Neoplastic Cell Clone Research Articles

Different Patterns of Vascularization in Preinvasive States and at the Initial Stages of Invasive Growth of the Neoplasms.

Tissue samples obtained during surgery from 90 patients with malignant neoplasms of various localizations were studied (the presence of precancerous dysplastic alterations and their transition to invasive cancer in the slides were obligatory condition). In addition to traditional histological methods, immunohistochemical reactions for detection of HIF-1α, GLUT1, CAIX, and CD31 were performed. At the precancerous stage including cancer in situ, progressive signs of reduced blood vessel density and hypoxia were observed. At the earliest stages of invasion, hypoxia was compensated by abundant vascularization of the stroma, which was confirmed by disappearance of hypoxia markers in tumor cells and their persistence in the deep layers of the tumor far from blood vessels. At the same time, the ischemic phenotype was preserved in tumor cells even in abundantly vascularized stroma, which can attest to deep metabolic changes in some tumor cells similar to the Warburg effect. Thus, the initial stages of carcinogenesis are associated with reduction of the vascular network up to the complete absence of blood vessels in the cancer in situ. After migration to the vascularized subepithelial stroma, e.g., having started invasion that compensated for hypoxia, the tumor cells no longer expressed markers of hypoxia, except the cells located far from blood vessels. In parallel, neoplastic cell clones that presumably have changed their phenotype and transformed their metabolism similar to the Warburg effect were detected. In the deep layers of the tumors, these cells coexist in different proportions. Analysis of the content of these cells, their alternation, and mutual transformation will be very valuable for estimating the sensitivity of tumor cells to therapeutic measures.

Mesenchymal stromal cell senescence in haematological malignancies.

Acute myeloid leukaemia (AML), chronic lymphocytic leukaemia (CLL), and multiple myeloma (MM) are age-related haematological malignancies with defined precursor states termed myelodysplastic syndrome (MDS), monoclonal B-cell lymphocytosis (MBL), and monoclonal gammopathy of undetermined significance (MGUS), respectively. While the progression from asymptomatic precursor states to malignancy is widely considered to be mediated by the accumulation of genetic mutations in neoplastic haematopoietic cell clones, recent studies suggest that intrinsic genetic changes, alone, may be insufficient to drive the progression to overt malignancy. Notably, studies suggest that extrinsic, microenvironmental changes in the bone marrow (BM) may also promote the transition from these precursor states to active disease. There is now enhanced focus on extrinsic, age-related changes in the BM microenvironment that accompany the development of AML, CLL, and MM. One of the most prominent changes associated with ageing is the accumulation of senescent mesenchymal stromal cells within tissues and organs. In comparison with proliferating cells, senescent cells display an altered profile of secreted factors (secretome), termed the senescence-associated-secretory phenotype (SASP), comprising proteases, inflammatory cytokines, and growth factors that may render the local microenvironment favourable for cancer growth. It is well established that BM mesenchymal stromal cells (BM-MSCs) are key regulators of haematopoietic stem cell maintenance and fate determination. Moreover, there is emerging evidence that BM-MSC senescence may contribute to age-related haematopoietic decline and cancer development. This review explores the association between BM-MSC senescence and the development of haematological malignancies, and the functional role of senescent BM-MSCs in the development of these cancers.

Monoclonal gammopathy of renal significance: Spectrum of diseases and approach to a case.

