Is cancer a macrophage-mediated autoaggressive disease?

Metabolic management of microenvironment acidity in glioblastoma

Glioblastoma (GBM), similar to most cancers, is dependent on fermentation metabolism for the synthesis of biomass and energy (ATP) regardless of the cellular or genetic heterogeneity seen within the tumor. The transition from respiration to fermentation arises from the documented defects in the number, the structure, and the function of mitochondria and mitochondrial-associated membranes in GBM tissue. Glucose and glutamine are the major fermentable fuels that drive GBM growth. The major waste products of GBM cell fermentation (lactic acid, glutamic acid, and succinic acid) will acidify the microenvironment and are largely responsible for drug resistance, enhanced invasion, immunosuppression, and metastasis. Besides surgical debulking, therapies used for GBM management (radiation, chemotherapy, and steroids) enhance microenvironment acidification and, although often providing a time-limited disease control, will thus favor tumor recurrence and complications. The simultaneous restriction of glucose and glutamine, while elevating non-fermentable, anti-inflammatory ketone bodies, can help restore the pH balance of the microenvironment while, at the same time, providing a non-toxic therapeutic strategy for killing most of the neoplastic cells.

Can the Mitochondrial Metabolic Theory Explain Better the Origin and Management of Cancer than Can the Somatic Mutation Theory?

A theory that can best explain the facts of a phenomenon is more likely to advance knowledge than a theory that is less able to explain the facts. Cancer is generally considered a genetic disease based on the somatic mutation theory (SMT) where mutations in proto-oncogenes and tumor suppressor genes cause dysregulated cell growth. Evidence is reviewed showing that the mitochondrial metabolic theory (MMT) can better account for the hallmarks of cancer than can the SMT. Proliferating cancer cells cannot survive or grow without carbons and nitrogen for the synthesis of metabolites and ATP (Adenosine Triphosphate). Glucose carbons are essential for metabolite synthesis through the glycolysis and pentose phosphate pathways while glutamine nitrogen and carbons are essential for the synthesis of nitrogen-containing metabolites and ATP through the glutaminolysis pathway. Glutamine-dependent mitochondrial substrate level phosphorylation becomes essential for ATP synthesis in cancer cells that over-express the glycolytic pyruvate kinase M2 isoform (PKM2), that have deficient OxPhos, and that can grow in either hypoxia (0.1% oxygen) or in cyanide. The simultaneous targeting of glucose and glutamine, while elevating levels of non-fermentable ketone bodies, offers a simple and parsimonious therapeutic strategy for managing most cancers.

Gestational tumors as a model to probe reticulate evolution in human neoplasia

Reticulate evolution, which involves the transfer of genes and other inheritable information between organisms, is of interest to a cancer researcher if only because "pirating" a trait can help a cell and its progeny adapt, survive, or take over much faster than by accumulating random mutations. However, despite being observed repeatedly in experimental models of neoplasia, reticulate evolution is assumed to be negligible in human cancer primarily because detecting gene transfer between the cells of the same genetic background can be difficult or impossible. This commentary suggests that gestational tumors, which are genetically distinct from the women who carry them, provide an opportunity to test whether reticulate evolution affects the development of human neoplasia.

Molecular biology of brain metastasis

Metastasis to the central nervous system (CNS) remains a major cause of morbidity and mortality in patients with systemic cancer. As the length of survival in patients with systemic cancer improves, thanks to multimodality therapies, focusing on metastases to the CNS becomes of paramount importance. Unique interactions between the brain’s micro-environment, blood-brain barrier, and tumor cells are hypothesized to promote distinct molecular features in CNS metastases that may require tailored therapeutic approaches. This review will focus on the pathophysiology, epigenetics, and immunobiology of brain metastases in order to understand the metastatic cascade. Cancer cells escape the primary tumor, intravasate into blood vessels, survive the hematogenous dissemination to the CNS, arrest in brain capillaries, extravasate, proliferate, and develop angiogenic abilities to establish metastases. Molecular biology, genetics, and epigenetics are rapidly expanding, enabling us to advance our knowledge of the underlying mechanisms involved. Research approaches using cell lines that preferentially metastasize in vivo to the brain and in vitro tissue-based studies unfold new molecular leads into the disease. It is important to identify and understand the molecular pathways of the metastatic cascade in order to target the investigation and development of more effective therapies and research directions.

