Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although human breast tumorigenesis is associated with the accumulation of mutations both in oncogenes and in tumor suppressor genes, the identity of the genetic alterations that are critical in the early stages of the breast tumorigenic process remains obscure. A high frequency (27-41%) of loss of heterozygosity (LOH) occurrence has been shown at the MET locus on chromosome band 7q31 and this specific alteration is associated with poorer survival. Here, we report that restriction fragment length polymorphism (RFLP) analysis on 221 informative (heterozygous) primary breast tumors and 57 informative relapses (13 local recurrences and 44 distant metastases) revealed a similar frequency of 7q31 LOH as tumors progress from primary cancer to relapse, in marked contrast to other changes such as 11p15.5 LOH. This finding suggests that inactivation of a putative tumor suppressor gene located in 7q31 is a very early event in breast tumorigenesis. Our results also show that metastatic potential is an induced phenomenon that occurs at a relatively early stage, rather than a marker of tumor progression.
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PMID:Loss of heterozygosity on 7q31 occurs early during breast tumorigenesis. 753 86

Tumour progression involves a series of sequential steps leading to metastasis. For several of these steps, tumour cells must be equipped with the appropriate adhesive phenotype. Contact with adjacent cells in the primary tumour must be reduced, and invasion and metastasis require adhesive interactions with ECM components. A group of adhesion molecules called integrins is involved in many of these interactions. Integrins are heterodimeric transmembrane molecules that link the cell to the cytoskeleton. They mediate adhesion to ECM components and to other cells. They may be present in an active or inactive conformation, and in addition to adhesive events, they transfer signals into the cell inducing changes in gene expression. Both functions implicate integrins in tumour progression, and their role in cancer has been the subject of many studies over the past 5 years. Several studies of human cutaneous melanoma have demonstrated that the expression of integrins correlates with tumour progression in vivo. Furthermore, integrin expression and function in melanoma cell lines have been found to correlate with invasive or metastatic potential. Finally, evidence from experimental studies in vitro and in vivo shows that integrins have a role in melanoma tumorigenesis, invasion, angiogenesis and metastasis. Integrins might be used as prognostic markers for clinical outcome and they may be useful therapeutic targets in melanoma.
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PMID:Role of integrins as signal transducing cell adhesion molecules in human cutaneous melanoma. 755 62

Since the introduction of standardized chemotherapy protocols of osteosarcoma a lot of new aspects in prognosis and curability of these have best developed. Current subclassification which divided osteosarcoma into a conventional type and eleven important recognizable varieties is one of the reason for this success. Cytological grading also serves as a good indicator for the prognosis and is an important criterion for application of adjuvant chemotherapy. Several structure proteins of the extracellular matrix have gained importance in making the diagnosis of an osteosarcoma. Immunohistochemically and biochemically evaluations could show that different collagenous-proteins can be useful for the differential diagnosis of bone tumors. The integration of molecular pathologic methods into the structural morphologic findings will be helpfull in the identification of mutated structure proteins. Oncogenes and tumor suppressor genes are of major importance for the tumorigenesis of osteosarcoma. The prognostic significance of the inactivation of p53 and RBI gene remains to be elucidated. Resistance to chemotherapy is the major mechanism responsible for the failure of osteosarcoma treatment. The main cause for this failure is multidrug resistance, which is often related to a plasma membrane protein, the P-glycoprotein. Immunohistologic investigations of P-glycoprotein are not sufficient to demonstrate the possible association between overexpression of this protein and tumor progression.
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PMID:Current aspects of the pathology of osteosarcoma. 764 21

Inactivation of the p53 tumor suppressor gene appears to be an important event in the progression of many types of human neoplasms; however its role in rodent experimental tumorigenesis is controversial. Previous studies have shown that a wide array of chemically induced and spontaneous mouse liver tumors lack p53 mutations within the evolutionarily conserved regions of exons 5-8. However, since p53 inactivation in human neoplasms occurs relatively late in tumor progression, it is possible that the mouse liver tumors evaluated previously were not suitably advanced to incur p53 aberrations. In the present study, we examined an end-stage, highly malignant embryonal mouse liver tumor known as the hepatoblastoma (HB) for p53 mutations utilizing the highly sensitive 'cold' single-strand conformation polymorphism (SSCP) technique. In addition, several of the HBs were examined by direct nucleotide sequencing. No aberrations of the p53 gene were detected within exons 5-8 of any of the 16 HBs examined. These results confirm that the p53 gene plays a minimal role in the development or malignant progression of hepatocellular tumors in mice.
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PMID:Lack of p53 point mutations in chemically induced mouse hepatoblastomas: an end-stage, highly malignant hepatocellular tumor. 765 27

