Case report of lymphoepithelioma-like carcinoma of the lung--lymphoid population consisting of cytotoxic T cells in resting state

Epstein–Barr Virus Epithelial Cancers—A Comprehensive Understanding to Drive Novel Therapies

Epstein–Barr virus (EBV) is a ubiquitous oncovirus associated with specific epithelial and lymphoid cancers. Among the epithelial cancers, nasopharyngeal carcinoma (NPC), lymphoepithelioma-like carcinoma (LELC), and EBV-associated gastric cancers (EBVaGC) are the most common. The role of EBV in the pathogenesis of NPC and in the modulation of its tumour immune microenvironment (TIME) has been increasingly well described. Much less is known about the pathogenesis and tumour–microenvironment interactions in other EBV-associated epithelial cancers. Despite the expression of EBV-related viral oncoproteins and a generally immune-inflamed cancer subtype, EBV-associated epithelial cancers have limited systemic therapeutic options beyond conventional chemotherapy. Immune checkpoint inhibitors are effective only in a minority of these patients and even less efficacious with molecular targeting drugs. Here, we examine the key similarities and differences of NPC, LELC, and EBVaGC and comprehensively describe the clinical, pathological, and molecular characteristics of these cancers. A deeper comparative understanding of these EBV-driven cancers can potentially uncover targets in the tumour, TIME, and stroma, which may guide future drug development and cast light on resistance to immunotherapy.

Pathogenic Role of Epstein-Barr Virus in Lung Cancers

Human oncogenic viruses account for at least 12% of total cancer cases worldwide. Epstein–Barr virus (EBV) is the first identified human oncogenic virus and it alone causes ~200,000 cancer cases and ~1.8% of total cancer-related death annually. Over the past 40 years, increasing lines of evidence have supported a causal link between EBV infection and a subgroup of lung cancers (LCs). In this article, we review the current understanding of the EBV-LC association and the etiological role of EBV in lung carcinogenesis. We also discuss the clinical impact of the knowledge gained from previous research, challenges, and future directions in this field. Given the high clinical relevance of EBV-LC association, there is an urgent need for further investigation on this topic.

Pulmonary Lymphoepithelioma-Like Carcinoma Treated with Immunotherapy or Chemotherapy: A Single Institute Experience

Background

Lymphoepithelioma-like carcinoma (LELC) is a rare malignant tumor of the lung. It is related to EB virus infection. Epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) are rarely found in this disease, while high level programmed cell death ligand 1 (PD-L1) expression is observed. Here a series of patients with advanced LELC treated with immunotherapy were summarized.

Methods

This retrospective, observational study was conducted in patients who were pathologically confirmed, metastatic or recurrent LELC patients. Patients were prescribed with either chemotherapy or immunotherapy, according to treating physicians’ discretion.

Results

A total of 27 patients were included in our study, 10 with immunotherapy (ICI group) and 17 with chemotherapy (Chemo group). The objective response rates (ORR) of the two groups were 80.0% and 70.5% (p=0.678), and disease control rates (DCR) were 100% and 88.2% (p=0.516). However, the response depth was better in the ICI group. Although the cohort of patients in the ICI group was in a disadvantageous state (both up-front and salvage), the progression-free survival (PFS) was much longer (15.0 and 7.9 m, p=0.005). The 1-year PFS rate in the ICI group was also much higher (40% and 5.9%, p=0.047).

Conclusion

This study implicated the high efficiency of ICI therapy in this disease.