The occurrence of kidney diseases associated with a monoclonal gammopathy in the absence of symptomatic multiple myeloma is increasingly recognized. When the kidney is involved, the monoclonal etiology of these diseases results in clinical and laboratory features distinct from those of other disease, necessitating the nomenclature monoclonal gammopathy of renal significance (MGRS). The detection of these monoclonal diseases involving the kidney is important since they are poorly responsive to conventional immunosuppression and instead require clone-directed therapy. The new International Kidney and Monoclonal research group consensus definition of MGRS includes all proliferative conditions of B cells and/or plasma cells. Renal lesions due to monoclonal immunoglobulins are quite capable of progression with resulting end-stage renal disease development. Hence, these lesions require therapeutic intervention even if they do not satisfy myeloma criteria or the presence of any myeloma defining event. The spectrum of renal lesions that can be observed in a case of MGRS is wide and mirrors the list that may be seen in a case of any plasma cell neoplasm. This includes Ig light chain, heavy chain, and heavy and light chain amyloidosis; immunotactoid glomerulonephritis (GN); monoclonal immunoglobulin deposition disease including light chain, heavy chain, or heavy and light chain disease; light chain proximal tubulopathy; crystal-storing histiocytosis; proliferative GN with monoclonal immunoglobulin deposits; C3 glomerulopathy with monoclonal gammopathy and cast nephropathy. The initial approach after histological assessment is based on presence or absence of monoclonal immunoglobulin deposits. If monoclonality is evident, it is important to distinguish between conditions with deposition of intact immunoglobulin molecule or light chains only. The treatment of MGRS is directed at the underlying neoplastic B-cell or plasma cell clones.

Comparison of E-cadherin with STAT3 and apoptosis regulators: Bak and Bcl-xL in endometrioid adenocarcinomas of different ER-alpha immunoprofile

E-cadherin is a factor of good prognosis in endometrioid adenocarcinomas, while STAT3 is an oncogenic driver of carcinogenesis. E-cadherin, Bak, Bcl-xL and STAT3 were immunohistochemically detected in 78 human endometrioid adenocarcinomas. E-cadherin correlated with STAT3 (p <. 001, r = 0.537) as well as Bak (p = .005, r = 0.314) and Bcl-xL (p = .002, r = 0.340) in the whole study group. In G2 tumors, E-cadherin associated with Bak (p = .021, r = 0.319), Bcl-xL (p = .026, r = 0.309) and STAT3 (p <.001, r = 0.513) but not in G3 adenocarcinomas. E-cadherin correlated with Bak and Bcl-xL in both G1- and estrogen receptor (ER)-negative tumors with significant relation of E-cadherin and STAT3 in G1- and ER-negative tumors. Antigrowth synergy of expression was preserved for antiapoptotic Bak and proliferation-suppressing E-cadherin in IA adenocarcinomas (p = .031, r = 0.342) with no significance between Bak and E-cadherin or STAT3 and emerging correlation between E-cadherin and Bcl-xL in IB + II tumors instead (p = .003, r = 0.472). E-cadherin correlated with Bak and Bcl-xL in ER-positive adenocarcinomas (p = .002, r = 0.382 and p <.001, r = 0.439, respectively) but not in ER-negative tumors. In conclusion, expression deregulation of studied proteins is reflected in selective loss of correlation between suppressors of tumor growth (E-cadherin and Bak) presumably due to progressing impairment of growth-inhibitory properties of clone of neoplastic cells within higher staging and poorer differentiation.

Regulation of miR-483-3p by the O-linked N-acetylglucosamine transferase links chemosensitivity to glucose metabolism in liver cancer cells

The miR-483-3p is upregulated in several tumors, including liver tumors, where it inhibits TP53-dependent apoptosis by targeting the pro-apoptotic gene BBC3/PUMA. The transcriptional regulation of the miR-483-3p could be driven by the β-catenin/USF1 complex, independently from its host gene IGF2, and we previously demonstrated that in HepG2 hepatoblastoma cells carrying wild-type TP53 the upregulation of the miR-483-3p overcomes the antitumoral effects of the tumor-suppressor miR-145-5p by a mechanism involving cellular glucose availability. Here we demonstrate that in HepG2 cells, the molecular link between glucose concentration and miR-483-3p expression entails the O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT), which stabilizes the transcriptional complex at the miR-483 promoter. HepG2 cells showed reduced miR-483-3p expression and increased susceptibility to 5-fluorouracil (5-FU)-induced apoptosis in presence of the inhibitor of glycolysis 2-deoxy-d-glucose (2-DG). However, in vivo experiments showed that HepG2 cells with higher miR-483-3p expression were selected during tumor progression regardless of 5-FU treatment. Furthermore, treatment with 2-DG alone did not significantly reduce HepG2 xenograft load in immunodeficient mice. In conclusion, we show that in HepG2 cells glucose uptake increases the expression of the oncogenic miR-483-3p through the OGT pathway. This suggests that depletion of the miR-483-3p may be a valuable therapeutic approach in liver cancer patients, but the use of inhibitors of glycolysis to achieve this purpose could accelerate the selection of resistant neoplastic cell clones.

