UMLS:C0027627 - FACTA Search

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Query: UMLS:C0027627 (metastases)
103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CD44 is implicated in the regulation of tumor growth and metastasis but the mechanism by which expression of different CD44 isoforms determines the rate of primary and secondary tumor growth remains unclear. In the present study we use a human melanoma transfected with wild-type and mutant forms of CD44 to determine which functional property of the CD44 molecule is critical in influencing tumor behavior. We show that expression of a wild-type CD44 isoform that binds hyaluronic acid augments the rapidity of tumor formation by melanoma cells in vivo, whereas expression of a CD44 mutant, which does not mediate cell attachment to hyaluronate, fails to do so. The importance of CD44-hyaluronate interaction in tumor development is underscored by the differential inhibitory effect of soluble wild-type and mutant CD44-Ig fusion proteins on melanoma growth in vivo. Whereas local administration of a mutant, nonhyaluronate binding, CD44-Ig fusion protein has no effect on subcutaneous melanoma growth in mice, infusion of wild-type CD44-Ig is shown to block tumor development. Taken together, these observations suggest that the tumor growth promoting property of CD44 is largely dependent on its ability to mediate cell attachment to hyaluronate.
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PMID:Interaction between CD44 and hyaluronate is directly implicated in the regulation of tumor development. 751 17

About one in three people in modern industrialised countries die of the consequences of malignant tumours or are found to carry an unsuspected one at the time of autopsy. Early resection of such lesions and appropriate adjuvant therapy is very effective in curing the disease. There is therefore a strong clinical incentive to find effective methods of early diagnosis, assessment of prognosis and treatment of neoplastic lesions and research on this topic is directed at a numerically significant medical problem. Recently it has been found that many human tumours show severe abnormalities in the expression of the CD44 gene which increase with progression to metastatic malignancy. By alternative splicing mechanisms this gene codes for a family of heavily glycosylated cell surface proteins involved in many important cellular activities. In neoplasia there is gross overexpression of various products of the gene associated with disorderly splicing, which can be detected in clinical samples with the sensitive technique of reverse transcription-polymerase chain reaction (RT-PCR). These disturbances begin early in the neoplastic process and can be detected in very small biopsy samples. It has also been shown that it is possible to achieve non-invasive diagnosis of malignancy by analysis of CD44 expression in exfoliated cells in body fluids and waste products. The potential significance of these observations for early diagnosis of symptomatic cancer and for screening of the population for asymptomatic lesions are readily seen and await further investigation. Separate work in our laboratory has succeeded in DNA-mediated transfer of metastatic capability through two rounds of transfection into non-metastatic tumour cells and a metastasis-associated human DNA fragment has been recovered from the transfectants and sequenced. Using primers designed to anneal to a coding region identified by computer analysis within the novel sequence, it has been shown with RT-PCR that it is heavily expressed in metastatic cancer tissues, but not in corresponding normal ones. This could be of value in assessing the prognosis of patients using small biopsy samples from their primary tumours and the potential of this sequence for such purposes and for possible therapeutic intervention is currently being explored. Recent work in several laboratories has shown that elevated expression of certain other specific growth factor genes, including c-met and EGFR, correlates with metastatic capability. Combined evaluation of such markers in further studies will in time give useful information on the prognosis of individual patients to guide therapeutic decisions and the implications of these recent advances for clinical practice and future research are discussed below.
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PMID:Deranged activity of the CD44 gene and other loci as biomarkers for progression to metastatic malignancy. 751 58