Pulmonary Lymphoepithelioma-Like Carcinoma: A Mini-Review

Pulmonary lymphoepithelioma-like carcinoma (PLELC) is a rare and distinct subtype of non-small-cell lung carcinoma associated with Epstein–Barr virus (EBV) infection. We systematically reviewed the recent research that expands our knowledge about PLELC, with main focus on its genetic profile, tumor-infiltrating environment, PD-L1 expression, circulating EBV-DNA, clinical utility of 18F-FDG PET/CT, and treatment strategy. A low frequency of typical driver mutations and widespread existence of copy number variations was detected in PLELC. Persistent EBV infection may trigger intense infiltration of lymphocytes, representing enhanced tumor immunity and possibly resulting in a better prognosis. Circulating EBV-DNA in the plasma of patients with PLELC may predict disease progression and response to therapy. PLELC is 18F-FDG avid, and 18F-FDG PET may help refine palliation strategies and subsequently improve the prognosis. Most of the reported patients present at early and resectable stage, and surgical resection with curative intent is the preferred approach. There is currently no consensus on the regimen of chemotherapy for patients with advanced stages. EGFR-targeted therapies seem to have no therapeutic effect, and the clinical impact of PD-1/PD-L1 therapy is uncertain but worthy of further research.

Role of cAMP and cGMP Signaling in Brown Fat

Cold-induced activation of brown adipose tissue (BAT) is mediated by norepinephrine and adenosine that are released during sympathetic nerve activation. Both signaling molecules induce an increase in intracellular levels of 3',5'-cyclic adenosine monophosphate (cAMP) in murine and human BAT. In brown adipocytes, cAMP plays a central role, because it activates lipolysis, glucose uptake, and thermogenesis. Another well-studied intracellular second messenger is 3',5'-cyclic guanosine monophosphate (cGMP), which closely resembles cAMP. Several studies have shown that intact cGMP signaling is essential for normal adipogenic differentiation and BAT-mediated thermogenesis in mice. This chapter highlights recent observations, demonstrating the physiological significance of cyclic nucleotide signaling in BAT as well as their potential to induce browning of white adipose tissue (WAT) in mice and humans.

Adult-Onset Hypothyroidism Alters the Metaplastic Properties of Dentate Granule Cells by Decreasing Akt Phosphorylation

The expression of homosynaptic long-term depression (LTD) governs the subsequent induction of long-term potentiation (LTP) at hippocampal synapses. This process, called metaplasticity, is associated with a transient increase in the levels of several kinases, such as extracellular signal-regulated protein kinases 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and Akt kinase. It has been increasingly realized that the chemical changes in the hippocampus caused by hypothyroidism may be the key underlying causes of the learning deficits, memory loss, and impaired LTP associated with this disease. However, the functional role of thyroid hormones in the "plasticity of synaptic plasticity" has only begun to be elucidated. To address this issue, we sought to determine whether the administration of 6-n-propyl-2-thiouracil (PTU) alters the relationship between priming and the induction of subsequent LTP and related signaling molecules. The activation of ERK1/2, JNK, and Akt was measured in the hippocampus at least 95 min after priming onset. We found that priming stimulation at 5 Hz for 3 s negatively impacted the induction of LTP by subsequent tetanic stimulation in hypothyroid animals, as manifested by a more rapid decrease in the fEPSP slope and population spike amplitude. This phenomenon was accompanied by lower levels of phosphorylated Akt in the surgically removed hippocampus of the hypothyroid rats compared to the euthyroid rats. The metaplastic response and the expression of these proteins in the 1-Hz-primed hippocampus were not different between the two groups. These observations suggest that decreased PI3K/Akt signaling may be involved in the compromised metaplastic regulation of LTP observed in hypothyroidism, which may account for the learning difficulties/cognitive impairments associated with this condition.

Inflammatory Stroma of Lymphoepithelioma-like Carcinoma of the Cervix: Immunohistochemical Study of 3 Cases and Review of the Literature