Oncolytic Virotherapy for Thyroid Cancer: Will it Translate to the Clinic?

Observations that viruses can induce tumor regression date back to the beginning of the 20th century [1] and the use of viruses for cancer treatment has been theorized since then ; however only in the late 1990s advancement in viral manipulation technologies together with a better understanding of the molecular alterations in cancer cells allowed the development of oncolytic viruses (virotherapy). So far, dozen of viruses have been tested for their oncolytic activity. Oncolytic viruses (OVs) have several potential benefits as anticancer therapeutics: tumorselective replication, amplification of the input dose, efficacy independent of resistance to current anticancer therapies. OVs do not contribute to the generation of neoplastic cell clones or treatment resistance [2]. To generate viruses able to selectively replicate in neoplastic cells, different viral strain and several strategies have been exploited [3]. Viral strains displaying a natural oncotropism have also been tested [2]. The clinical trials performed in the last two decades have demonstrated the safety of OVs and substantial antineoplastic effects. The best clinically evaluated replication-selective oncolytic viruses to date are the mutant adenoviruses dl1520, ONYX-015 and H101 (Oncorine; Shanghai Sunway Biotech). These mutants bear a E1B55K gene deletion, enabling the mutants to replicate only in cells with functional inactivation of p53. E1B55K viral gene is required for other important functions and its deletion greatly impairs viral replication [4], explaining the modest activity as single agent reported in clinical trials. However, dl1520 and H101 were shown to enhance the effects of chemotherapeutic drugs and on the base of these results, H101 was licensed in China for the treatment of head and neck cancers in combination with cisplatin and 5-FU [5,6]. The majority of thyroid cancers are well differentiated papillary or follicular carcinomas with a good cure rate and an excellent prognosis. In contrast, anaplastic thyroid carcinoma (ATC) is one of the most aggressive human cancers with a short survival time. Multimodality therapy (surgery, chemotherapy and radiotherapy) has shown a limited success and although ATC accounts for only 2% of thyroid carcinoma, it contributes up to 50% of thyroid cancer deaths [7]. Not surprisingly, the studies with OVs have been focused to the treatment of ATC. The first studies testing selective replicating adenoviruses were performed by our group using dl1520 mutant alone or in combination with paclitaxlel, doxorubicin [8] and radiotherapy [9]. Lovastatin, a cholesterol-lowering drug also acting as an inhibitor of p21 ras activity was used by us in conjunction with dl1520 to improve viral cytotoxicity. The combination significantly reduced the growth of ATC xenografts [10]. It is worth noting that p53 inactivation frequency in ATCs is about 50%, with a strong limitation of the therapeutic range for dl1520. Moreover, the studies were conducted in a variety of long established ATC cells lines, some of them successively identified as derived from other tumors. Despite these limitations, the studies with dl1520 have shown that OVs hold a potential benefit for the treatment of ATC. Abbosh et al. have used an oncolytic adenovirus selectively replicating in cells with an active Wnt/β-catenin pathway showing an oncolytic activity and a prolonged survival of animals bearing ATC xenografts [11], confirming the efficacy of the approach. Due to the attenuated replication potential and the limited fraction of ATCs with a nonfunctional p53 pathway, we evaluated dl922–947, a more effective second generation oncolytic adenovirus. dl922–947 bears a deletion of 24bp in E1A-Conserved Region 2 (CR2) [12].