The somatic mutation theory of tumorigenesis states that mutations are necessary for tumor development. On the other hand, acquired, clonal chromosomal alterations are occasionally detected in otherwise normal, nonneoplastic cells--for example, loss of sex chromosomes occurs in bone marrow cells and lymphocytes in elderly individuals--and it is therefore evident that not all mutations are by themselves sufficient for neoplasia to occur. Thus, the finding of an acquired, clonal chromosomal abnormality does not constitute proof that a lesion is neoplastic. Trisomy 7 has, as the sole clonal chromosomal aberrations, been reported in a wide variety of epithelial tumor types but also in some mesenchymal and neurogenic neoplasms. It has been suggested to be a primary, i.e., tumor-initiating, abnormality in tumors of the bladder, brain, colon, kidney, lung, ovary, prostate, and thyroid. But data from cytogenetic studies of solid tumors, macroscopically normal tissue in the proximity of solid tumors, and nonneoplastic lesions now question the importance of a solitary +7 as a neoplasia-associated change. Most solid tumors in which trisomy 7 has been found as the sole change in one clone have also displayed other, cytogenetically unrelated, clones with complex karyotypic abnormalities. Such karyotypic differences among coexisting clones could indicate that the neoplasm is polyclonal, that the cytogenetically disparate clones have emerged during tumor progression from one original clone carrying submicroscopic genomic changes only, or that the clone with +7 does not represent the tumor parenchyma. The latter interpretation is supported by the finding of cells with trisomy 7 in macroscopically normal tissue outside tumors of the brain, kidney, and lung.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Trisomy 7 in nonneoplastic cells. 768 21

Colorectal cancer provides a unique model for the study of molecular changes that are associated with tumorigenesis. The cancer evolves as an apparent ordered sequence from a benign to a malignant lesion in histopathological recognizable stages. Since it is relatively easy to isolate tissue representing each of these stages, studies of molecular events associated with tumor progression are feasible. Such studies have shown that multiple changes in gene structure, expression and activity occur during tumorigenesis.
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PMID:Gene structure and expression in colorectal cancer. 769 Jan 79

Specific CD44 variant glycoproteins are overexpressed at particular stages of colorectal tumor progression. Some variants of the CD44 glycoprotein without exon v6 sequences appear at the earliest stage of tumorigenesis, i.e., in early adenomas. Expression of variants containing exon v6 sequences is largely restricted to the advanced stages of tumor development and in addition is more prevalent and intense in metastatic (Dukes C/D) than in nonmetastatic (Dukes A/B) carcinomas. The observation that CD44 variants containing a protein domain of CD44 that confers full metastatic potential to rat carcinoma and sarcoma cell lines is increasingly expressed during colorectal tumor progression indicates that this domain may have an important role in tumor progression and metastasis in humans. Information on v6 expression, which can be obtained by routine immunohistochemistry, may prove of important prognostic value, particularly in carcinomas (Dukes A and B) that have not yet given rise to detectable metastases.
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PMID:Expression of CD44 variant proteins in human colorectal cancer is related to tumor progression. 769 4

Transgenic mice bearing the rat neu proto-oncogene under the transcriptional control of the mouse mammary tumor virus (MMTV) promoter develop focal mammary adenocarcinomas after long latency that are metastatic to the lung in a high percentage of the tumor-bearing animals. Because expression of the neu gene in the mammary epithelium precedes the occurrence of tumors, it appears that another genetic event in addition to neu transgene expression is required for tumorigenesis. We have investigated the expression of PEA3, a new member of the ets oncogene family of transcriptional regulatory factors, in neu-induced mammary tumors to learn whether PEA3 plays a role in tumor progression in this organ. We observed high levels of PEA3 RNA in neu-induced tumors, but little, if any, PEA3 RNA in the surrounding mammary epithelium. Moreover, mammary tumors that had metastasized to the lung also overexpressed the PEA3 gene, whereas normal lung tissue did not. Similar results were obtained after analyses of other transgenic mouse lines bearing metastatic mammary tumors induced by polyomavirus middle T antigen. These findings suggest that enhanced expression of PEA3 may be required to facilitate mammary tumor progression and metastasis.
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PMID:PEA3 is overexpressed in mouse metastatic mammary adenocarcinomas. 769 72

Colorectal tumorigenesis proceeds through an accumulation of specific genetic alterations. Studies of the mechanism by which these genetic changes effect malignant transformation have focused on the deregulation of cell proliferation. However, colorectal epithelial homeostasis is dependent not only on the rate of cell production but also on apoptosis, a genetically programmed process of autonomous cell death. We investigated whether colorectal tumorigenesis involved an altered susceptibility to apoptosis by examining colorectal epithelium from normal mucosa, adenomas from familial adenomatous polyposis, sporadic adenomas, and carcinomas. The transformation of colorectal epithelium to carcinomas was associated with a progressive inhibition of apoptosis. The inhibition of apoptosis in colorectal cancers may contribute to tumor growth, promote neoplastic progression, and confer resistance to cytotoxic anticancer agents.
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PMID:Inhibition of apoptosis during development of colorectal cancer. 772 43

Malignancies of childhood include a well-defined spectrum of hematolymphoid, organ specific (adrenal, kidney, liver), soft tissue, bone, and nervous system (central and peripheral) neoplasms with variable biology. Small round cell neoplasms, a subset of childhood malignancies, are histologically similar but differ markedly in their histogenesis, therapy, and prognosis. Traditionally, clinical information and light microscopy, with the aid of histochemistry and ultrastructural evaluation, establish a diagnosis or at least narrow the differential diagnosis. Additionally, immunohistology, cytogenetics, and molecular studies have become important in diagnosis and in defining phenotype/genotype, patient treatment modalities, and prognosis in specific cases. The 11;22 chromosomal translocation typifies Ewing's sarcoma, primitive neuroectodermal tumor, and Askin's tumor, as does the resultant chimeric transcript, while expression and amplification of N-myc oncogene are predictive of the prognosis in neuroblastoma. Furthermore, studies of genes and gene products are elucidating mechanisms of oncogenesis and tumor progression.
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PMID:Immunohistology, cytogenetics, and molecular studies of small round cell tumors of childhood. A review. 776 71


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