The aim of this study was to characterize the inflammatory infiltrate of the lymphoepithelioma-like carcinoma, a variant of squamous cell carcinoma clinically associated with a good prognosis. Immunohistochemistry was used to characterize 3 cases of lymphoepithelioma-like carcinoma in the uterine cervix, diagnosed over a period of 3 yr. The patients were between 30 and 50 yr old. Their cervical smears had shown atypical squamous cells of unknown significance or high-grade squamous intraepithelial lesions, and the initial cervical biopsy showed high-grade cervical intraepithelial neoplasia (CIN3) or squamous cell carcinoma. All patients underwent a Wertheim operation, 2 of which were preceded by a cervicectomy. Microscopically, all tumors were characterized by poorly defined sheets of undifferentiated squamous cells with a syncytial pattern and a dense background of infiltrating lymphocytes. Immunohistochemical analysis revealed that the lymphocytes were predominantly CD3 and CD8 T cells. The tumor lobules contained isolated CD8 T cells, whereas CD4 T cells and CD20 B cells surrounded the tumor lobules. CD56 NK cells and CD79 B cells were scattered in the tumor tissue. An in situ hybridization staining for Epstein-Barr encoding region was negative but all cases were immunohistochemically positive for P16. Follow-up varied between 2 mo and 2.7 yr. All 3 patients were disease free. Lymphoepithelioma-like carcinoma of the uterine cervix is a variant of squamous cell carcinoma, known for its better prognosis. The good prognosis of this tumor is potentially explained by the high levels of infiltrating CD8 T cells.

An integrated automated multispectral imaging technique that simultaneously detects and quantitates viral RNA and immune cell protein markers in fixed sections from Epstein-Barr virus-related tumours

BACKGROUND/AIM

Epstein-Barr virus (EBV) is an oncovirus that is commonly associated with the development of lymphomas and epithelial carcinomas. In the era of immunotherapy, histological evaluation of EBV-related cancers is currently a multi-sample, multi-technique process requiring separate time-consuming detection of EBV-encoded small RNAs by in situ hybridisation (ISH), and parallel labelling of sections for cancer-associated protein markers.

METHODS

Using EBV-associated tumours as proof-of-concept for feasibility, here we developed an approach that allows simultaneous detection of EBV RNAs and multiple protein markers such as PD-L1, EBV-LMP, CD8, CD4, CD20, CD30 and CD15on a single tissue section based on our recently reported automated staining protocol.

RESULTS

We successfully combined multiplex immunofluorescence (mIF) to detect 3 abovementioned protein markers involved in cancer, with ISH, and applied the protocol to f tissue samples from patients diagnosed with EBV-associated pulmonary lymphoepithelioma-like carcinoma (LELC), gastric carcinoma and Hodgkin's Lymphoma. Empowered by the Vectra 3 Automated Quantitative Pathology Imaging System, we demonstrate the utility and potential of this integrated approach to concurrently detect and quantitate viral RNA and protein biomarkers of immune and tumour cells.

CONCLUSION

This study represents an important step forward in the research and diagnosis of EBV-associated cancers, and could be readily modified to include other proteins and RNA markers to apply to other malignancies. More importantly, the novel automated ISH-mIF protocol that we detailly described here could also be readily reproduced by most of the diagnostic and research lab to future projects that aim to look at both RNA and protein markers.

Primary pulmonary lymphoepithelioma-like carcinoma initially diagnosed as squamous metaplasia: A case report and literature review

A mass was detected in the middle lobe of the right lung of a 58-year-old female. The patient did not present any symptoms and was a nonsmoker. Diagnostic evaluation revealed squamous metaplasia in the middle lobe of the right lung. During surgery, a tumor was identified, which was diagnosed as a lymphoepithelioma-like carcinoma (LELC). LELCs have been mainly reported in the Asian population and are associated with the Epstein-Barr virus (EBVs), while they are not associated with smoking. Squamous metaplasia, which is the basis of squamous cell carcinoma, differs from LELC in the therapeutic methods used and the prognostic evaluation. Squamous metaplasia requires regular follow-up in out-patient clinics, while pulmonary LELC is treated by surgery and chemotherapy. Therefore, distinguishing between LELCs and other nonmalignant or premalignant conditions is essential.

