David Y. Mason

bcl-2 Protein in Non-Small-Cell Lung Carcinoma

BACKGROUND The proto-oncogene bcl-2 encodes a protein that inhibits programmed cell death (apoptosis). The protein is expressed in basal cells in normal human epithelium, but no data are available on the frequency or clinical importance of its expression in carcinoma. We studied bcl-2 expression in patients with non-small-cell lung carcinoma and correlated this phenomenon with survival. METHODS Immunochemical analysis with a monoclonal antibody specific for bcl-2 was used to detect the protein in tumor samples from 122 patients undergoing surgery for squamous-cell carcinoma (80 patients) or adenocarcinoma (42 patients). The possibility that bcl-2 expression correlated with survival was investigated with use of the log-rank test, hazard ratios, and their confidence intervals. RESULTS We detected bcl-2 protein in 25 percent of squamous-cell carcinomas (20 of 80) and 12 percent of adenocarcinomas (5 of 42). In adjacent normal respiratory epithelium, bcl-2 was expressed only in basal cells. Survival at five years was higher among patients with bcl-2-positive tumors, both in the group as a whole (P < 0.1) and in the group with squamous-cell carcinoma (P < 0.02). Patients 60 years of age or older who had bcl-2-positive tumors had the best prognoses, both in the group as a whole (P < 0.02) and in the group with squamous-cell carcinoma (P < 0.01). CONCLUSIONS The proto-oncogene bcl-2 is abnormally expressed in some lung carcinomas, and its expression may have prognostic importance.

Tumours of histiocytes and accessory dendritic cells: An immunohistochemical approach to classification from the International Lymphoma Study Group based on 61 cases

Tumours of histiocytes and accessory dendritic cells: an immunohistochemical approach to classification from the International Lymphoma Study Group based on 61 cases

Transferrin receptors in human tissues: their distribution and possible clinical relevance.

The distribution of transferrin receptors (TR) has been studied in a range of normal and malignant tissues using four monoclonal antibodies, BK19.9, B3/25, T56/14 and T58/1. In normal tissues TR was found in a limited number of sites, notably basal epidermis, the endocrine pancreas, hepatocytes, Kupffer cells, testis and pituitary. This restricted pattern of distribution may be relevant to the characteristic pattern of iron deposition in primary haemachromatosis. In contrast to this limited pattern of expression in normal tissue, the receptor was widely distributed in carcinomas, sarcomas and in samples from cases of Hodgkins disease. This malignancy-associated expression of the receptor may play a role in the anaemia of advanced malignancy by competing with the bone marrow for serum iron.

Diagnosis of Human Lymphoma with Monoclonal Antileukocyte Antibodies

Two monoclonal antibodies have been produced that react with antigens present on human white cells. These reagents differ from other monoclonal antibodies of similar specificity in that the antigens they recognize are resistant to conventional tissue-fixation and embedding procedures. These reagents can therefore be used in immunocytochemical staining of paraffin-embedded tissue sections. We assessed the practical usefulness of this technique in the histopathological diagnosis of human lymphoid neoplasms by staining a wide range of routine surgical biopsy specimens of normal and neoplastic tissue (gathered from five institutions), using an indirect immunoperoxidase technique. In all 40 cases of non-Hodgkins lymphoma, positive labeling of neoplastic cells was obtained with one or both antibodies. In contrast, no staining of neoplastic cells was observed in 60 samples of nonlymphoid neoplasms. We conclude that many of the difficulties encountered by histopathologists in distinguishing between lymphoid and nonlymphoid neoplasms may be overcome by immunohistologic labeling with monoclonal antibodies such as the ones we have studied.

Immunohistological Analysis of Human Lymphoma: Correlation of Histological and Immunological Categories

Publisher Summary The analysis of human tissue lymphoma biopsies by immunohistological techniques provides the opportunity for investigating whether previously established histological categories can be correlated with different patterns of antigen expression. The results reported in the chapter are gratifying in the context that many previously recognized lymphoma categories do indeed appear to represent immunologically distinct entities. In particular the concept, central to the Kiel classification, that many non-Hodgkins lymphomas, both diffuse and follicular, are derived from germinal center cells is confirmed in this study. Immunohistological analysis has also shed new light on the diffuse lymphomas. No clear-cut distinction can be drawn at present between the two major large cell categories found in the Kiel classification—centroblastic and immunoblastic. The nature of lymphomas expressing Ki-1 antigen and their relationship to Hodgkins disease requires to be elucidated. The results reported through this chapter indicate that while providing much new insight into human lymphoma, immunohistological studies also raise many new and fascinating questions.

Production of a monoclonal antibody reactive with human dendritic reticulum cells and its use in the immunohistological analysis of lymphoid tissue.

