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MTH-68/H oncolytic viral treatment in human high-grade gliomas

Application of virus therapy to treat human neoplasms has over a three decade history. MTH-68/H, a live attenuated oncolytic viral strain of the Newcastle disease virus, is one of the viruses used in the treatment of different malignancies. Here we report on the administration of MTH-68/H to patients with glioblastoma multiforme, the most common and most aggressive neuroectodermal neoplasm with a poor prognosis, averaging six months to a year. Four cases of advanced high-grade glioma were treated with MTH-68/H after the conventional modalities of anti-neoplastic therapies had failed. This treatment resulted in survival rates of 5–9 years, with each patient still living today. Against all odds, each patient resumed a lifestyle that resembles their previous daily routines and enjoys a good quality of life. Each of these patients has regularly received MTH-68/H as their sole form of onco-therapy for a number of years now without interruption.

Review of thymic hormones in cancer diagnosis and treatment.

The thymus is an endocrine organ. A unified, physiological concept of humoral regulations of the immune response has emerged in the last three decades. The thymus is the major site of production of immunocompetent T lymphocytes from their hematopoietic stem cells. This complex process required direct cell to cell, receptor based interactions, as well as in situ paracrine information via the numerous cytokines and thymic hormones produced by the cells of thymic microenvironment. Thymic hormones induce in situ T-cell marker differentiation, expression and functions. These polypeptide hormones have also been shown by means of immunocytochemistry to localize in the reticulo-epithelial (RE) cells of the thymic cellular microenvironment. Due to the great complexity of the intrathymic maturation sequence of T lymphocytes and the diverse immunophenotypically unique subpopulations of T lymphocytes, it is quite unlikely that a single thymic humoral factor could control all of the molecular steps and cell populations involved. It is much more likely that an extremely rich and diverse, but genetically determined, milieu is present within the thymus, and that thus the control of intrathymic T lymphocyte maturation and the functional maturation of T cells involves the orchestral interaction of various thymic-specific factors and other molecules during the differentiation process. Thymosin fraction 5 and its constituent peptides influence several properties of lymphocytes including cyclic nucleotide levels, migration inhibitory factor production, T-dependent antibody production, as well as the expression of various cell surface maturation/differentiation markers. Recently, derivatives of thymic hormones, mostly of thymosins, have been detected as products of neoplastically transformed cells and employed in the early diagnosis of neoplasms. In clinical trials, thymic hormones strengthen the effects of immunomodulators in immunodeficiencies, autoimmune diseases, and neoplastic malignancies. Combined chemo-immunotherapeutical anti-cancer treatment seems to be more efficacious than chemotherapy alone, and the significant hematopoietic toxicity associated with most chemotherapeutical clinical trials can be reduced significantly by the addition of immunotherapy.

Cancer-testis antigens: promising targets for antigen directed antineoplastic immunotherapy.

During the last decade, the aberrant expression of normal testicular proteins in neoplastically transformed cells became common knowledge. Cancer-testis antigens (CTAs) represent a novel family of immunogenic proteins. The genes MAGE, BAGE, GAGE, LAGE and NY-ESO-1 code for antigens that are recognised on various neoplastically transformed cells by autologous, cytolytic CD8+ T lymphocytes. The MAGE genes were initially analysed from melanomas and turned out to have an almost exclusively neoplasm specific expression pattern. In normal adult tissues, most 23 human MAGE genes are expressed only in the testis, with expression patterns suggesting that this gene family is involved in germ cell development. The SSX (synovial sarcoma on X chromosome) gene family, located on the X chromosome, encode a family of highly homologous nuclear proteins. A number of observations confirmed that all five SSX genes were expressed in normal testis. The newly detected CTA, NY-ESO-1, is regarded as one of the most immunogenic antigens ever isolated, inducing spontaneous host immune responses in 50% of patients with NY-ESO-1-expressing neoplasms. The identification of neoplasm-associated markers recognised by cellular or humoral effectors of the immune system has opened new perspectives for antigen directed, individualised antineoplastic immunotherapy. In preparation for this new era of targeted immunotherapy, a number of neoplasm-associated antigen families have been identified as targets for CD8+, cytolytic T lymphocytes in vitro and in vivo: (1) CTAs expressed in various neoplasms and in normal testis, restricted to male germ cells; (2) melanocyte differentiation antigens; (3) point mutations of normal genes; (4) antigens overexpressed in neoplastic tissues; and (5) viral antigens. Immunotherapeutic protocols directed against the CTAs have already been initiated to analyse the induction of antigen-specific cellular and humoral immune responses in vivo.