The problem of colliding networks and its relation to cell fusion and cancer

Cell fusion, a process that merges two or more cells into one, is required for normal development and has been explored as a tool for stem cell therapy. It has also been proposed that cell fusion causes cancer and contributes to its progression. These functions rely on a poorly understood ability of cell fusion to create new cell types. We suggest that this ability can be understood by considering cells as attractor networks whose basic property is to adopt a set of distinct, stable, self-maintaining states called attractors. According to this view, fusion of two cell types is a collision of two networks that have adopted distinct attractors. To learn how these networks reach a consensus, we model cell fusion computationally. To do so, we simulate patterns of gene activities using a formalism developed to simulate patterns of memory in neural networks. We find that the hybrid networks can assume attractors that are unrelated to parental attractors, implying that cell fusion can create new cell types by nearly instantaneously moving cells between attractors. We also show that hybrid networks are prone to assume spurious attractors, which are emergent and sporadic network states. This finding means that cell fusion can produce abnormal cell types, including cancerous types, by placing cells into normally inaccessible spurious states. Finally, we suggest that the problem of colliding networks has general significance in many processes represented by attractor networks, including biological, social, and political phenomena.

Role of the systemic immune system in brain metastasis

Metastatic disease in the central nervous system (CNS) is a cause of increasing mortality amongst cancer patients. As with other types of cancer, cells of the systemic immune system play a range of important roles in the development of metastatic lesions in the CNS, both repressing and promoting tumour growth. Recent advances in immunotherapy have changed the emphasis in cancer treatment away from conventional chemotherapy and radiotherapy for certain tumour types. Despite this, our understanding of systemic immune system involvement in CNS metastases remains poor. The blood-brain barrier prevents the majority of diagnostic and therapeutic agents from crossing into the brain parenchyma until the late stages of metastatic disease. Thus, the development of immunotherapy for CNS pathologies is particularly desirable. This review draws together our current understanding in the relationships between CNS metastases and circulating systemic immune cells. We discuss the roles that circulating systemic immune cells may play in the homing of metastatic cells to the perivascular space, and the pro-metastatic and antagonistic roles that infiltrating systemic immune cells may play at sites of metastasis. This article is part of a Special Issue entitled 'Neuroinflammation in neurodegeneration and neurodysfunction'.

On the origin of cancer metastasis

Metastasis involves the spread of cancer cells from the primary tumor to surrounding tissues and to distant organs and is the primary cause of cancer morbidity and mortality. In order to complete the metastatic cascade, cancer cells must detach from the primary tumor, intravasate into the circulatory and lymphatic systems, evade immune attack, extravasate at distant capillary beds, and invade and proliferate in distant organs. Currently, several hypotheses have been advanced to explain the origin of cancer metastasis. These involve an epithelial mesenchymal transition, an accumulation of mutations in stem cells, a macrophage facilitation process, and a macrophage origin involving either transformation or fusion hybridization with neoplastic cells. Many of the properties of metastatic cancer cells are also seen in normal macrophages. A macrophage origin of metastasis can also explain the long-standing "seed and soil" hypothesis and the absence of metastasis in plant cancers. The view of metastasis as a macrophage metabolic disease can provide novel insight for therapeutic management.

Hypothesis: are neoplastic macrophages/microglia present in glioblastoma multiforme?

Most malignant brain tumours contain various numbers of cells with characteristics of activated or dysmorphic macrophages/microglia. These cells are generally considered part of the tumour stroma and are often described as TAM (tumour-associated macrophages). These types of cells are thought to either enhance or inhibit brain tumour progression. Recent evidence indicates that neoplastic cells with macrophage characteristics are found in numerous metastatic cancers of non-CNS (central nervous system) origin. Evidence is presented here suggesting that subpopulations of cells within human gliomas, specifically GBM (glioblastoma multiforme), are neoplastic macrophages/microglia. These cells are thought to arise following mitochondrial damage in fusion hybrids between neoplastic stem cells and macrophages/microglia.