Epstein-Barr virus-associated adenocarcinomas and squamous-cell lung carcinomas

The association of Epstein-Barr virus with pulmonary neoplasms has been restricted to lymphoepithelioma-like carcinomas in Asian patients. We have selected 19 pulmonary adenocarcinomas and squamous-cell carcinomas from 1545 pulmonary neoplasms diagnosed from 1996 to 2007 in an occidental population. All of them showed a low-power appearance confusing between an epithelial and a lymphoid neoplasm, with a dense lymphocytic infiltrate intermingled with neoplastic cells giving an image akin to lymphoepithelial complexes. Five carcinomas presented typical features of Lymphoepithelioma-like lung carcinomas; but six cases could be classified as squamous-cell carcinomas and eight as adenocarcinomas. A semiquantitative polymerase chain reaction method, Early RNA genes 1 and 2 in situ hybridization as well as Latent membrane protein immunostaining for Epstein-Barr virus DNA, RNA and protein detection methods were used in every case. None of Lymphoepithelioma-like carcinomas showed positivity for Epstein-Barr virus in any used method. Otherwise four squamous-cell carcinomas and eight adenocarcinomas (12 cases) demonstrated viral sequences in polymerase chain reaction and/or in situ hybridization analysis in neoplastic cells. Moreover two adenocarcinomas also displayed human herpesvirus 6 DNA sequences coamplification in molecular analysis. Protein immunostaining was focally positive in only three cases. We performed the same analysis in 70 more cases of conventional pulmonary squamous-cell carcinomas and adenocarcinomas that gave negative results. In conclusion, a subset of pulmonary squamous-cell carcinomas and adenocarcinomas show Epstein-Barr DNA and/or RNA sequences in neoplastic cells. This finding expands the spectra of epithelial cell common tumours Epstein-Barr virus associated.

Lymphoepithelioma-like carcinoma of the lung

Lymphoepithelioma-like carcinoma (LELC) of the lung was first reported in 1987. In the past two decades, there have been just more than 150 cases reported in the literature. This uncommon but distinct form of non-small cell lung carcinoma has a predilection for young non-smoking Asians, without gender distinction. Histologically, it is indistinguishable from undifferentiated nasopharyngeal carcinoma. The carcinogenic role of latent Epstein-Barr virus infection in causing LELC of the lung has been evident almost exclusively in Asians compared with Caucasians. Among the reported cases, more than half were in early resectable stages (I or II) and there was a tendency for peribronchovascular spread with vascular encasement in advanced diseases. In order to establish the diagnosis of LELC of the lung, both nasopharyngeal carcinoma and lymphoma have to be excluded by endoscopic biopsy (with or without magnetic resonance imaging of the nasopharynx) and immunohistochemical staining of the biopsy samples. The mainstay of treatment for early-stage disease is curative surgical resection, whereas multimodality treatment (surgery, chemotherapy, radiotherapy) has been adopted in advanced or metastatic diseases. The overall survival is more favourable in LELC of the lung compared with non-LELC type of non-small cell lung carcinoma. Future collaborative studies especially on optimizing treatment for this uncommon malignancy are clearly warranted.

Highly anaplastic extraventricular ependymoma arising in an adult, mimicking metastatic adenocarcinoma with heavy stromal inflammation and emperiporesis

We report a case of extraventricular ependymoma arising in a 50-year-old woman that took an aggressive clinical course with recurrence three times. The initial tumor was a well-circumscribed nodule in the right temporal white matter measuring 2 cm in diameter. It showed variegated histological findings mimicking metastatic adenocarcinoma: an epithelioid arrangement of highly pleomorphic cells with pseudopapillary structures and perivascular pseudorosettes, and bizarre multinucleated giant cells with occasional emperiporesis surrounded by abundant mononuclear inflammatory cells, as well as a focal small area of conventional ependymoma. Emperiporesis and abundant mononuclear cell infiltration were not previously described in an ependymoma. The recurrent tumors predominantly showed an epithelioid pattern with frequent formation of astroblastoma-like pseudopapillary structures. Neoplastic cells were markedly atypical and had characteristic intracytoplasmic eosinophilic inclusion bodies. Much of the cells in both the initial and recurrent tumors showed a positive immunostaining for glial fibrillary acidic protein (GFAP) with accentuation to the cytoplasmic processes of the pseudorosettes and pseudopapillary structures. Epithelial membrane antigen (EMA) highlighted the epithelial differentiation of the tumor cells, while cytokeratin was completely negative. Although this tumor might be classified to at least WHO grade III from the histology and aggressive behavior, the exact grading is still controversial because of the rarity of such cases.