Variant CD44 has recently been shown to serve as a metastasis marker in human breast cancer. Certain variant epitopes on primary tumors predict poor survival probabilities for the patients. In this study, immunohistochemical analysis of 16 uterine cervical carcinomas showed strong expression of several CD44 variant epitopes in all samples. In normal cervical epithelia from 5 patients, expression of these epitopes was restricted to particular cell layers, with expression being strong in basal and spinal cells but absent in superficial cells. Fifteen of 16 cancer samples were stained strongly with an antibody which recognizes one particular CD44 epitope that is encoded by both variant exons v7 and v8. This epitope was not detectable in normal cervical epithelium. CD44-mRNA splicing analysis showed qualitative and quantitative differences between malignant and normal tissues with a much more complex splice pattern and high expression of a large CD44 isoform containing variant exons v3 to v10 (including the v7/v8 transition epitope) in about one-half of the cancer samples. Interestingly, patients with lymph node metastases were in this group only. These differences in CD44 epitope expression and mRNA splicing in cervical carcinoma reveal dynamic changes in CD44 expression during carcinogenesis. Such changes could provide metastatic cells with a selective advantage during the carcinogenic process. Furthermore, the v7/v8 epitope may be suitable for screening early stages of cervical cancer.
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PMID:Surface protein expression and messenger RNA-splicing analysis of CD44 in uterine cervical cancer and normal cervical epithelium. 751 19

Hyaluronan-binding sites were demonstrated on the cell surface of three malignant mesothelioma cell lines derived from human tumors using either [3H]hyaluronan or fluorescein-tagged hyaluronan. No hyaluronan-binding activity was observed on normal human mesothelial cells. The absence of hyaluronan receptors on normal human mesothelial cells was not due to a down-regulation by endogenously synthesized hyaluronan, since no binding sites appeared when the cells were cultured under conditions known to suppress hyaluronan synthesis (in starvation medium containing either hydrocortisone or n-butyrate) or to degrade endogenously synthesized hyaluronan (in the presence of Streptomyces or testicular hyaluronidase). The binding of [3H]hyaluronan on mesothelioma cells could be partially inhibited by prior incubation of the cells with trypsin, indicating that the hyaluronan-binding site is a protein. The binding sites on human malignant mesothelioma cells were shown to be saturable with about 54,000 hyaluronan molecules (M(r) 1.4 x 10(6)) bound per cell with a Kd of 0.3 x 10(-9) M. The binding was specific for hyaluronan inasmuch as a number of other macromolecules gave negligible inhibition of the binding. High molecular weight preparations of hyaluronan inhibited the binding more effectively than low molecular weight preparations; hyaluronan oligosaccharides down to a length of six monosaccharide units showed competing activity. The hyaluronan receptor appeared to be related to CD44 (a cell surface glycoprotein previously suggested to function as a hyaluronan receptor) since Hermes-1 monoclonal antibodies which inhibit the binding of hyaluronan to CD44 blocked a major part of the binding of hyaluronan to the mesothelioma cells. However, there was no strict correlation between the hyaluronan-binding activity on the mesothelioma cell lines tested and the levels of CD44 molecules on their cell surface, suggesting that only a subfraction of the CD44 molecules bound hyaluronan or that other hyaluronan-binding proteins also exist on those cells. The presence of hyaluronan receptors on mesothelioma cells, but not on their normal counterparts, may be of importance for the migration of the transformed cells in hyaluronan-enriched matrices and for their ability to form metastases.
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PMID:Hyaluronan receptors are expressed on human malignant mesothelioma cells but not on normal mesothelial cells. 751 23

