Langerin is a type II transmembrane C-type lectin associated with the formation of Birbeck granules in Langerhans cells. Langerin is a highly selective marker for Langerhans cells and the lesional cells of Langerhans cell histiocytosis. Although Langerin protein expression in Langerhans cell histiocytosis has been previously documented, the specificity of Langerin expression as determined by immunohistochemistry in the context of other histiocytic disorders has not been well established. ...

Pancreatobiliary and ampulla of Vater adenocarcinomas frequently metastasize to regional lymph nodes, liver, or lung and are difficult to diagnose because they lack specific immunohistochemical markers. We studied the expression of cytokeratin 7 (CK7), cytokeratin 17 (CK17), cytokeratin 20 (CK20), CDX2, mucin 1 (MUC1), mucin 2 (MUC2), and mucin 5AC (MUC5AC) in 46 cases of pancreatic ductal carcinoma, 18 ampulla of Vater adenocarcinomas, and 24 intrahepatic cholangiocarcinomas. The ...

The distinction between seminoma and embryonal carcinoma based on morphology alone can sometimes be problematic, requiring the use of immunohistochemistry to facilitate diagnosis. D2-40 is a monoclonal antibody that reacts with an oncofetal antigen expressed by fetal germ cells and testicular germ cell tumors. The diagnostic value of D2-40 immunohistochemistry in distinguishing seminoma from embryonal carcinoma has not been determined. D2-40 immunoreactivity was evaluated in a series of ...

Merkel cell polyomavirus (MCV) is a recently discovered human virus closely related to African green monkey lymphotropic polyomavirus. MCV DNA is integrated in approximately 80% of Merkel cell carcinomas (MCC), a neuroendocrine skin cancer linked to lymphoid malignancies such as chronic lymphocytic leukemia (CLL). To assess MCV infection and its association with human diseases, we developed a monoclonal antibody that specifically recognizes endogenous and transfected MCV large T (LT) ...

OBJECTIVE: To determine the clinical and prognostic significance of chromosome 11q13 amplification in squamous cell carcinoma of the head and neck.

DESIGN: Retrospective clinical analysis.

SETTING: University and private cancer centers.

PATIENTS: Fifty-six patients with pathologically confirmed head and neck squamous cell carcinoma whose tumors had been assayed for the presence or absence of chromosome 11q13 amplification.

MEASUREMENTS: The degree of DNA amplification in each tumor was ...

Using the polymerase chain reaction (PCR), it has been recently reported that the Epstein-Barr virus (EBV) is present in the majority of Schneiderian sinonasal papillomas (SNP) of the inverted type and may play a role in the pathogenesis of these lesions. The reported prevalence rates of human papillomavirus (HPV) in different types of SNP is also controversial and in need of clarification. Twenty-eight SNP from 27 patients were histologically classified and evaluated for evidence of EBV ...

The histologic classification of pulmonary neoplasms can have important implications regarding appropriate management of patients. Although the histologic classification of lung tumors is predominantly based on morphology, ancillary studies such as immunohistochemistry can be used in difficult cases, and the diagnosis of large cell neuroendocrine carcinoma requires confirmation of neuroendocrine differentiation by immunohistochemistry or electron microscopy. We immunostained 142 lung ...

Neoplasms of histiocytes and dendritic cells are rare, and their phenotypic and biological definition is incomplete. Seeking to identify antigens detectable in paraffin-embedded sections that might allow a more complete, rational immunophenotypic classification of histiocytic/dendritic cell neoplasms, the International Lymphoma Study Group (ILSG) stained 61 tumours of suspected histiocytic/dendritic cell type with a panel of 15 antibodies including those reactive with histiocytes (CD68, ...

A 30-basepair (bp) deletion in the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) gene has been reported in nasopharyngeal carcinoma and EBV-associated malignant lymphomas. Prior studies have found the deletion in about 10% to 28% of cases of Hodgkin's disease (HD), particularly in cases with aggressive histology. We studied the prevalence of 30-bp LMP1 gene deletion in EBV-positive HD in the United States (US) (12 cases) and Brazil (26 cases) with comparison to reactive ...

We studied 61 CD20- B-cell lymphomas, including 29 cases of precursor B-cell lymphoblastic leukemia/lymphoblastic lymphoma (B-ALL/B-LBL), 25 cases of CD20- recurrent mature B-cell lymphoma after rituximab therapy, and 7 cases of CD20- diffuse large B cell lymphoma (DLBCL). We used markers specific for B lineage: CD79a, Pax-5, OCT.2, and BOB.1. All B-ALL/B-LBLs expressed Pax-5 (29/29 [100%]), 25 (93%) of 27 expressed BOB.1, 23 (79%) of 29 expressed CD79a, and 6 (22%) of 27 expressed ...

A 30-bp deletion in the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) gene has been reported in nasopharyngeal carcinoma and EBV-associated malignant lymphomas. Information on this deletion in EBV-associated gastric carcinoma (EBVaGC) is limited. The association of gastric carcinoma (GC) with EBV was examined by EBV-encoded RNA (EBER) in situ hybridization in 510 patients from Japan and 80 patients from Brazil. We studied the prevalence of 30-bp LMP1 gene deletion in EBVaGC ...

Rare cases of Merkel cell carcinoma have been encountered in lymph nodes with unknown extranodal primary, which exhibit similar morphologic and immunophenotypic features to those in primary cutaneous Merkel cell carcinomas. However, it is uncertain whether the nodal Merkel cell carcinoma is a primary tumor of the lymph node or represents a metastasis from an occult or regressed extranodal lesion. To establish an accurate diagnosis of the nodal Merkel cell carcinoma can be challenging ...

We studied 48 cases of invasive breast carcinoma for evidence of Epstein-Barr virus (EBV), which is associated with many human malignancies. In situ hybridization studies to detect the presence of EBV-encoded small nonpolyadenylated RNA (EBER)-1 were performed in paraffin sections. Immunohistochemical studies to detect EBV nuclear antigen (EBNA)-1, latent membrane protein (LMP)-1, and the transactivating immediate-early BZLF1 (ZEBRA) protein were also performed in paraffin sections. The ...

Hepatocyte monoclonal antibody (Hep) (alternatively Hep Par 1 for Hep paraffin 1) has been reported to stain normal hepatic tissue and hepatocellular carcinoma (HCC) with high specificity. We have studied the Hepatocyte expression in 96 cases of HCC and 311 cases of nonhepatic epithelial tumors. All cases of HCC were also stained with CEA-Gold 5, CD10, and alpha-fetoprotein. Hep, CEA-Gold 5, CD10, and alpha-fetoprotein immunostains were performed on formalin-fixed, paraffin-embedded ...