Spontaneous regression of neoplasms: new possibilities for immunotherapy

In mammalian cells, neoplastic transformation is directly associated with the expression of oncogenes, loss or simple inactivation of the function of tumour suppressor genes and the production of certain growth factors. Genes for suppression of the development of the neoplastic cellular immunophenotype, as well as inhibitory growth factors, have regulatory functions within the normal processes of cell division and differentiation. Telomerase (a ribonucleoprotein polymerase) activation is frequently detected in various neoplasms. Telomerase activation is regarded as essential for cell immortalisation and its inhibition may result in spontaneous regression of neoplasms. This phenomenon of neoplasms occurs when the malignant tissue mass partially or completely disappears without any treatment or as a result of a therapy considered inadequate to influence systemic neoplastic growth. This definition makes it clear that the term ‘spontaneous regression’ applies to neoplasms in which the overall malignant disease is not necessarily cured and to cases where the regression may not be complete or permanent. A number of possible mechanisms of spontaneous regression are reviewed, with the understanding that no single mechanism can completely account for this phenomenon. The application of the newest immunological, molecular biological and genetic insights for more individualised and adequate antineoplastic immunotherapy (alternative biotherapy) is also discussed.

The significance of immunohistochemistry in the diagnosis and therapy of neoplasms.

This review article details the diagnostical significance of immunohistochemistry, which has developed during the last quarter of the century. Certainly, the advancement of monoclonal antibody technology has been of great significance in assuring the place of immunohistochemistry in the modern accurate microscopic diagnosis of human neoplasms, as a method of choice in histopathology. The fact still remains that in order to properly assess any immunohistochemical reactivity used for differential diagnostic purposes, the target cells have to be identified as neoplastically transformed cells by routine histopathological techniques. Selected groups of target molecules of great significance in cancer biology are discussed. The discovery of neoplasm-associated antigens has not only made the more accurate diagnosis of human cancer feasible but has also shed light on the extensive immunophenotypical heterogeneity of even the most closely linked human malignancies. The identification of disseminated neoplastically transformed cells by immunohistochemistry has allowed for a clearer picture of cancer invasion and metastasis, as well as the evolution of the tumour cell associated immunophenotype towards increased malignancy. Some possibilities of neoplasm-associated antigen targeted, receptor-directed immunotherapy are discussed and reviewed in this manuscript. Future antineoplastic therapeutical approaches should see the inclusion of a variety of immunotherapies, in the form of an individualised ‘cocktail’ specific for the particular immunophenotypical pattern associated with each individual patient’s neoplastic disease.

Thymic reticulo-epithelial cells: key cells of neuroendocrine regulation

The reticulo-epithelial (RE) cellular network of the thymic stromal cellular microenvironment plays a vital role in neuroendocrine regulation and lymphoid cell homing and development. Transmission electronmicroscopic observations have confirmed that there are four functional subtypes of medullar RE cells: undifferentiated; squamous; villous; and cystic. Immunocytochemical observations have shown that the secreted thymic hormones, thymosin α1 and thymopoietin (and its short form, thymopentin or TP5), are both produced by RE cells. Thymic RE cells also produce numerous cytokines, including IL-1 and -6, G-CSF, macrophage-CSF and GM-CSF that likely are important during the various stages of thymocyte activation and differentiation. The coexistence of pituitary hormone and neuropeptide secretion, such as growth hormone, prolactin, adrenocorticotopic hormone and thyroid-stimulating hormone, among many others, and the production of a number of interleukins and growth factors, as well as the expression of receptors for all, by the same RE cell, is an unique molecular biological phenomenon. The thymic RE cell network represents an important cellular and humoral microenvironment in the neuroendocrine homeopathic regulatory mechanisms of the multicellular organism.