A murine monoclonal antibody (designated R4/23) which reacts strongly with human dendritic reticulum cells (DRC) is described. Immunoperoxidase staining of tissue cryostat sections revealed that this antibody reacts strongly with DRC in lymphoid follicles (both primary and secondary), and also weakly with marginal zone splenic B cells and with some peripheral follicular mantle B lymphocytes in lymph node cortical follicles. The value of antibody R4/23 is that it allows the distribution of DRC in reactive and neoplastic lymphoid tissue to be clearly delineated. Of particular interest is the fact that all cases of follicular lymphoma of germinal centre cell origin are consistently accompanied by a proliferation of DRC, even when the neoplasm is present in non-lymphoid tissue--for example, in the kidney. In contrast, DRC in B cell lymphomas of non-germinal centre origin are partially or totally obliterated.

Expression of the ALK Tyrosine Kinase Gene in Neuroblastoma

ALK (anaplastic lymphoma kinase) is a tyrosine kinase receptor, expressed as part of the chimeric NPM-ALK protein, in anaplastic large cell lymphomas (ALCLs) exhibiting the t(2;5)(p23;q35) translocation. As a result of this translocation, the NPM (nucleophosmin) gene is fused to the portion of the ALK gene encoding its intracytoplasmic segment. In normal mouse tissues, mRNA encoding the Alk receptor has been found only in neural cells, suggesting involvement of this receptor in the development of the nervous system. The purpose of the present study was to examine the presence of ALK transcripts and protein in normal human tissues and a variety of cell lines and human tumors. Emphasis was placed on neuroblastomas because other tyrosine kinase receptors are expressed in human neuroblastomas. Fifty-six cell lines, including 29 lines of neural origin, and lymphoid and nonlymphoid tissue specimens, including 24 neuroblastomas, were investigated for ALK expression, using reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemistry. The results confirmed that mRNA encoding ALK protein was not detectable in any normal or neoplastic hematopoietic tissue tested, except for t(2;5)-positive ALCL. The salient finding was that 13 of the 29 cell lines of neural origin and 22 of 24 neuroblastomas were found to express ALK transcripts and ALK protein. However, no correlation was evident between any known prognostic factors and the level of ALK expression.

Use of monoclonal antibodies for the histopathological diagnosis of human malignancy

This paper describes the use of a panel of seven monoclonal antibodies (selected so as to include reagents reactive with both epithelial and lymphoid cells) for distinguishing between anaplastic carcinoma and high grade lymphoma. Details are given of the immunohistological reactions of these antibodies against a wide range of both normal and malignant tissues and of a number of practical instances in which use of the antibody panel enabled a diagnosis to be made when routine histological examination had been inconclusive.

Novel markers of normal and neoplastic human plasmacytoid dendritic cells.

Plasmacytoid dendritic cells (pDCs) are involved in innate immunity (eg, by secreting interferons) and also give rise to CD4+CD56+ hematodermic neoplasms. We report extensive characterization of human pDCs in routine tissue samples, documenting the expression of 19 immunohistologic markers, including signaling molecules (eg, BLNK), transcription factors (eg, ICSBP/IRF8 and PU.1), and Toll-like receptors (TLR7, TLR9). Many of these molecules are expressed in other cell types (principally B cells), but the adaptor protein CD2AP was essentially restricted to pDCs, and is therefore a novel immunohistologic marker for use in tissue biopsies. We found little evidence for activation-associated morphologic or phenotypic changes in conditions where pDCs are greatly increased (eg, Kikuchi disease). Most of the molecules were retained in the majority of pDC neoplasms, and 3 (BCL11A, CD2AP, and ICSBP/IRF8) were also commonly negative in leukemia cutis (acute myeloid leukemia in the skin), a tumor that may mimic pDC neoplasia. In summary, we have documented a range of molecules (notably those associated with B cells) expressed by pDCs in tissues and peripheral blood (where pDCs were detectable in cytospins at a frequency of <1% of mononuclear cells) and also defined potential new markers (in particular CD2AP) for the diagnosis of pDC tumors.

Functional characterization of HLA-F and binding of HLA-F tetramers to ILT2 and ILT4 receptors.

HLA‐F is a human non‐classical MHC molecule. Recombinant HLA‐F heavy chain was refolded with β2‐microglobulin to form a stable complex. This complex was used as an immunogen to produce a highly specific, high‐affinity monoclonal antibody (FG1) that was used to study directly the cellular biology and tissue distribution of HLA‐F. HLA‐F has a restricted pattern of tissue expression in tonsil, spleen, and thymus. HLA‐F could be immunoprecipitated from B cell lines and from HUT‐78, a T cell line. HLA‐F binds TAP, but unlike the classical human class I molecules, was undetected at the cell surface. HLA‐F tetramers stain peripheral blood monocytes and B cells. HLA‐F tetramer binding could be conferred on non‐binding cells by transfection with the inhibitory receptors ILT2 and ILT4. Surface plasmon resonance studies demonstrated a direct molecular interaction of HLA‐F with ILT2 and ILT4. These results, together with structural predictions based on the sequence of HLA‐F, suggest that HLA‐F may be a peptide binding molecule and may reach the cell surface under favorable conditions, which may include the presence of specific peptide or peptides. At the cell surface it would be capable of interacting with LIR1 (ILT2) and LIR2 (ILT4) receptors and so altering the activation threshold of immune effector cells.