Lymphoepithelioma-like carcinoma of the uterine cervix

CONTEXT

It has been proposed that Epstein-Barr virus (EBV) plays a role in the etiology of lymphoepithelioma-like carcinoma (LELC) in diverse anatomic locations. In contrast to Asian women, Western women have a low prevalence of LELC of the uterine cervix, and EBV genomes have not been identified.

OBJECTIVE

To assess the presence of EBV in LELC of the uterine cervix in 4 white Western women.

DESIGN

We collected 4 cases of LELC of the uterine cervix between 1990 and 2000. We performed histologic and immunohistochemical analyses of formalin-fixed, paraffin-embedded tumor samples. We amplified tumor DNA with polymerase chain reaction to detect EBV, human papillomavirus, and simian virus 40 DNAs.

RESULTS

Immunohistochemically, tumor cells were positive for cytokeratins and showed strong expression of p53 and MIB-1. Staining for the oncoprotein c-Erb-B2 was focally positive, and staining for Bcl-2 and progesterone receptors was negative. Only one case showed focal nuclear staining for estrogen receptors. All cases had a dense infiltrate of mature lymphocytes expressing T-cell antigens CD45RO, CD3, and CD8. Polymerase chain reaction analysis did not detect EBV, human papillomavirus, or simian virus 40 DNA sequences in any of the 4 cases. One case had positive serologic results for anti-EBV antibodies, indicating a mild or chronic infection.

CONCLUSIONS

LELC of the uterine cervix shows the immunohistochemical profile of an aggressive tumor in spite of its good prognosis, in which CD8 cytotoxic suppressor lymphocytes could play an important role. Based on our results, the role of EBV, human papillomavirus, or simian virus 40 in the pathogenesis of LELC of the uterine cervix in Western women remains unclear.

Relationship between Epstein-Barr virus and lymphoepithelioma-like carcinoma of the lung: a clinicopathologic study of 6 cases and review of the literature

Lymphoepithelioma-like carcinoma (LELC) is a rare form of lung cancer, usually encountered in Chinese patients. Similar to nasopharyngeal carcinoma, LELC of the lung is strongly associated with Epstein-Barr virus (EBV) infection in Asian patients, but there is controversy over whether an association exists in patients from Western countries. To determine whether such a relationship exists, we retrospectively studied 6 cases of primary LELC of the lung, all of which were in Western patients. There were 4 men and 2 women, ranging in age from 49 to 75 years. The tumors ranged from 1 to 4.5 cm in diameter. Four patients had stage I disease, 1 had stage IIb disease, and 1 had stage IIIa disease. All patients are alive without evidence of disease with a follow-up of 18 to 30 months. Formalin-fixed, paraffin-embedded tissue was stained with hematoxylin-eosin for routine evaluation and immunostained for keratin and leukocyte common antigen (LCA). LCA staining was performed to exclude large-cell lymphoma. Immunoperoxidase staining (1:500 clone CS1-4; Dako, Carpinteria, CA) and in situ hybridization were performed to detect EBV. Tumors consisted of solid nests of undifferentiated tumor cells in a syncytial arrangement surrounded by heavy lymphoplasmacytic infiltrate. Tumor cells stained positively for keratin but negative for LCA. All 6 cases were negative for EBV, suggesting no association between EBV and LELC in the Western population.

Lymphoepithelioma-like carcinoma of the lung with a better prognosis. A clinicopathologic study of 32 cases

The purpose of our study was to clarify the prognosis of lymphoepithelioma-like carcinoma (LELC) of the lung, which is rare. We analyzed the clinicopathologic features of 32 cases of pulmonary LELC and compared the cases with 84 cases of pulmonary non-LELC with available long-term follow-up information. The results show that LELC of the lung as a distinct entity has a better prognosis than non-LELC. We found a significant difference in the survival rates between patients with LELC and patients with non-LELC in stage II and stages III and IV, respectively. Tumor recurrence and necrosis (5% or more of tumor) are associated with a poor prognosis. It seems that the histologic typing (Regaud type and Schmincke type) of pulmonary LELC is of no clinical value.