Immunocytochemical detection of leukocyte-associated and apoptosis-related antigen expression in childhood brain tumors

During systematic cell-surface antigen expression profile analyses of 76 primary childhood brain tumors [34 medulloblastomas (MED)/primitive neuroectodermal tumors (PNETs) and 42 astrocytomas (ASTR)], a library of monoclonal antibodies (MoABs) directed against various leukocyte-associated, lymphocyte cell-line differentiation antigens in childhood brain tumors was utilized. The antigens were detected employing an indirect, biotin-streptavidin conjugated alkaline phosphatase (AP) immunocytochemical technique. Major histocompatibility complex (MHC) class I restricted, tumor-associated antigen (TAA) specific, CD8(+) cytotoxic T lymphocytes (CTL) were identified in 58/76 (76.32%) brain tumors, and usually represented 1-10% of all cells, but in some cases 30-44% of the cells were CD8(+). CD4(+), MHC class II restricted helper lymphocytes were present in 65/76 (85.53%) brain tumors, and accounted for 1-10% of the observed cells. Macrophages were present in 74/76 (97.37%) brain tumors, and their number also represented 1-10% of all observed cells in the brain tumor frozen sections. Leukocyte common antigen (LCA) expression was detected in all 76 (100%) brain tumors studied. MoAB UJ 308 detected the presence of premyelocytes and mature granulocytes in 60/76 (78.95%) brain tumors. Natural killer (NK) cells were not defined in the observed brain tumors. The great majority of childhood glial tumors, particularly ASTRs express Fas (APO-1/CD95) receptor whereas normal cells in the central nervous system (CNS) do not. FasR is a transmembrane glycoprotein which belongs to the nerve growth factor/tumor necrosis factor (NGF/TNF) receptor superfamily. As part of our screening, the 42 childhood ASTRs were also investigated for expression of CD95. We detected strong expression (strong intensity of staining, number of stained cells 50-100%) of FasR, employing formalin fixed, paraffin-wax embedded tissue slides. Brain tumors and melanomas have been shown to produce their autocrine FasL, and are even capable of switching CD95-related signal transduction from the PCD pathway to a proliferative pathway. In view of our results, we conclude that: (1) the tumor infiltrating leukocytes in MEDs/PNETs and ASTRs represent a very diverse population and are present in a great majority of the cases studied; (2) the strong expression of FasR in ASTRs provides a manner in which T lymphocytes may exert their anti-tumor effects, but may also represent yet another way that tumors may evade the immune response; and (3) further observations of the expression of various antigens involved in juxtacrine, in situ growth control are necessary for the refinement of cellular immunotherapeutical approaches in the treatment of human malignancies.

Immunophenotype profile of childhood medulloblastomas and supratentorial primitive neuroectodermal tumors using 16 monoclonal antibodies

Immunophenotype analysis of 17 childhood medulloblastoma (MED) and supratentorial primitive neuroectodermal tumors (SPNET) was performed on frozen sections using 16 monoclonal antibodies (MoAb) with the biotin‐streptavidin alkaline phosphatase immunohistochemical technique. Neuroectodermal associated antigens, reacting with MoAb UJ13/A, UJ127.11, UJ167.11, and UJ223.8 were detected on > 10% of the cells in 15 of 17 MED/SPNET. Thy‐1 was present on 14 of 17 tumors and absent on two of three SPNET. Neuronal (NF) and glial (GFAP) differentiation markers were evaluated. NF‐H was demonstrated in 15 of 17, NF‐M in six of 17 and NF‐L in one of 17 tumors; GFAP was positive in nine of 17 patients. in nine of 17 MED/SPNET both proteins were present within the same tumor. Common leukocyte antigen was demonstrated on > 50% of the cells in four of 14 tumors as were shared tumor/leukocyte markers using monoclonal antibodies Thy‐1, PI153/3, UJ308. The most frequent MED immunophenotype analysis was UJ 13/A+, UJ 127.11+, UJ 167.11+, UJ223.8+, PI 153/3+, A2B5+, GFAP+, NF‐H+, and CLA–, NF‐M–, NF‐L–, 215–, 275–, 282.1–. The authors conclude that MED and SPNET are heterogeneous for expression of 16 markers and have similar immunophenotype analysis profiles, supporting the concept of their common, neuroectodermal origin. Common leukocyte antigen on both tumor cells and leukocytes precludes identification of tumor infiltrating leukocytes using monostaining techniques.