Perspectives on the mesenchymal origin of metastatic cancer

Emerging evidence suggests that many metastatic cancers arise from cells of the myeloid/macrophage lineage regardless of the primary tissue of origin. A myeloid origin of metastatic cancer stands apart from origins involving clonal evolution or epithelial-mesenchymal transitions. Evidence is reviewed demonstrating that numerous human cancers express multiple properties of macrophages including phagocytosis, fusogenicity, and gene/protein expression. It is unlikely that the macrophage properties expressed in metastatic cancers arise from sporadic random mutations in epithelial cells, but rather from damage to an already existing mesenchymal cell, e.g., a myeloid/macrophage-type cell. Such cells would naturally embody the capacity to express the multiple behaviors of metastatic cells. The view of metastasis as a myeloid/macrophage disease will impact future cancer research and anti-metastatic therapies.

Cancer as a metabolic disease

Emerging evidence indicates that impaired cellular energy metabolism is the defining characteristic of nearly all cancers regardless of cellular or tissue origin. In contrast to normal cells, which derive most of their usable energy from oxidative phosphorylation, most cancer cells become heavily dependent on substrate level phosphorylation to meet energy demands. Evidence is reviewed supporting a general hypothesis that genomic instability and essentially all hallmarks of cancer, including aerobic glycolysis (Warburg effect), can be linked to impaired mitochondrial function and energy metabolism. A view of cancer as primarily a metabolic disease will impact approaches to cancer management and prevention.

The role of macrophages in the development and progression of AIDS-related non-Hodgkin lymphoma

Despite HAART, patients infected with HIV develop NHL at a significantly higher level than the noninfected population. The primary difference between lymphoma in non-HIV-infected individuals and those with ARL is that ARL is consistently high-grade and metastatic. The emergence of ARL is associated with the presence of macrophage viral reservoirs, similar to what has been observed for HAD. HIV-infected macrophages, as seen by histology and HIV p24 staining, are present in approximately half of ARLs. Macrophage reservoirs recruit additional immune cells, including monocytes/macrophages, through the release of chemoattractants. Additionally, TAM are known to promote tumor progression for most cancer types, including lymphomas. This review will highlight and discuss the role of macrophage viral reservoirs in the development and progression of ARLs and hopefully, shed light on this new and interesting field.

Influence of methotrexate and cisplatin on tumor progression and survival in the VM mouse model of systemic metastatic cancer

We recently identified a new tumor (VM-M3), which arose spontaneously in the brain of an inbred VM mouse. When grown outside the brain, the VM-M3 tumor expresses all major biological processes of metastasis to include local invasion, intravasation, immune system survival, extravasation, and secondary tumor formation involving lung, liver, kidney, spleen and brain. The VM-M3 tumor also expresses multiple properties of macrophage-like cells similar to those described previously in numerous human metastatic cancers suggesting that the VM-M3 model will be useful for studying most types of metastatic cancer, regardless of tissue origin. VM-M3 tumor cells, expressing firefly luciferase (VM-M3/Fluc), were grown subcutaneously in the immunocompetent and syngeneic VM mouse host. The antimetastatic effects of methotrexate (MTX; 25 mg/kg) and cisplatin (10-15 mg/kg) were evaluated following i.p. injections administered once/wk for 3 weeks. Bioluminescent imaging was used to measure VM-M3/Fluc growth and metastasis. All (12/12) control mice developed systemic cancer within 21 days of subcutaneous VM-M3/Fluc implantation. Although methotrexate did not inhibit VM-M3/Fluc primary tumor growth, it reduced lung and liver metastasis by 50% and completely inhibited metastasis to kidneys, spleen and brain. Cisplatin significantly reduced primary tumor growth, blocked metastasis to lung, liver, kidneys, spleen and brain, and significantly increased survival in all treated animals. Our findings show that the response of the VM-M3/Fluc tumor to MTX and cisplatin is similar to that reported in humans with metastatic disease. These findings indicate that the VM-M3/Fluc tumor is a reliable preclinical model for evaluating antimetastatic cancer therapies and underlying control pathways.

