The Epstein–Barr virus (EBV), formally called Human gammaherpesvirus 4, is one of the nine known human herpesvirus types in the herpes family, and is one of the most common viruses in humans. EBV is a double-stranded DNA virus.
Adenocarcinoma is a type of cancerous tumor that can occur in several parts of the body. It is defined as neoplasia of epithelial tissue that has glandular origin, glandular characteristics, or both. Adenocarcinomas are part of the larger grouping of carcinomas, but are also sometimes called by more precise terms omitting the word, where these exist. Thus invasive ductal carcinoma, the most common form of breast cancer, is adenocarcinoma but does not use the term in its name—however, esophageal adenocarcinoma does to distinguish it from the other common type of esophageal cancer, esophageal squamous cell carcinoma. Several of the most common forms of cancer are adenocarcinomas, and the various sorts of adenocarcinoma vary greatly in all their aspects, so that few useful generalizations can be made about them.
Carcinoma is a malignancy that develops from epithelial cells. Specifically, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that arises from cells originating in the endodermal, mesodermal or ectodermal germ layer during embryogenesis.
Lymphoepithelioma is a type of poorly differentiated nasopharyngeal carcinoma characterized by prominent infiltration of lymphocytes in the area involved by tumor. Lymphoepithelioma is also known as "class III nasopharyngeal carcinoma" in the WHO classification system. It has a high tendency to metastasize and is responsive to radiotherapy. Most cases are associated with Epstein–Barr virus infection.
Nasopharyngeal carcinoma (NPC), or nasopharynx cancer, is the most common cancer originating in the nasopharynx, most commonly in the postero-lateral nasopharynx or pharyngeal recess, accounting for 50% of cases. NPC occurs in children and adults. NPC differs significantly from other cancers of the head and neck in its occurrence, causes, clinical behavior, and treatment. It is vastly more common in certain regions of East Asia and Africa than elsewhere, with viral, dietary and genetic factors implicated in its causation. It is most common in males. It is a squamous cell carcinoma of an undifferentiated type. Squamous epithelial cells are a flat type of cell found in the skin and the membranes that line some body cavities. Undifferentiated cells are cells that do not have their mature features or functions.
Medullary breast carcinoma is a rare type of breast cancer that is characterized as a relatively circumscribed tumor with pushing, rather than infiltrating, margins. It is histologically characterized as poorly differentiated cells with abundant cytoplasm and pleomorphic high grade vesicular nuclei. It involves lymphocytic infiltration in and around the tumor and can appear to be brown in appearance with necrosis and hemorrhage. Prognosis is measured through staging but can often be treated successfully and has a better prognosis than other infiltrating breast carcinomas.
Large-cell lung carcinoma (LCLC), or large-cell carcinoma (LCC) in short, is a heterogeneous group of undifferentiated malignant neoplasms that lack the cytologic and architectural features of small cell carcinoma and glandular or squamous differentiation. LCC is categorized as a type of NSCLC which originates from epithelial cells of the lung.
As of 2021, a vaccine against Epstein–Barr virus was not yet available. The virus establishes latent infection and causes infectious mononucleosis. There is also increasingly more evidence that EBV may be a trigger of multiple sclerosis. It is a dual-tropic virus, meaning that it infects two different host cell types — in this case, both B cells and epithelial cells. One challenge is that the Epstein–Barr virus expresses very different proteins during its lytic and its latent phases. Antiviral agents act by inhibiting viral DNA replication, but as of 2016, there was little evidence that they are effective against Epstein–Barr virus, they are expensive, they risk causing resistance to antiviral agents, and can cause unpleasant side effects.
There are several forms of Epstein–Barr virus (EBV) infection. These include asymptomatic infections, the primary infection, infectious mononucleosis, and the progression of asymptomatic or primary infections to: 1) any one of various Epstein–Barr virus-associated lymphoproliferative diseases such as chronic active EBV infection, EBV+ hemophagocytic lymphohistiocytosis, Burkitt's lymphoma, and Epstein–Barr virus positive diffuse large B-cell lymphoma, not otherwise specified); 2) non-lymphoid cancers such as Epstein–Barr virus associated gastric cancer, soft tissue sarcomas, leiomyosarcoma, and nasopharyngeal cancers; and 3) Epstein–Barr virus-associated non-lymphoproliferative diseases such as some cases of the immune disorders of multiple sclerosis and systemic lupus erythematosis and the childhood disorders of Alice in Wonderland Syndrome and acute cerebellar ataxia.