Thymic hormones in cancer diagnostics and treatment

The thymus is an endocrine organ. A unified, physiological concept of humoral regulation of the immune response emerged in the last three decades. The thymus is the primary major site of production of immunocompetent T-lymphocytes from their haematopoietic stem cells. The thymus provides a superior humoral microenvironment for the development of immunocompetent T-lymphocytes. Although yolk sac derived pre-T stem cells enter the thymus using a homing receptor, the immigration process requires also secretion of a peptide, called thymotaxin by the cells of the reticulo-epithelial (RE) network. This complex process requires direct cell to cell, receptor based interactions, as well as in situ paracrine information via the numerous cytokines and thymic hormones produced by the RE cells of thymic microenvironment. Thymic hormones induce in situ T-lymphocyte marker differentiation, expression and functions. These polypeptide hormones have also been shown by means of immunocytochemistry to localise in the RE cells of the thymic cellular microenvironment. Based on the complexity of the intrathymic maturation sequence of T-lymphocytes and the increasing numbers of T-lymphocyte subpopulations that are being identified, it would be surprising if a single thymic humoral factor could control all of the molecular steps and cell populations involved. Rather, it would appear that the control of intrathymic T-lymphocyte maturation and functional maturation involves a complex number of thymic-specific factors and other molecules that rigidly control the intermediary steps in the differentiation process. Thymosin fraction 5 (TF5) and its component polypeptides influence a variety of lymphocyte properties including cyclic nucleotide levels, migration inhibitory factor production, T-dependent antibody production and expression of certain surface maturation/differentiation markers. Recently, thymic hormones, mostly thymosins have been employed not only in neoplasms’ early detection but also in clinical trials to strengthen the effects of immunomodulators in immunodeficiencies, autoimmune diseases and neoplastic malignancies. Combined chemoimmunotherapeutical antineoplastic treatment seems to be useful. Generally, haematopoietic toxicity of every chemotherapeutical clinical trial can be reduced significantly by the immunotherapy, compared to 50% in patients treated with chemotherapy alone.

Mechanisms and markers of carcinogenesis and neoplastic progression.

Neoplastic transformation evolves over a period of time involving the progression of the cellular immunophenotype (IP) from normal to hyperplastic to dysplastic, and finally, to fully malignant IPs. Superimposed on these changes is the interaction of the initiated cell with its microenvironment, whereby the neoplastically transformed cells, through the regulation or dysregulation of cytoskeletal, integrin, protease and adhesion molecules, develop a novel manner of relation with their surrounding microenvironment. Studies of the neuroendocrine-immune network revealed that the hormonal and cytokine milieu plays an important role impacting the growth and dedifferentiation capabilities of neoplastic cells. This is further affected by the tumour cells themselves determining the constitution of this hormonal microenvironment, allowing the most aggressive and invasive of neoplastically transformed cell clones to promote their own growth and dissemination. The elucidation of the steps of the progression of cancer from premalignant to metastatic and invasive forms is of utmost importance in the differential diagnosis of neoplasms and in the establishment of more efficacious therapeutic regimens. These regimens will certainly begin to take on a more individualised form. The functional characterisation of various human malignancies as to the neoplastically transformed cells’ IP, the bases of their interaction with tissue stromal elements, and the molecules involved in the humoral microenvironment of the particular stage of tumour will certainly allow for the better diagnosis, staging, prognostication and treatment of cancers in the future. This paper reviews carcinogenesis from nutritional, genetic and molecular, and humoral aspects, and discusses the importance of tumour markers in the diagnosis and therapeutic management of human cancer.