Mechanisms of metastasis

Metastasis is an enormously complex process that remains to be a major problem in the management of cancer. The fact that cancer patients might develop metastasis after years or even decades from diagnosis of the primary tumor makes the metastatic process even more complex. Over the years many hypotheses were developed to try to explain the inefficiency of the metastatic process, but none of these theories completely explains the current biological and clinical observations. In this review we summarize some of the proposed models that were developed in attempt to understand the mechanisms of tumor dissemination and colonization as well as metastatic progression.

Metastatic cancer cells with macrophage properties: evidence from a new murine tumor model

Metastasis is the process by which cancer cells disseminate from the primary neoplasm and invade surrounding tissue and distant organs, and is the primary cause of morbidity and mortality for cancer patients. Most conventional cancer therapies are ineffective in managing tumor metastasis. This has been due in large part to the absence of in vivo metastatic models that represent the full spectrum of metastatic disease. Here we identify 3 new spontaneously arising tumors in the inbred VM mouse strain, which has a relatively high incidence of CNS tumors. Two of the tumors (VM-M2 and VM-M3) reliably expressed all of the major biological processes of metastasis to include local invasion, intravasation, immune system survival, extravasation and secondary tumor formation involving liver, kidney, spleen, lung and brain. Metastasis was assessed through visual organ inspection, histology, immunohistochemistry and bioluminescence imaging. The metastatic VM tumor cells also expressed multiple properties of macrophages including morphological appearance, surface adhesion, phagocytosis, total lipid composition (glycosphingolipids and phospholipids) and gene expression (CD11b, Iba1, F4/80, CD68, CD45 and CXCR4). The third tumor (VM-NM1) grew rapidly and expressed properties of neural stem/progenitor cells, but was neither invasive nor metastatic. Our data indicate that spontaneous brain tumors can arise from different cell types in VM mice and that metastatic cancer can represent a disease of macrophage-like cells similar to those described in several human metastatic cancers. The new VM tumor model will be useful for defining the biological processes of cancer metastasis and for evaluating potential therapies for tumor management.

Cell-to-cell fusion as a link between viruses and cancer

The ability to fuse cells is shared by many viruses, including common human pathogens and several endogenous viruses. Here we will discuss how cell fusion can link viruses to cancer, what types of cancers it can affect, how the existence of this link can be tested and how the hypotheses that we propose might affect the search for human oncogenic viruses. In particular, we will focus on the ability of cell fusion that is caused by viruses to induce chromosomal instability, a common affliction of cancer cells that has been thought to underlie the malignant properties of cancerous tumours.

Calcium-pterin suppresses mitogen-induced tryptophan degradation and neopterin production in peripheral blood mononuclear cells

Antitumor activity of a calcium-pterin suspension has been described in vitro and in animal model systems. Recent studies provide some evidence that this effect involves immune-mediated mechanisms. We investigated the influence of calcium-pterin on freshly isolated human peripheral blood mononuclear cells (PBMC) stimulated with the mitogens phytohaemagglutinin and concanavalin A in vitro. Influence of calcium-pterin on tryptophan-degrading enzyme indoleamine (2,3)-dioxygenase (IDO) and on neopterin production was monitored in supernatants of cells. Increased neopterin concentrations as well as accelerated tryptophan degradation have been found to predict poor prognosis in patients with cancer, and both these immunobiochemical pathways are induced by the pro-inflammatory cytokine interferon-gamma. Compared to unstimulated cells, mitogens induced degradation of tryptophan and formation of neopterin in PBMC, and upon addition of calcium-pterin, both biochemical results were suppressed in a dose-dependent way. Thus, calcium-pterin suppresses immunological pathways in vitro that in patients with malignant diseases characterize an unfavorable prognosis. The effect of the compound to suppress IDO activity could be of considerable relevance for the antitumoral effect of the compound because activation of the enzyme is considered as an immune-escape mechanism of tumor cells.