CD44, an integral membrane glycoprotein expressed by many cell types, serves as the principal transmembrane hyaluronate receptor and may be a determinant of metastatic and invasive behavior in carcinomas. The expression of CD44 in 23 gastric adenocarcinoma and 12 peptic ulcer disease (PUD) resection specimens and gastric carcinoma cell lines HS746t and KATO III was examined by immunohistochemistry using the murine monoclonal antibody A3D8 on formalin-fixed, paraffin-embedded tissue or cells. Western blot analysis of whole cell lysates of KATO III and HS746t cells showed protein bands at 85 to 90 kd with KATO III cells expressing an additional band at 145 kd. In normal stomach gastric epithelium was negative. In PUD foveolar epithelium was focally positive, but staining did not correlate with the extent of gastritis. In carcinoma cases intensity of staining was progressively stronger comparing intestinal metaplasia with dysplasia with intramucosal carcinoma. Invasive carcinoma was invariably more strongly positive than dysplasia or intramucosal carcinoma. Twelve adenocarcinomas were weakly positive and 11 were strongly positive. The staining intensity of metastases (12 cases) was the same or weaker than the primary tumor. For the 12 patients whose carcinomas were weakly positive, mean length of survival for the six who died was 23.3 months. Five of the 11 patients whose carcinomas strongly expressed CD44 died within the study period with a mean length of survival of 11.0 months. A key consequence of CD44 overexpression in gastric carcinomas may be development of the invasive phenotype and strong expression may indicate a poorer prognosis.
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PMID:Expression of the cell adhesion molecule CD44 in gastric adenocarcinomas. 752 75

CD44 is a cell surface receptor that has been implicated in lymphocyte homing, hematopoiesis, cell migration and possibly also tumor metastasis. In the present study, expression of CD44 variant (CD44v) isoforms was analyzed in 23 lung cancer specimens together with corresponding normal lung tissues by Southern blot analysis coupled with reverse transcription-polymerase chain reaction amplification. We found that CD44v isoforms were expressed in all lung cancer specimens, suggesting a possible role in the establishment of metastases by these highly malignant tumors, but normal tissues were also positive. This is in marked contrast to the previous reports of essentially negligible expression of CD44v isoforms in normal colon and breast, and suggests a physiological function in the lung.
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PMID:Expression of CD44 variant isoforms in normal and neoplastic cells of the lung. 753 Feb 40

CD44 designates a group of closely related cell-surface proteins generated by alternative splicing. We have previously shown that splice variants carrying sequences encoded by exon v6 are preferentially expressed in metastatic animal cancer cell lines and that they confer metastatic behaviour on non-metastatic animal tumour cell lines. In this study we set out to assess the expression of CD44 epitopes specific for variant exon sequences in human breast cancer and their potential for determining prognosis. We used affinity-purified polyclonal sera and four monoclonal antibodies raised against the human homologues of CD44 variant exon sequences to investigate the presence of CD44 on 100 primary invasive breast tumours, 12 local recurrences, 18 lymph node metastases, and normal tissue controls. Whereas normal mammary ductal epithelial cells and cells derived from hyperplastic lesions do not express CD44 variant exons, expression of v3, v5, and v6 epitopes was found in most tumour samples. The DIII (exon v6) epitope was present in 84% of the primary tumours and in 100% of axillary lymph node metastases and local recurrences. The presence of these CD44 epitopes is correlated with poor overall survival. 15 patients with exon-v6-negative tumours had good survival compared with 76 patients with exon-v6-positive tumours (p = 0.005; log rank test). Multivariate analysis showed that the CD44 epitope encoded by exon v6 was a good marker for prognosis independent of progesterone receptor, lymph node status, tumour size, and grade.
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PMID:CD44 variant exon epitopes in primary breast cancer and length of survival. 753 42

