Claudin 6 Is a Positive Marker for Atypical Teratoid/Rhabdoid Tumors

Atypical teratoid/rhabdoid tumors (AT/RTs) are highly aggressive pediatric brain tumors characterized by the presence of rhabdoid cells and negative immunostaining for INI1 (BAF47). Histogenesis is unknown and diagnosis can be challenging because of their extreme morphological and immunophenotypic heterogeneity. Currently no signature markers other than INI1 loss have been identified. To search for possible candidate proteins of interest in AT/RTs, Affymetrix GeneChip® microarrays were utilized to investigate nine AT/RTs vs. 124 other tumor samples. The most distinctive gene identified was claudin 6 ( CLDN6 ), a key component of tight junctions. CLDN6 showed moderate or higher mRNA expression in eight of nine AT/RTs, with little to no expression in 114 of 115 other tumors. Average expression was 38-fold higher in AT/RTs vs. other samples. Immunohistochemical (IHC) staining of 33 tumor specimens found positive membrane staining in seven of seven AT/RTs, and was negative in 26 of 27 other brain tumor samples. Notably, none of the 16 medulloblastomas/primitive neuroectodermal tumors showed IHC staining for CLDN6. IHC staining results closely matched the level of mRNA expression detected by microarray. CLDN6 may be a useful positive marker to help further identify AT/RTs for diagnostic and treatment purposes.     

Rhabdoid Tumors: An Initial Clue to the Role of Chromatin Remodeling in Cancer

The discovery of biallelic, inactivating SMARCB1 mutations in rhabdoid tumors (RTs) over a decade ago represented the first recognized link between chromatin remodeling and tumor suppression. SMARCB1 is a core subunit of the SWI/SNF chromatin remodeling complex, and the recent emergence of frequent mutations in genes that encode subunits of this complex across a wide variety of cancers suggests that perturbation of this chromatin remodeling complex constitutes a key driver of cancer formation. Despite the highly aggressive nature of RTs, they are genetically simple cancers that appear to lack chromosomal instability and contain very few mutations. Indeed, the mutation rate in RTs is among the lowest of all cancers sequenced, with loss of SMARCB1 as essentially the sole recurrent event. Given the genetic simplicity of this disease, understanding the chromatin dysregulation caused by SMARCB1 loss may provide more general insight into how epigenetic alterations can contribute to oncogenic transformation and may reveal opportunities for targeted therapy not only of RT but also the variety of other SWI/SNF mutant cancers.     

Factors Affecting the Outcomes of Patients with Malignant Rhabdoid Tumors: A Population-Based Study

Objective: Malignant rhabdoid tumor (MRT) is a rare but aggressive malignancy. It has been a long time since data on this tumor have been updated.Methods: We retrospectively reviewed patients from the SEER database who were pathologically diagnosed with MRT and analyzed incidence rates, clinical features and survival using Stata 12.0.Results: In total, 544 patients were included in the epidemiological analysis. There were two peak periods of MRT incidence: patients younger than 4 years and those older than 70 years. Further survival analysis showed that the survival of children (especially younger than 1 year) was markedly worse than that of adults (P<0.01), and different primary sites were associated with different age groups and survival outcomes. The central nervous system (CNS) was the most common primary site (50.00%), followed by the kidney (15.66%). Patients with MRTs that originated from the digestive system experienced worse survival outcomes than those with MRTs originating from other locations. Primary site surgery conferred survival benefits to patients with renal and digestive system MRTs (HR = 0.06, CI: 0.02-0.23, P<0.01; HR=0.10, CI: 0.02-0.48, P<0.01), whereas radiotherapy conferred benefits to patients with CNS, bone and soft tissue MRTs (HR=0.22, CI: 0.15-0.34, P<0.01; HR=0.44, CI: 0.21-0.90 P=0.03).Conclusions: Our results indicate that age and the primary site of MRT are critical clinical factors that affect patient survival and treatment choices. Primary site tumor resection should be considered for renal and digestive system MRTs, and systematic therapy, including surgery and radiotherapy, should be recommended for the treatment of CNS, bone and soft tissue MRTs.     