Idiopathic Hypereosinophilic Syndrome/Eosinophilic Leukaemia (Case Report): A Challenge to Diagnose

Hypereosinophilic syndrome (HES) was first described by Hardy and Anderson in 1968 . HES may result either from eosinophilic differentiation of a clone of neoplastic cells or from reactive eosinophilia. It appears lightly that in many patients idiopathic HES is actually a chronic myeloproliferative disorder. There is vaguely overlapping clinico-pathological picture of HES with (Chronic eosinophilic leukaemia) CEL which often adds to diagnostic confusion. In 2001, the World Health Organization (WHO) proposed a set of criteria that distinguish CEL from HES. An evidence of genetic clonality of eosinophils or an increase in blast cells in blood or bone marrow is mandatory for diagnosis of CEL, while no specific diagnostic tests exists for HES, making it an entity of exclusion. A 36 year old female presented with intermittent fever and dry cough since two months. Clinical examination revealed mild pallor with hepatosplenomegaly. Chest examination showed bilateral basal crepitations. The patient was subjected for hematological, biochemical and radiological assessment. The peripheral smear and bone marrow aspirates revealed presence of eosinophilic precursors with predominance of eosinophiloblasts associated with eosinophilic myelocytes, metamyelocytes, a few myeloblasts and lymphocytes, the features of which are in favour of CEL. CEL, a rare myeloproliferative entity and its presentation with pulmonary manifestations is still rare in India. Hence, we present this rare entity along with review of available literature.

Development of a highly-sensitive multi-plex assay using monoclonal antibodies for the simultaneous measurement of kappa and lambda immunoglobulin free light chains in serum and urine

Monoclonal κ and λ immunoglobulin free light chain (FLC) paraproteins in serum and urine are important markers in the diagnosis and monitoring of B cell dyscrasias. Current nephelometric and turbidimetric methods that use sheep polyclonal antisera to quantify serum FLC have a number of well-observed limitations. In this report, we describe an improved method using specific mouse anti-human FLC monoclonal antibodies (mAbs). Anti-κ and anti-λ FLC mAbs were, separately, covalently coupled to polystyrene Xmap® beads and assayed, simultaneously, in a multi-plex format by Luminex® (mAb assay). The mAbs displayed no cross-reactivity to bound LC, the alternate LC type, or other human proteins and had improved sensitivity and specificity over immunofixation electrophoresis (IFE) and Freelite™. The assay gives good linearity and sensitivity (<1mg/L), and the competitive inhibition format gave a broad calibration curve up to 437.5mg/L and prevented anomalous results for samples in antigen excess i.e. high FLC levels. The mAbs displayed good concordance with Freelite™ for the quantitation of normal polyclonal FLC in plasma from healthy donors (n=249). The mAb assay identified all monoclonal FLC in serum from consecutive patient samples (n=1000; 50.1% with monoclonal paraprotein by serum IFE), and all FLC in a large cohort of urine samples tested for Bence Jones proteins (n=13090; 22.8% with monoclonal κ, 9.0% with monoclonal λ, and 0.8% with poly LC detected by urine IFE). Importantly this shows that the mAbs are at least close to the ideal of detecting FLC from all patients and neoplastic plasma cell clones. Given the overall effectiveness of the anti-FLC mAbs, further clinical validation is now warranted on serial samples from a range of patients with B cell disorders. Use of these mAbs on other assay platforms should also be investigated.

Angiogenic Signalling Pathways Altered in Gliomas: Selection Mechanisms for More Aggressive Neoplastic Subpopulations with Invasive Phenotype

The angiogenesis process is a key event for glioma survival, malignancy and growth. The start of angiogenesis is mediated by a cascade of intratumoural events: alteration of the microvasculature network; a hypoxic microenvironment; adaptation of neoplastic cells and synthesis of pro-angiogenic factors. Due to a chaotic blood flow, a consequence of an aberrant microvasculature, tissue hypoxia phenomena are induced. Hypoxia inducible factor 1 is a major regulator in glioma invasiveness and angiogenesis. Clones of neoplastic cells with stem cell characteristics are selected by HIF-1. These cells, called “glioma stem cells” induce the synthesis of vascular endothelial growth factor. This factor is a pivotal mediator of angiogenesis. To elucidate the role of these angiogenic mediators during glioma growth, we have used a rat endogenous glioma model. Gliomas induced by prenatal ENU administration allowed us to study angiogenic events from early to advanced tumour stages. Events such as microvascular aberrations, hypoxia, GSC selection and VEGF synthesis may be studied in depth. Our data showed that for the treatment of gliomas, developing anti-angiogenic therapies could be aimed at GSCs, HIF-1 or VEGF. The ENU-glioma model can be considered to be a useful option to check novel designs of these treatment strategies.