GnT-V, macrophage and cancer metastasis: a common link

GnT-V generated, beta1,6-branched polylactosamines are a common feature shared by normal granulocytes, monocytes, and a variety of malignant cells. Furthermore, activation of GnT-V in oncogenic transformation induces invasiveness and metastatic potential in mice as well as in humans. In view of the common expression of lymphocytic/monocytic trait, motility, and GnT-V by metastatic cancer cells, macrophage fusion hybrids were generated in vitro with Cloudman S91 mouse melanoma cells to test whether the parental traits are co-expressed in hybrids and how those are related to altered phenotypes in relation to metastasis. In fact, the fusion hybrids are highly metastatic in vivo, motile in vitro, and express macrophage-associated traits of increased GnT-V activity, beta1,6 branching, and polylactosamine content. A Spontaneously formed lung melanoma metastases have been identified and characterized as host x tumor hybrid containing higher DNA content than parental cells and increased GnT-V activity. The results, taken together, could reflect prior fusion of tumor-associated macrophages with cells of the primary tumor, and therefore establish a possible common link between elevated expression of GnT-V and malignant transformation, a well-known report. Moreover, the fusion hybrids with metastatic potential ranging from high to low offer a genetically matched model system, for identification and characterization of differentially expressed genes in association with metastasis, since the fusion partners are derived from the same species of mouse (DBA/2J).

Contradictory Concepts in the Etiology and Regression of Kaposi's Sarcoma. The Ferenc Györkey Memorial Lecture

The Introduction is an overview of 3 decades of works performed by Professor Ferenc Györkey (in many cases in collaboration with the author) and aimed at the elucidation of viral participation in the etiology of arteriosclerosis, SLE, hairy cell leukemia, HD, AIDS and KS. Controversial issues surrounding the etiology, treatment and regression of KS are discussed in terms of paracrine and autocrine loops of growth factors; protooncogene-oncogene activations, immunosuppression and retro- and/or herpesviral etiology. In regressing KS lesions the roles played by Fas, Bcl-2, Bax, TNFß; apoptotic-antiapoptotic events; and antiangiogenesis agents especially that of Hu-r-IFNa are elaborated on.

Tumour cell hybridization and metastasis revisited

This article reviews a long-standing hypothesis that metastases might be initiated through the generation of hybrids between primary tumour cells and tumour-infiltrating leucocytes such as macrophages. In this concept the hybrids become metastatic through expression of the leucocyte motility phenotype. A history of the hybrid hypothesis is presented along with recent evidence on how macrophage x tumour cell hybridization could account for some of the most defining characteristics of metastatic cells: aneuploidy, enhanced motility, aberrant glycosylation and, particularly seen in melanoma, phenotypic diversity.

Melanoma x macrophage hybrids with enhanced metastatic potential

Studies were conducted on the hypothesis that melanoma metastasis might be initiated through the generation of hybrids comprised of cells of the primary tumor and tumor-infiltrating leukocytes. Fusion hybrids were generated in vitro between weakly metastatic Cloudman S91 mouse melanoma cells and normal mouse or human macrophages. Hybrids were implanted s.c. in the tail and mice were monitored for metastases. Controls included parental S91 cells, autologous S91 x S91 hybrids, and B16F10 melanoma cells. Of 35 hybrids tested, most were more aggressive than the parental melanoma cells, producing metastases sooner and in more mice. A striking characteristic was heterogeneity amongst hybrids, with some lines producing no metastases and others producing metastases in up to 80% of mice. With few exceptions, hybrids with the highest metastatic potential also had the highest basal melanin content whereas those with the lowest metastatic potential were basally amelanotic, as were the parental melanoma cells. A spontaneous in vivo supermelanotic hybrid between an S91 tumor cell and DBA/2J host cell was one of the most metastatic lines. Hybrids with the highest metastatic potential also exhibited markedly higher chemotaxis to fibroblast-conditioned media. Histologically, the metastatic hybrids demonstrated vascular invasion and spread to distant organs similar to that of metastatic melanomas in mice and humans. Thus previous findings of enhanced metastasis in leukocyte x lymphoma hybrids can now be extended to include leukocyte x melanoma hybrids. Whether such hybridization is a natural cause of metastasis in vivo remains to be determined; however the fusion hybrids with genetically-matched parents described herein so closely resembled naturally-occurring metastatic melanoma cells that they could serve as useful new models for studies of this complex and deadly phenomenon.

