate the exact role of EBV in breast cancer.

Epstein-Barr virus in tumor-infiltrating B cells of myasthenia gravis thymoma: an innocent bystander or an autoimmunity mediator?

The thymus plays a key role in myasthenia gravis (MG), a B cell-mediated autoimmune disorder affecting neuromuscular junction. Most MG patients have thymic abnormalities, including hyperplasia and thymoma, a neoplasm of thymic epithelial cells. Epstein-Barr virus (EBV) is associated with autoimmune diseases and tumors. Recently, we showed EBV persistence and reactivation in hyperplastic MG thymuses, suggesting that EBV might contribute to intra-thymic B cell dysregulation in MG patients. Here, we investigated EBV involvement in thymoma-associated MG, by searching for EBV markers in MG (n=26) and non-MG (n=14) thymomas. EBV DNA and EBV-encoded small nuclear RNA (EBER) 1 transcript were detected in 14/26 (53.8%) and 22/26 (84.6%) MG thymomas, and only in 3 of 14 (21.4%) non-MG thymomas. Latent EBNA2 and late gp350/220 lytic transcripts were undetectable in all, but one, thymomas, and early lytic BZLF1 transcript was absent in all samples, suggesting that early infection events and EBV reactivation were very rare in thymomas. EBER1 and 2-positive cells were detected in MG, but not in non-MG, thymomas, as well as cells expressing EBV latency proteins (EBNA1, LMP1, LMP2A), that were mainly of B cell phenotype, indicating EBV association with MG rather than with thymoma. Toll-like receptor (TLR) 3 transcriptional levels were higher in MG than non-MG thymomas and positively correlated with EBER1 levels, suggesting a role for EBERs in TLR3 activation. Our findings show that EBV is commonly present in thymoma-infiltrating B cells of myasthenic patients, indicating a contribution of EBV to B cell-mediated autoreactivity in MG associated with thymic tumor.

Lymphoepithelioma-like carcinoma of ureter-a rare case report and review of the literature

Lymphoepithelioma-like carcinoma (LELC) is best known to occur in the nasopharynx. When LELC occurs in the urinary tract, this extremely rare neoplasm most commonly affects the bladder but has also been reported in the renal pelvis, ureter, prostate [1], and urethra [2]. We present a case of LELC arising in the right proximal ureter of a 64-year-old male patient with hydronephrosis and nausea. Computed tomography demonstrated right ureter tumor. On biopsy, the patient was diagnosed with infiltrating urothelial carcinoma. An operation consisting of right nephroureterectomy and bladder cuff removal was carried out. The pathologic examination showed pure subtype of LELC, pT3N0. Unlike lymphoepithelioma in the nasopharynx, immunohistochemical analysis of this urinary LELC was negative for the Epstein-Barr virus. No disease progression was noted at 6 months' follow-up. Only eight previous cases of LELC involving the ureter have been reported, and a review of the available literature and a summary of ureter cases are presented here. This is the first report of a ureteral LELC case and third urothelial LELC cases [3] in Taiwan.

Lymphoepithelioma-like hepatocellular carcinoma: A case report and a review of the literature

Lymphoepithelioma is a particular form of undifferentiated carcinoma, characterized by a prominent lymphoid stroma, originally described in the nasopharynx. Lymphoid stroma-rich carcinomas arising in other organs have been termed lymphoepithelioma-like carcinoma (LELC). In the liver, primary LELCs are very rare, and the majority has been identified as cholangiocarcinomas. Here a rare case of lymphoepithelioma-like hepatocellular carcinoma (HCC) is described. A 47-year old woman presented with abdominal pain. Ultrasonography revealed a liver nodule, 2.2 cm in diameter, localized in the right lobe, adjacent to the gallbladder. Viral markers for hepatic B virus (HBV), hepatic C virus (HCV) and Epstein-Barr virus (EBV) were negative. The nodule was hypoechogenic. The patient underwent surgery, with resection of the nodule. Histology showed hepatocellular carcinoma, characterized by a prominent lymphoid infiltrate. At immunocytochemistry, tumor cells were reactive for Hep Par1 and glypican 3. Immunophenotyping of tumor infiltrating lymphocytes evidenced the predominance of CD8+ cytotoxic suppressor T cells. The postoperative clinical outcome was favorable and the patient was recurrence-free 15 mo after resection. This case, to the best of our knowledge, is the first reported non EBV and non cirrhosis-associated lymphoepithelioma-like hepatocellular carcinoma. The association between the lack of EBV infection, the absence of cirrhosis, a “cytotoxic profile” of the inflammatory infiltrate and a good prognosis could identify a variant of lymphoepithelioma-like HCC with a favorable clinical outcome.

Lymphoepithelioma-like carcinoma of the urinary tract: a clinicopathological study of 30 pure and mixed cases

We studied 28 cases of lymphoepithelioma-like carcinoma of the bladder, one case in the renal pelvis, and one in the urethra. The mean age of the patients was 67.6 years with 21 (70%) males. Seventeen cases (56.7%) were pure with the remaining mixed with other patterns of carcinoma, including invasive urothelial carcinoma (n=10), invasive adenocarcinoma (n=3), and squamous cell carcinoma (n=2). The surface demonstrated carcinoma in situ (CIS) in six cases, noninvasive high-grade papillary urothelial carcinoma in three cases, and in situ adenocarcinoma in one case. In 19/30 (66%) cases, there was a heavy lymphocytic infiltrate and in the remaining 11/30 (34%) cases a mixed inflammatory infiltrate. None of the 26 cases labeled for EBV-encoded RNA by in situ hybridization. Tumor stages at presentation were: seven cases T1 (23%); 14 cases T2 (47%); seven cases T3 (23%); and two cases T4 (7%). Treatment consisted of radical cystectomy in 13/30 cases (43%); partial cystectomy in 4/30 cases (13%); nephrectomy in one case (3%), and transurethral resection often followed by radiation or chemotherapy in 12/30 (40%) cases. The mean follow up for patients without progression was 31 months. Eight of 27 cases with follow-up (30%) cases had tumor recurrence, with seven patients having metastases. In cases treated with cystectomy, the 5-year actuarial recurrence-free risk was 59% (62 and 57%, for pure and mixed cases, respectively). Lymphoepithelioma-like carcinoma, whether in pure or mixed form, has a similar prognosis to ordinary urothelial carcinoma when treated by cystectomy. Of the three pure cases treated by chemotherapy, two were free of disease at 4 and 65 months and the third had recurrent disease at 17 months. Given the association of lymphoepithelioma-like carcinoma with urothelial carcinoma in 47% of our cases and its propensity for multifocality, partial cystectomy would typically be ill advised for lymphoepithelioma-like carcinoma.

Thymic lymphoepitheliomalike carcinoma in children: clinicopathologic features and molecular analysis

Thymic lymphoepitheliomalike carcinoma (LELC) in children is extremely rare and we report 2 such cases with molecular analysis of Epstein-Barr virus (EBV) and its encoded latent membrane protein-1 as well as a literature review. Both of our patients were male, presented with a huge anterior mediastinal mass, expired within a year after diagnosis despite treatment. There were altogether 9 cases of thymic LELC in children. Their common clinical features include a male predominance, large tumor size, advanced clinical stage, and poor clinical outcome. All cases were associated with EBV and nearly half developed concurrent hypertrophic osteoarthropathy (HOA). Thymic LELC in children is an aggressive EBV-associated malignant tumor frequently accompanied by HOA. We proposed that EBV might play a role in the development of HOA through the interactions of latent membrane protein-1, vascular endothelial growth factor, and cyclooxygenases-2.