Allele Specific Locked Nucleic Acid Quantitative PCR (ASLNAqPCR): An Accurate and Cost-Effective Assay to Diagnose and Quantify KRAS and BRAF Mutation

The use of tyrosine kinase inhibitors (TKIs) requires the testing for hot spot mutations of the molecular effectors downstream the membrane-bound tyrosine kinases since their wild type status is expected for response to TKI therapy. We report a novel assay that we have called Allele Specific Locked Nucleic Acid quantitative PCR (ASLNAqPCR). The assay uses LNA-modified allele specific primers and LNA-modified beacon probes to increase sensitivity, specificity and to accurately quantify mutations. We designed primers specific for codon 12/13 KRAS mutations and BRAF V600E, and validated the assay with 300 routine samples from a variety of sources, including cytology specimens. All were analyzed by ASLNAqPCR and Sanger sequencing. Discordant cases were pyrosequenced. ASLNAqPCR correctly identified BRAF and KRAS mutations in all discordant cases and all had a mutated/wild type DNA ratio below the analytical sensitivity of the Sanger method. ASLNAqPCR was 100% specific with greater accuracy, positive and negative predictive values compared with Sanger sequencing. The analytical sensitivity of ASLNAqPCR is 0.1%, allowing quantification of mutated DNA in small neoplastic cell clones. ASLNAqPCR can be performed in any laboratory with real-time PCR equipment, is very cost-effective and can easily be adapted to detect hot spot mutations in other oncogenes.

The stem cell fitness landscape and pathways of molecular leukemogenesis

The relative risk of clonal evolution to either myelodysplasia (MDS) or acute myelogenous leukemia (AML) is high in patients with chronic bone marrow failure. From 10 to 20% of acquired aplastic anemia survivors will develop clonal evolution within the decade following their diagnosis as will 40% of patients with some of the inherited bone marrow failure syndromes. Studies on bone marrow failure states have provided some perspective on molecular pathogenesis of marrow failure and have also provided insights on the adaptive nature of clonal evolution. We review the scientific evidence validating this model, emphasize the importance of the fitness landscape in the stem cell pool, outline the clinical and investigative implications of the model, suggest that the lack of fitness in the starting pool accounts for the phenomenon of oncogene addiction, promote the value of the model for the evaluation of prevention strategies, and argue that experiments focusing attention on the relative phenotypes of neoplastic stem cell clones and pools of unfit stem cells from which they evolved will provide a useful paradigm of carcinogenesis in general.

ABO discrepancy in an elderly patient with IgA kappa-type multiple myeloma

Dear Editor, Multiple myeloma, a hematologic malignancy characterized by the proliferation of a neoplastic plasma cell clone in the bone marrow, accounts for 10% of hematologic malignancies [1]. The common presenting features, such as anemia, bone pain, hypercalcemia, and increasing susceptibility to infections, are caused by the infiltration of plasma cells and changes in plasma protein [2]. Large amounts of monoclonal protein and a loss of functional antibody production can cause immunological dysfunction and distinct laboratory findings. In multiple myeloma, an ABO discrepancy can result from protein abnormalities causing rouleaux formation or pseudoagglutination in the blood group test [3]. Here, we report a novel case of ABO discrepancy in a patient with IgA kappatype multiple myeloma caused by the loss of isoagglutinin. A 78-year-old woman who had been suffering from multiple myeloma (IgA, kappa type) for 8 years was admitted for a scheduled chemotherapy. The total protein (9.6 g/dl) was elevated due to a large amount of IgA (4,430 mg/dl), whereas, the levels of uninvolved immunoglobulins were reduced (IgG, 236 mg/dl and IgM, <20 mg/dl). In the peripheral blood smear, rouleaux formation was prominent; moreover, her decreased hemoglobin level (4.5 g/ml) necessitated blood transfusion. On blood group testing, the cell type was B+; but anti-A was not detected in her serum. To confirm her blood type, the polymerase chain reaction with restriction fragment length polymorphism was performed and her genotype of ABO*B/O was revealed. She was transfused with five units of B+irradiation-filtered packed red cells without complication before initiating conventional-dose chemotherapy. ABO discrepancies can be caused by the loss of expected anti-A or anti-B isoagglutinins with agammaglobulinemia or hypogammaglobulinemia in primary and secondary immunodeficiencies [4–6]. In multiple myeloma, the levels of the uninvolved immunoglobulin isotypes are usually reduced, but an ABO discrepancy due to the loss of isoagglutinin in multiple myeloma is rarely reported. To the best of our knowledge, only a single study has reported on multiple myeloma with ABO discrepancies due to the loss of isoagglutinins (three cases) [7]. While the monoclonal chains in these cases were the IgG kappa, free lambda, and IgG lambda types, respectively, our patient had IgA kappatype monoclonality. A feature common to all of these cases was the severe loss of uninvolved IgM (Table 1). The isoagglutinins produced by blood group A or B patients consist predominantly of IgM molecules [8]. Therefore, the loss of IgM in these patients would be the reason why the Hwi-Joong Yoon and Tae Sung Park equally contributed to this work as corresponding authors.