Tumorigenesis and cell evolution

All kinds of hypotheses have been proposed to explain the mechanism of tumorigenesis. Up until now, we have not had any generally acknowledged model that helps us understand the process. In this paper, I propose a dynamic model of how tumor cells escape the supervision of the immune system; I also examine the possibility that tumorigenesis is a two-stage process. Finally, I suggest that our understanding of the molecular level of tumorigenesis be reappraised.

Suppression of macrophage function by suture materials and anastomotic recurrence of Crohn's disease

After surgical excision of bowel, Crohn's disease is likely to recur around the anastomosis. It is suggested that this may indicate a biological effect of suture materials on gastrointestinal immunology. To investigate this, the influence of six suture materials on the function of macrophages obtained from the rat peritoneal cavity and human intestinal mucosa was assessed. All materials significantly impaired macrophage function.

Urinary neopterin in malignant lymphoma

Urinary neopterin levels were studied in 96 patients with malignant lymphomas. Twenty-eight had Hodgkin's disease and 68 non-Hodgkin's lymphoma. Neopterin excretion was significantly related to the clinical stage of the disease. Mean neopterin excretion in patients with active disease (634 +/- 527 mumol neopterin/mol creatinine) was significantly higher (p = 0.000) than in patients in complete remission (198 +/- 105 mumol neopterin/mol creatinine). Mean neopterin levels of patients in stage III-IV were higher than for patients in stage I-II. These findings were the same in patients with Hodgkin's disease and those with non-Hodgkin's lymphoma (659 +/- 593-425 +/- 316 mumol neopterin/mol creatinine), regardless of the histological subtype. A significant correlation was found between neopterin excretion, ESR (r = 0.31; p = 0.003) and hemoglobin (r = -0.40; p = 0.000). Longitudinal analysis showed a trend towards a correlation between response to therapy and neopterin excretion. These findings suggest that neopterin may be a useful prognostic marker in non-Hodgkin's lymphoma.

Tumor hypoxia, reoxygenation and oxygenation strategies: possible role in photodynamic therapy

The concept of hypoxia and its role in tumor therapy are currently under re-evaluation. Poor oxygenation is no longer visualized as an independent feature promoting necrosis and resistance to treatments, but rather as one of the several interdependent microenvironmental parameters associated with impaired blood perfusion. Tumor cells display several survival strategies and remain clonogenic for long periods in nutrient-deprived situations. Reoxygenation may cause lethal damage, improve the response to therapy, or else allow the cell variants adapted to hypoxia to resume proliferation with enhanced aggressiveness and resistance to treatment. The blood supply parameters, oxygenation status and metabolism of malignant cells are discussed here from the standpoint of tumor photodynamic therapy. The role of the tumor interstitial fluid as oxygen- and sensitizer-carrier is discussed. Techniques for assessing tumor oxygenation and for mapping hypoxic territories are described. Strategies for locally improving the oxygenation levels or for selectively destroying the hypoxic populations are outlined.

Immunolocation of TNF-alpha/cachectin in human melanoma cells: studies on co-cultivated malignant melanoma

We have investigated the ability of metastatic cells to produce the macrophage cytokine, TNF-alpha/cachectin, as these cells have macrophage-like properties such as infiltration and migration. We looked for TNF-alpha/cachectin in three tumor cell lines derived from human malignant melanomas and six co-cultivated malignant melanomas derived, in vitro, from these three cell lines plus angioma fibroblasts. Immunohistochemistry with an anti-TNF-alpha/cachectin monoclonal antibody showed that TNF-alpha/cachectin was produced by two of the three parent melanoma cell lines. All the tumor cells in both the co-cultivated malignant melanomas and their in vitro tumorous nodules produced TNF-alpha/cachectin, even those derived from the melanoma cell line, which originally did not. The results clearly show that TNF-alpha/cachectin can be produced by non-hematopoietic tumor cells. A co-cultivated tumor model prepared from other types of human tumor cell lines promises to provide a useful tool for exploring the relationship between TNF-alpha/cachectin and oncogenesis.