Overview of Neuroendocrine Cells and Tumors

The diffuse neuroendocrine system (DNES) is composed of cells and tumors with secretory granules ranging from 50–400 nm in diameter. Members of the DNES commonly stain for chromogranin and synaptophysin by immunohistochemistry and may express a variety of peptide hormones. Recent studies have shown that the proprotein convertases (proconvertases or PCs) are good broad-spectrum markers for members of the DNES. Gene expression can be readily detecting in neuroendocrine cells and tumors byin situ hybridization (ISH). Newer techniques such asin situ polymerase chain reaction (PCR) can be used to detect gene products that are expressed in low copy numbers in neuroendocrine cells. The concept of multidirectional differentiation is an important notion that helps to explain multiple patterns of phenotypic expression observed in some neuroendocrine tumors. Presented at the Endocrine Pathology Society—USCAP Meeting, Washington, DC, March 23, 1996.     

Therapeutic Activity of NK Cells against Tumors

While it is generally accepted that natural killer (NK) cells, by killing tumor cells in the circulation, represent a first line of defense against metastases, their therapeutic activity against established tumors has been limited. In this review, we describe studies to improve the therapeutic effectiveness of activated NK cells in both animal models and clinical trials to better understand the biological problems that limit their effectiveness.     

Subpopulation of Colorectal Adenocarcinoma Cells Co-Expressing CD133 and Cancer Stem Cells Markers of Other Tumors

Co-expression of colorectal adenocarcinoma cancer stem cells marker CD133 and a set of surface molecules described in published reports as possible cancer stem cell markers of other solid tumors was analyzed by fl ow cytometry. Minor cell populations expressing CD29, CD34, CD90, and CD117 against the background of CD133 expression were detected in cancer cells suspensions from the patients with colorectal adenocarcinoma. Our fi ndings suggest that these markers can be used as additional markers of cancer stem cells of human colorectal adenocarcinoma.     

Cytopathology and Ultrastructure of Primary Rhabdoid Tumor of Lung

This case report presents the light microscopy, immunocytochemistry, and ultrastructure of the first unequivocal extrarenal rhabdoid tumor occurring in lung. Smears and cell blocks prepared from a fine-needle aspiration biopsy show the cyto-pathological features of this unusual neoplasm, in this case presenting in a 74-year-old male. Electron microscopy of the surgically resected circumscribed pulmonary mass assisted in establishing the diagnosis by demonstrating the considerable accumulation of cytoplasmic intermediate filaments that characterize cells in extrarenal rhabdoid tumor and account for the hyaline “inclusion” in this particular lesion.     

Rhabdoid differentiation of chromophobe renal cell carcinoma

AIMS: Rhabdoid change represents an aggressive form of divergent differentiation previously reported in conventional (clear-cell) and papillary renal cell carcinoma. This study aims to characterise rhabdoid differentiation in a case of chromophobe renal cell carcinoma (ChRCC) and to investigate its origin by genetic analysis. METHODS: A large tumour mass arising in the right kidney of a 76-year-old male was investigated using routine stains (H&E, Hale's colloidal iron), immunostains (vimentin, cytokeratin) and genetic analysis for loss of heterozygosity (LOH) on chromosomes 1, 2, 3p, 6q, 10q, 13q, 17q, 17p and 21q. RESULTS: The tumour mass was comprised of the following histological subtypes: (i) typical ChRCC, (ii) eosinophilic variant ChRCC and (iii) rhabdoid variant RCC. Tumour cells of all three different histological subtypes had a positive reaction to Hale's colloidal iron stain, negative immunostaining for vimentin and LOH on chromosomes 2, 10q, 13q and 17p. These results are consistent with a diagnosis of ChRCC and indicate a common genetic origin for all three histological cell types. CONCLUSIONS: This study confirms that the aggressive rhabdoid variant can arise from ChRCC, as has been previously demonstrated for conventional (clear-cell) and papillary RCC.     