Senescence and life span

Senescence is a general cellular process that occurs as a response to stress and damage. It forms an alternative response of cells to damage that might otherwise cause programmed cell death. Whereas telomere shortening leading to telomere dysfunction was the first described cause of senescence, it is now known that senescence can result from many sources of damage. Senescent cells are found in tissues in vivo, but the cause of senescence in these cells is mostly unknown. In many cases, senescence may be the result of the action of activated oncogenes in cells. By preventing activated oncogenes from initiating a clone of neoplastic cells, senescence acts as a protective mechanism against cancer development. Until recently, the fate of senescent cells in vivo was unknown, but new evidence indicates that they are cleared by components of the innate immune system. In this way, senescence and apoptosis act as parallel pathways by which severely damaged cells are eliminated from the body. Some senescent cells persist in tissues, in some cases increasing in frequency as a function of age. It is hypothesized that these persistent senescent cells have adverse effects on tissue function. If so, senescence may be an example of antagonistic pleiotropy, providing an anticancer mechanism in early life but having adverse effects on tissue function in late life. Much more research is needed to address the broader question of the overall impact of senescence on life span.

A Comment on Ion Channels as Pharmacological Targets in Oncology

A Comment on Ion Channels as Pharmacological Targets in Oncology

TNF-α induces leukemic clonal evolution ex vivo in Fanconi anemia group C murine stem cells

The molecular pathogenesis of the myeloid leukemias that frequently occur in patients with Fanconi anemia (FA) is not well defined. Hematopoietic stem cells bearing inactivating mutations of FA complementation group C (FANCC) are genetically unstable and hypersensitive to apoptotic cytokine cues including IFN-gamma and TNF-alpha, but neoplastic stem cell clones that arise frequently in vivo are resistant to these cytokines. Reasoning that the combination of genetic instability and cytokine hypersensitivity might create an environment supporting the emergence of leukemic stem cells, we tested the leukemia-promoting effects of TNF-alpha in murine stem cells. TNF-alpha exposure initially profoundly inhibited the growth of Fancc-/- stem cells. However, longer-term exposure of these cells promoted the outgrowth of cytogenetically abnormal clones that, upon transplantation into congenic WT mice, led to acute myelogenous leukemia. TNF-alpha induced ROS-dependent genetic instability in Fancc-/- but not in WT cells. The leukemic clones were TNF-alpha resistant but retained their characteristic hypersensitivity to mitomycin C and exhibited high levels of chromosomal instability. Expression of FANCC cDNA in Fancc-/- stem cells protected them from TNF-alpha-induced clonal evolution. We conclude that TNF-alpha exposure creates an environment in which somatically mutated preleukemic stem cell clones are selected and from which unaltered TNF-alpha-hypersensitive Fancc-/- stem cells are purged.