Spontaneous fusion between splenocytes and myeloma cells induced by bacterial immunization

Spontaneous fusion between lymphoid and carcinoma cells in vivo has been described previously. Splenocytes from mice treated with LPS or mitogen have been reported to fuse better with myeloma cells using PEG as fusion agent than splenocytes from untreated mice. We report a phenomenon where immunization of mice with formalin treated, whole Haemophilus paragallinarum bacteria induced spontaneous fusion of splenocytes with myeloma cells in vitro, without the aid of any fusion agent. Co-immunization of mice with H. paragallinarum and an unrelated antigen (hen's egg white lysozyme), followed by co-culturing of the immune splenocytes with SP2/0 myeloma cells, yielded stable hybridoma cell lines producing anti-lysozyme antibodies. H. paragallinarum may be used in adjuvants to simplify the production of monoclonal antibodies, and the discovery of a promotional activity of a gram negative bacterium on cell fusion and hybridoma formation may shed new light on spontaneous fusion as a natural immune phenomenon in cancer.

Prognostic relevance of urinary neopterin in non-Hodgkin's lymphomas

Neopterin excretion levels were assessed in 66 consecutive patients affected by non-Hodgkin's lymphomas (NHL). The logarithm of the mean value of the whole series was 2.71 (log [mumol neopterin/mol creatinine]), significantly higher (P less than 0.001) than the control value (2.12). Fifty-six of 66 patients had a raised excretion of neopterin in amounts statistically related to the stage of disease. The mean value (2.51) of patients in Stages I-II was lower than the mean value (2.86) of patients in Stage III-IV (P less than 0.001). The 2-year probability of survival was 64% for patients in Stages I-II and 34% for patients in Stages III-IV. However, patients with lower neopterin excretion (less than 2.65) fared better than patients with higher neopterin excretion, regardless of the stage. Longitudinal analysis showed a trend toward a correlation between response to therapy and neopterin excretion. In NHL, the raised neopterin excretion appears to be a consequence of activation of the host immune system rather than a product of the malignant cells. But this excessive activation of the monocytes-macrophages, as reflected by urinary neopterin levels, is not accompanied by a better outcome. In conclusion, although neopterin cannot be considered a typical tumor marker, nevertheless it is an useful prognostic marker in NHL.

Pulmonary alveolar proteinosis. Occurrence with metastatic melanoma to lung

Pulmonary alveolar proteinosis is characterized by excessive accumulation of surfactant-like material in the alveoli, resulting in part from defective alveolar clearance by macrophages. We present a case of alveolar proteinosis in a patient with malignant melanoma metastatic to lung and discuss possible alteration in macrophage function in the pathogenesis of these two concomitant processes.

HLA-DR antigen expression on melanoma metastases and the course of the disease

Melanoma cells freshly isolated from regional lymph node metastases of 59 stage II malignant melanoma patients were analyzed by indirect immunofluorescence staining with monoclonal antibody TAL 1B5, detecting the HLA-DR alpha chain. The expression of HLA-A,B,C antigens, using antibody W6/32, was also investigated in 45 of these cases. There were no substantial differences in the course of the disease with respect to the percentage of positive cells. In 13 malignant melanoma patients two to four simultaneous and/or successive metastases (both locoregional and distant-subcutaneous) were analysed for HLA-DR. With simultaneous metastases (7 cases) the percentage of HLA-DR-positive cells was mostly very similar, and in no case was there more than 25% variation. As to successive metastases (9 cases) the percentage of HLA-DR-positive cells remained practically unchanged or decreased during the course of the disease.