Innate Immune Cells Induce Hemorrhage in Tumors during Thrombocytopenia

Platelets are crucial regulators of tumor vascular homeostasis and continuously prevent tumor hemorrhage through secretion of their granules. However, the reason for tumor bleeding in the absence of platelets remains unknown. Tumors are associated with inflammation, a cause of hemorrhage in thrombocytopenia. Here, we investigated the role of the inflamed tumor microenvironment in the induction of tumor vessel injury in thrombocytopenic mice. Using s.c. injections of vascular endothelial growth factor or tumor necrosis factor-α combined with depletion of neutrophils, we demonstrate that enhancing the opening of endothelial cell junctions was not sufficient to cause bleeding in the absence of platelets; instead, induction of tissue hemorrhage in thrombocytopenia required recruitment of leukocytes. Immunohistology revealed that thrombocytopenia-induced tumor hemorrhage occurs at sites of macrophage and neutrophil accumulation. Mice deficient in β₂ or β₃ integrins, which have decreased neutrophil and/or macrophage infiltration in their tumor stroma, were protected from thrombocytopenia-induced tumor hemorrhage, indicating that, in the absence of platelets, stroma-infiltrating leukocytes induced tumor vessel injury. This injury was independent of reactive oxygen species generation and of complement activation, as suggested by the persistence of tumor hemorrhage in C3- and nicotinamide adenine dinucleotide phosphate oxidase-deficient thrombocytopenic mice. Our results show that platelets counteract tumor-associated inflammation and that the absence of this platelet function elicits vascular injuries by tumor-infiltrating innate immune cells.Besides their fundamental role in primary hemostasis, platelets have been shown to support vascular barrier function and integrity during in vitro organ perfusion,¹ experimental angiogenesis,² cytotoxic T lymphocyte-dependent clearance of lymphocytic choriomeningitis virus,³ and inflammation.⁴ Recently, we reported that platelets are crucial regulators of tumor vascular homeostasis that continuously protect tumors from hemorrhaging and subsequent cell death.⁵ Prevention of tumor hemorrhage by platelets shows some similarities to that of hemorrhages at early stages of inflammatory reactions, suggesting that the inflamed microenvironment of tumors may play a role in the induction of tumor vessel damage in thrombocytopenic mice. In fact, in contrast to the mechanisms by which platelets promote primary hemostasis, neither firm platelet adhesion nor a platelet’s ability to form thrombi is required for maintaining vascular integrity in both inflamed skin and tumors.^4,5 We showed that transfusion of resting platelets prevented tumor bleeding in thrombocytopenic mice whereas transfusion of degranulated platelets did not.⁵ This pinpoints the importance of platelet granule secretion in protecting blood vessels. The soluble factors released by platelets may inhibit excessive endothelial permeability and/or prevent vascular injury induced by tumor-associated inflammation. Besides vascular endothelial growth factor (VEGF), a propermeability factor, platelet granules indeed also contain a variety of substances such as angiopoietin-1,^5,6 transforming growth factor-β,⁷ platelet basic protein,⁸ serpins,^9,10 serotonin,¹¹ or sphingosin-1-P ¹² that support vascular barrier function and/or have immunomodulatory properties.Here, we investigated the role of tumor-associated inflammation in tumor bleeding in thrombocytopenic mice. Our results show that stroma-infiltrating neutrophils and macrophages induce tumor vessel damage in thrombocytopenia. We further demonstrate that maintenance of vessel integrity by platelets exceeds their impact on endothelial junctions and involves inhibition of vascular damage induced by infiltrating leukocytes.     

Cytogenetic Abnormalities of Tumor-Associated Endothelial Cells in Human Malignant Tumors