Immunohistochemical detection of CD 95 (Fas) & Fas ligand (Fas-L) in plasma cells of multiple myeloma and its correlation with survival

Multiple myeloma (MM) is a malignant disease resulting from an uncontrolled proliferation of a neoplastic plasma cell clone in the bone marrow, which might also be induced by the loss of control on apoptosis. Fas ligand (Fas-L), a member of the tumor necrosis factor family, induces apoptosis mediated via its transmembrane death receptor Fas (Apo-1/CD95) antigen. In the present study, immunostaining was performed on the initial diagnostic bone marrow biopsies of 36 MM patients (1 stage I, 5 stage II, 30 stage III), to evaluate the distribution of Fas receptor and Fas-L on malignant plasma cells. Both Fas and Fas-L were positive in 13 cases and negative in 3, whereas 10 cases were Fas-negative, Fas-L-positive and 10 were Fas-positive, Fas-L-negative. Although no association was found between the expression of Fas receptor or Fas-L and overall survival, Fas-L positivity was significantly associated with a shorter event-free survival (p = 0.0335). In this study, it has been shown that the expression of Fas-L, in malignant plasma cells of myeloma patients significantly shortens the event-free survival, indicating that the defect in apoptosis might be associated with disease progression in MM.

Ph-Chromosome-positive chronic myeloid leukemia with associated bone marrow mastocytosis

The concurrent development of chronic myeloid (CML) or myelomonocytic (CMML) leukemia in patients with systemic mastocytosis (SM) is a well recognized phenomenon. Although the leukemia often resembles CML in morphological and in clinical terms, a Ph-Chromosome-positive variant has not been reported in SM so far. We here describe a 43-year-old female patient with typical Ph-Chromosome-positive CML in whom a co-existing bone marrow mastocytosis, a special subvariant of SM, was diagnosed. RT-PCR analysis revealed the typical p210 kDa form of BCR/ABL in leukemic cells. The diagnosis SM was based on the typical focal aggregates of spindle-shaped mast cells (MC) in the bone marrow, expression of CD25 in MC, and the c- kit mutation D816V, which was detectable in microdissected bone marrow MC, but not in microdissected leukemic cells, suggesting the presence of two different (sub)clones of neoplastic cells. Therapy with the BCR/ABL-targeting drug Imatinib (STI571) resulted in complete cytogenetic remission of CML. Together, our case provides further evidence for the biologic diversity of leukemias that may occur in patients with SM. The exact knowledge of the pathology and target-profile of the associated leukemias in SM have important therapeutic implications.

Therapy strategies for multiple myeloma: current status

Multiple myeloma (MM) is characterized by infiltration of bone marrow with a clone of neoplastic plasma cells. Impaired hematopoiesis and reduced production of functional immunoglobulins, as well as the induction of pathognomonic osteolytic lesions primarily contribute to the morbidity of patients with MM. Conventional chemotherapy is the treatment of choice for older patients, whereas those under 60 years benefit significantly from high-dose therapy followed by stem-cell rescue. The use of tandem transplantation, developed to further escalate the conditioning dose, has achieved additional improvement in survival. Interferon-alpha and glucocorticoids are effective as maintenance measures in MM but remain controversial because of their associated high costs and considerable toxicity. The resurrection of an old drug, thalidomide, for the therapy of MM and the development of potent immunomodulatory derivatives are highly promising new treatments that target MM cell-host interactions and the bone-marrow microenvironment, as well as the myeloma cell itself. The importance of the use of bisphosphonates for the prevention or amelioration of skeletal complications and hypercalcemia is well established. New generations of bisphosphonates show potent antitumor activity, again emphasising the importance of targeting the microenvironment of the plasma-cell clone.

Epithelial carcinogenesis: challenging monoclonality.

How carcinomas begin remains unclear, but experimental data do not entirely exclude the participation of more than one clone of neoplastic cells, even in relatively advanced epithelial tumour growth. Microdissection and new PCR clonality assays exploiting X-linked polymorphisms, some of which (including XIST) are expressed in RNA, create investigational opportunities complementary to other molecular analyses, but a reliable in situ assay of X-inactivation remains desirable. The necessity for stringent controls in clonality analysis is emphasized. While it may be possible to reconcile 'pluriclonal' (oligoclonal or polyclonal) carcinogenesis with widely accepted paradigms of genetic/epigenetic change and clonal selection in epithelial neoplasia, it deserves critical study as novel carcinogenic mechanisms would be implied.

Immunomodulatory gene therapy for haematological malignancies.

Immunomodulatory gene therapy for haematological malignancies.