The cell-surface receptor for hyaluronic acid, CD44, is expressed by both normal and malignant cells. Numerous CD44 isoforms have recently been identified that are derived by alternative ribonucleic acid splicing. The expression of some CD44 isoforms has been shown to be involved in tumor progression and metastatic spread in a rat carcinoma model and in human carcinomas. In the present study, CD44 isoform expression was evaluated by reverse transcriptase-polymerase chain reaction (PCR) analysis in frozen sections derived from three samples of normal brain tissue and from 40 brain tumors, including samples of glioblastoma multiforme, anaplastic astrocytoma, low-grade astrocytoma, cerebral primitive neuroectodermal tumor, medulloblastoma, metastatic colon carcinoma, and metastatic melanoma. Normal brain tissue adjacent to the tumors was also examined in 14 of 18 glioblastomas. In all normal brain and tumor samples, with the exception of metastases from colon carcinoma, PCR analysis demonstrated one prominent product that corresponded to the CD44H hematopoietic form of CD44. Metastases from colon carcinoma demonstrated two prominent PCR amplification products corresponding to CD44H and CD44R1. These results suggest that CD44H is the predominant isoform of this protein in normal human brain tissue and in human neuroectodermal tumors of varying degrees of malignancy. The ability of CD44H to mediate tumor cell motility and invasiveness (in contrast to CD44R1) suggests that the CD44 alternative splicing pattern of neuroectoderm-derived tumors may enhance their local biological aggressiveness and intracerebral spread. The lack of expression of larger molecular weight CD44 variants by primary brain tumors may also partially explain why these tumors rarely metastasize to distant sites.
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PMID:Alternative RNA splicing of the hyaluronic acid receptor CD44 in the normal human brain and in brain tumors. 753 36

CD44 is the transmembrane adhesion molecule which binds hyaluronate. The gene encoding CD44 is found on chromosome 11p and comprises 20 exons. Differential splicing of the 10 extracellular juxtamembranous exons (v1-10) generates the major isoforms of CD44. The major CD44 isoform found on hematopoetic cells (CD44s) contains none of the variably expressed exons, while the major isoform expressed on epithelial cells [CD44(v8-10)] contains exons v8-10. Metastasis-specific isoforms of CD44 were first documented in a model of rat pancreatic adenocarcinoma [CD44(v4-7), CD44(v6-7)] and subsequently in other cancers. This study is the first characterization of CD44 isoforms in primary and metastatic human pancreatic adenocarcinomas. CD44 isoforms were analyzed in specimens of 15 primary and 6 metastatic pancreatic adenocarcinomas as well as in 6 specimens of control pancreata by two different methods. Radiolabeled reverse transcriptase-PCR coupled with 8% PAGE allowed analysis of the major isoforms of CD44, while Southern blot hybridization with [alpha-32P]dCTP-labeled probes permitted analysis for metastasis-specific CD44 isoforms containing CD44(v6) or CD44(v8-10). No differences in the expression of CD44(v8-10) and CD44s were found among the primary and metastatic pancreatic adenocarcinomas, and control specimens of pancreata. However, a novel CD44(v6) isoform was found in metastatic lesions and may represent the human homologue of the rat pancreatic adenocarcinoma metastasis-associated CD44 isoform.
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PMID:CD44 isoform expression in primary and metastatic pancreatic adenocarcinoma. 753 74

The prerequisite for a curative resection of metastases is their restriction to the key organs, the liver and lungs, in the sense of a limited dissemination. For long-term prognosis, the type of primary tumor as well as the radical resection of lung and liver metastases is essential. To improve the process of surgical indication and therapy of tumors, clear definitions for the terms "tumor recurrence" and "metastases" have been agreed upon. Research and clinical investigation have led to a better understanding of tumor-regulating factors, some of which are briefly described: Metastasis promoting factors include the lack of E-cadherin, which leads to a local penetration of basal membranes by tumor cells; CD44 seems to play an important role in cell-cell and cell-matrix interactions, apparently increasing the metastatic potential of tumors and reducing the long-term survival of patients. High levels of urokinase in primary tumors are also associated with a poorer prognosis, as well as plasminogen inactivator inhibitor PAI II, which plays a crucial role in tumor growth. Positive findings in bone marrow aspirates of patients with different malignancies, stained for cytokeratin 18, either are associated with higher recurrence rates in colon and breast cancer or can be correlated to the prognosis of patients with gastric cancer. Technical aspects of surgery for hepatic, pulmonary and skeletal metastases are presented and discussed with respect to curative and palliative indications.
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PMID:Surgical treatment of tumor metastases: general considerations and results. 753 64

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