Tumor blood vessels are thought to contain genetically normal and stable endothelial cells (ECs), unlike tumor cells, which typically display genetic instability. Yet, chromosomal aberration in human tumor-associated ECs (hTECs) in carcinoma has not yet been investigated. Here we isolated TECs from 20 human renal cell carcinomas and analyzed their cytogenetic abnormalities. The degree of aneuploidy was analyzed by fluorescence in situ hybridization using chromosome 7 and chromosome 8 DNA probes in isolated hTECs. In human renal cell carcinomas, 22–58% (median, 33%) of uncultured hTECs were aneuploid, whereas normal ECs were diploid. The mechanisms governing TEC aneuploidy were then studied using mouse TECs (mTECs) isolated from xenografts of human epithelial tumors. To investigate the contribution of progenitor cells to aneuploidy in mTECs, CD133⁺ and CD133⁻ mTECs were compared for aneuploidy. CD133⁺ mTECs showed aneuploidy more frequently than CD133⁻ mTECs. This is the first report showing cytogenetic abnormality of hTECs in carcinoma, contrary to traditional belief. Cytogenetic alterations in tumor vessels of carcinoma therefore can occur and may play a significant role in modifying tumor- stromal interactions.Tumor angiogenesis is necessary for solid tumor progression and metastasis.¹ Inhibiting the development of abnormal blood vessels associated with cancer is a promising therapeutic strategy for treating cancer. Bevacizumab, an antivascular endothelial growth factor-neutralizing antibody, prolongs the survival of patients with advanced cancer of the colon,² breast,³ or kidney⁴ when used with conventional chemotherapeutic drugs. However, such therapeutic treatments are not sufficient to cure cancer. One of the probable reasons is drug resistance caused by the compensatory response of tumor cells.⁵ Long-term suppression of the expression of one angiogenic protein can lead to the emergence of the expression of other angiogenic proteins. Secondary acquisition of resistance to antiangiogenic drugs by endothelial cells (ECs) might be another reason.An important concept in tumor angiogenesis is that tumor blood vessels contain ECs that are genetically normal and stable, unlike tumor cells, which typically display genetic instability.⁶ However, tumor vessels and tumor-associated ECs (TECs) differ from their normal counterparts in many respects.^{7,8,9,10,11,12} Tumor vessels have different structural characteristics, such as fewer pericytes, leakiness, and uneven thickness of the basement membrane.⁹ Furthermore, some studies have reported that TECs possess molecular characteristics distinct from those of normal ECs (NECs).^8,10,11 In addition, ECs derived from human renal cell carcinomas (RCCs) express biological features that are different from those of NECs.¹³It has been reported that ECs from hematopoietic tumors harbor chromosomal aberrations. In these tumors, TECs may transdifferentiate from hematopoietic tumor cells.^12,14We have reported that ECs in nonhematopoietic malignant tumors (melanoma and liposarcoma) are cytogenetically abnormal. In mouse xenograft models, fluorescence in situ hybridization (FISH) analysis shows that freshly isolated mouse TECs (mTECs) are aneuploid and have abnormal multiple centrosomes.^15,16 Our previous study showed that mTECs, unlike ECs in lymphomas with hematopoietic origin, did not transdifferentiate to or fuse with tumor cells because there were no human chromosomes from tumor cells in the mTEC nuclei. However, it remains to be elucidated whether these cytogenetic aberrations in mTECs isolated from malignant tumors are relevant to human TECs (hTECs) from human epithelial malignant tumors.In the present study, we investigated chromosomal aberration in hTECs freshly isolated from RCCs (spontaneous human tumors) by FISH analysis. To study the mechanism of TEC aneuploidy, we analyzed cell-cell fusion and the relationship between progenitor marker-positive cells and TEC aneuploidy in cross-species tumor models.     

Ultrastructural Characterization of Oligodendroglial-like Cells in Central Nervous System Tumors

Cells with uniform, small-round nucleus and clear cytoplasm (oligodendroglial-like cell, OLC) are commonly observed in central nervous system (CNS) neoplasm of glial and neuronal lineage, such as oligodendroglioma, clear-cell ependymoma, and central neurocytoma. Immunohistochemistry does not always contribute to the characterization of OLC because of (1) loss of antigen expression; (2) lack of specific markers for oligodendrogliomas; and (3) occasional coexpression of neuronal and glial antigens. An ultrastructural analysis associated with an immunohistochemical study of 20 cases of CNS tumors largely constituted by OLCs has been performed. Neurocytomas (12 cases), medullocytomas (2 cases), cerebral neuroblastoma (1 case), and ganglioglioma (1 case) showed OLCs with ultrastructural features of neuronal differentiation (neu-ritic processes, dense-core granules, synaptic structures). Oligodendroglioma (3 cases) OLCs were characterized by mitochondrial-rich cytoplasm, and ependymoma (1 case) OLCs showed microrosettes and scattered cilia. The electron microscopic analysis can provide a more precise diagnosis of these OLC-containing tumors despite their uniform morphological appearance.     