Epstein–Barr nuclear antigen 1 (EBNA1) is a multifunctional, dimeric viral protein associated with Epstein–Barr virus (EBV). It is the only EBV protein found in all EBV-related malignancies. It is important in establishing and maintaining the altered state that cells take when infected with EBV. EBNA1 has a glycine–alanine repeat sequence that separates the protein into amino- and carboxy-terminal domains. This sequence also seems to stabilize the protein, preventing proteasomal breakdown, as well as impairing antigen processing and MHC class I-restricted antigen presentation. This thereby inhibits the CD8-restricted cytotoxic T cell response against virus-infected cells. EBNA1 is expressed from the Qp promoter during all latency programs. It is the only viral protein expressed in latency program I.
Metanephric adenoma (MA) is a rare, benign tumour of the kidney, that can have a microscopic appearance similar to a nephroblastoma, or a papillary renal cell carcinoma.
Large cell lung carcinoma with rhabdoid phenotype (LCLC-RP) is a rare histological form of lung cancer, currently classified as a variant of large cell lung carcinoma (LCLC). In order for a LCLC to be subclassified as the rhabdoid phenotype variant, at least 10% of the malignant tumor cells must contain distinctive structures composed of tangled intermediate filaments that displace the cell nucleus outward toward the cell membrane. The whorled eosinophilic inclusions in LCLC-RP cells give it a microscopic resemblance to malignant cells found in rhabdomyosarcoma (RMS), a rare neoplasm arising from transformed skeletal muscle. Despite their microscopic similarities, LCLC-RP is not associated with rhabdomyosarcoma.
Epithelial-myoepithelial carcinoma of the lung is a very rare histologic form of malignant epithelial neoplasm ("carcinoma") arising from lung tissue.
Mucinous cystadenocarcinoma of the lung (MCACL) is a very rare malignant mucus-producing neoplasm arising from the uncontrolled growth of transformed epithelial cells originating in lung tissue.
Sarcomatoid carcinoma of the lung is a term that encompasses five distinct histological subtypes of lung cancer, including (1) pleomorphic carcinoma, (2) spindle cell carcinoma, (3) giant cell carcinoma, (4) carcinosarcoma, or (5) pulmonary blastoma.
Giant-cell carcinoma of the lung (GCCL) is a rare histological form of large-cell lung carcinoma, a subtype of undifferentiated lung cancer, traditionally classified within the non-small-cell lung carcinomas (NSCLC).
Estimates place the worldwide risk of cancers from infectious causes at 16.1%. Viral infections are risk factors for cervical cancer, 80% of liver cancers, and 15–20% of the other cancers. This proportion varies in different regions of the world from a high of 32.7% in Sub-Saharan Africa to 3.3% in Australia and New Zealand.
Adenosquamous lung carcinoma (AdSqLC) is a biphasic malignant tumor arising from lung tissue that is composed of at least 10% by volume each of squamous cell carcinoma (SqCC) and adenocarcinoma (AdC) cells.
Salivary gland–like carcinomas of the lung generally refers a class of rare cancers that arise from the uncontrolled cell division (mitosis) of mutated cancer stem cells in lung tissue. They take their name partly from the appearance of their abnormal cells, whose structure and features closely resemble those of cancers that form in the major salivary glands of the head and neck. Carcinoma is a term for malignant neoplasms derived from cells of epithelial lineage, and/or that exhibit cytological or tissue architectural features characteristically found in epithelial cells.
George Sai Wah Tsao was a professor of the School of Biomedical Sciences of the University of Hong Kong and the Director of the Faculty Core Facility of the Faculty of Medicine, the University of Hong Kong. Tsao researches the relationship between Epstein-Barr virus and nasopharyngeal carcinoma. He also created the first immortal human ovarian surface epithelial cell line.