Primitive Cerebral Tumor with Rhabdoid Features: A Case of Phenotypic Rhabdoid Tumor of the Central Nervous System

The rhabdoid tumor (RT) was first described as an aggressive neoplasm of unknown histogenesis affecting the kidneys of infants and young children, but has since been reported in all ages and in many other primary sites, including the central nervous system. It has been shown, however, that the histologic and cytologic features of RT can be mimicked by many other tumors of known histogenesis. For this and other reasons it remains controversial whether cases of putative extrarenal RT represent the same histogenetic entity as RT of the kidney (RTK), another entity or entities, or merely a diverse collection of unrelated tumors sharing a common morphologic phenotype. The present paper describes a lethal primary cerebral tumor in a 26-month-old Hispanic boy that was composed predominantly of cells exhibiting the “classic” rhabdoid phenotype by light microscopy. lmmunocytochemical and ultrastructural studies disclosed features of primitive neuroglial differentiation not seen in RTK. The findings in this case, as well as evidence from other studies, would seem to support the notion that primary RT of the brain may in fact constitute a morphologic and clinicopathologic entity. However, hat entity likely represents a distinctive type of neuroglial neoplasm, more closely related t o other primitive brain tumors than t o RTK.     

Primitive Cerebral Tumor with Rhabdoid Features: A Case of Phenotypic Rhabdoid Tumor of the Central Nervous System

The rhabdoid tumor (RT) was first described as an aggressive neoplasm of unknown histogenesis affecting the kidneys of infants and young children, but has since been reported in all ages and in many other primary sites, including the central nervous system. It has been shown, however, that the histologic and cytologic features of RT can be mimicked by many other tumors of known histogenesis. For this and other reasons it remains controversial whether cases of putative extrarenal RT represent the same histogenetic entity as RT of the kidney (RTK), another entity or entities, or merely a diverse collection of unrelated tumors sharing a common morphologic phenotype. The present paper describes a lethal primary cerebral tumor in a 26-month-old Hispanic boy that was composed predominantly of cells exhibiting the “classic” rhabdoid phenotype by light microscopy. lmmunocytochemical and ultrastructural studies disclosed features of primitive neuroglial differentiation not seen in RTK. The findings in this case, as well as evidence from other studies, would seem to support the notion that primary RT of the brain may in fact constitute a morphologic and clinicopathologic entity. However, hat entity likely represents a distinctive type of neuroglial neoplasm, more closely related t o other primitive brain tumors than t o RTK.     

Rhabdoid tumours of the central nervous system

Summary Three cases of rhabdoid tumour of the central nervous system arising in a supratentorial location are reported. The patients were 18, 14, and 7 years old. All three tumours showed a common morphology. The neoplastic cells were usually globoid with round nuclei and prominent nucleoli and large acidophilic, cytoplasmic inclusions were present in many of them. These inclusions showed strong immunoreactivity for vimentin, weak immunoreactivity for epithelial membrane antigen and focal immunoreactivity for cytokeratins. Ultrastructurally they were made up of whorls of intermediate filaments, 8–10 nm in thickness. Rhabdoid tumours of the central nervous system, whatever the cell of origin, appear to be an independent entity with identifiable histology and aggressive behaviour.     

Dendritic Cells in the Context of Human Tumors: Biology and Experimental Tools

Dendritic cells (DC) are the most potent and versatile antigen-presenting cells (APC) in the immune system. DC have an exceptional ability to comprehend the immune context of a captured antigen based on molecular signals identified from its vicinity. The analyzed information is then conveyed to other immune effector cells. Such capability enables DC to play a pivotal role in mediating either an immunogenic response or immune tolerance towards an acquired antigen. This review summarizes current knowledge on DC in the context of human tumors. It covers the basics of human DC biology, elaborating on the different markers, morphology and function of the different subsets of human DC. Human blood-borne DC are comprised of at least three subsets consisting of one plasmacytoid DC (pDC) and two to three myeloid DC (mDC) subsets. Some tissues have unique DC. Each subset has a different phenotype and function and may induce pro-tumoral or anti-tumoral effects. The review also discusses two methods fundamental to the research of DC on the single-cell level: multicolor flow cytometry (FCM) and image-based cytometry (IC). These methods, along with new genomics and proteomics tools, can provide high-resolution information on specific DC subsets and on immune and tumor cells with which they interact. The different layers of collected biological data may then be integrated using Immune-Cytomics modeling approaches. Such novel integrated approaches may help unravel the complex network of cellular interactions that DC carry out within tumors, and may help harness this complex immunological information into the development of more effective treatments for cancer.