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Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have followed 14 patients with the Zollinger-Ellison syndrome for a median period of 9 years. All patients have suffered from peptic ulcer disease and six of the 14 have had complications such as bleeding or perforated ulcer. Almost half the patients have had diarrhoea as a dominant symptom and 4 patients suffered from multiple endocrine neoplasia. Before 1978, the year when the H2-receptor antagonists were introduced, the majority of the patients were operated with total gastrectomy. After that year there has been no need for gastrectomies, but all but two patients have undergone an explorative laparotomy. We have been able to localize the gastrinoma in 9 of 12 operated patients; in 7 cases it was localized within the gastrinoma triangle. Three of the patients are considered to have been cured after surgery. Eight patients have needed adjuvant acid-reducing medical therapy. Five of these have been failures to high doses of H2-receptor antagonists and have been successfully treated with omeprazole. Five patients have died during the follow-up period and death in two of these cases was related to tumor progression.
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PMID:Long-term follow up of patients with Zollinger-Ellison syndrome (ZES). 257 21

Several possible mechanisms for the initiation and progression of tumors in multiple endocrine neoplasia type 2 (MEN 2) merit consideration. Localization of MEN2A to the pericentromeric area of chromosome 10 indicates the site of the initial mutagenic event but does not explain the tissue specificity observed. The consistency of tissue involvement within families, despite the variability between families, suggests that the tumors result from separate but contiguous tissue-specific genes arranged in a particular linear order. Linkage studies in MEN 2A and 2B families are compatible with this contiguous gene theory. Data suggest that Knudson's two-mutational-event theory is applicable in MEN 2, with cellular hyperplasia resulting from the initial heritable mutation. The second event could be a homozygous allelic mutation, but the lack of consistent loss of heterozygosity of chromosome 10 markers in tumors suggests other mechanisms. Observations in MEN 2 may be explained by the heritable chromosome 10 mutation causing hyperplasia, with the hyperplastic cells being converted to cancer cells by second mutations at any of many possible sites. Tumor progression probably involves subsequent events at other loci. These hypotheses may have important clinical implications.
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PMID:Genetic mechanisms of neoplasia in MEN 2. 257 40

Medullary thyroid carcinoma (MTC) is an important human cancer for the study of molecular abnormalities that underlie initiation of neoplasia and subsequent cellular changes during tumor progression. This tumor can occur in different inherited forms, each mediated by autosomal dominant genetic events. Germline abnormalities on chromosome 10 are linked to at least one type of genetic MTC, multiple endocrine neoplasia type II. Our studies of chromosome 10 in DNA from MTC tumors failed to detect frequent loss of polymorphic DNA markers, suggesting that the genetic mechanisms involved in MTC development may be different from those for other inherited cancers such as retinoblastoma. During tumor progression of MTC, abnormalities develop in expression of the mature phenotype of the endocrine cell from which the tumor arises. In cell culture, chemical modulation or gene insertion can lead to partial correction of these defects in differentiation capacity by activating cellular signaling processes. These studies offer opportunities to dissect the molecular events that regulate endocrine cell differentiation, to determine the precise abnormalities that may underlie the initiation and tumor progression events in MTC and related cancers, and, thereby, to identify new targets for therapeutic intervention.
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PMID:The molecular biology of medullary thyroid carcinoma. A model for cancer development and progression. 265 32

The gene for familial malignant melanoma and its precursor lesion, the dysplastic nevus, has been assigned to a region of the distal short arm of chromosome 1, which is frequently involved in karyotypic abnormalities in melanoma cells. We have examined loci on chromosome 1p for loss-of-constitutional heterozygosity in 35 melanomas and 21 melanoma cell lines to analyze the role of these abnormalities in melanocyte transformation. Loss-of-heterozygosity at loci on chromosome 1p was identified in 15/35 (43%) melanomas and 11/21 (52%) melanoma cell lines. Analysis of multiple metastases derived from the same patient and of melanoma and lymphoblastoid samples from a family with hereditary melanoma showed that the loss-of-heterozygosity at loci on distal 1p is a late event in tumor progression, rather than the second mutation that would occur if melanoma were due to a cellular recessive mechanism. Comparisons with neuroblastoma and multiple endocrine neoplasia (MEN2) suggest that the frequent 1p loss-of-heterozygosity in these malignancies is a common late event of neuroectodermal tumor progression.
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PMID:Loss of alleles from the distal short arm of chromosome 1 occurs late in melanoma tumor progression. 273 11

The advent of the histamine H2-receptor antagonists and the renewed interest in curative surgery in patients with gastrinoma have made the differentiation between benign and malignant tumors of critical importance. An analysis of 65 patients with gastrinoma followed for an average of 93 months revealed two distinct clinical groups: those with and those without hepatic tumors at initial examination or operation. Among the 14 patients with hepatic tumors, 12 had multiple liver metastases from pancreatic or duodenal primary tumors, and 2 had primary hepatic gastrinomas. Ten of the 14 patients (71 percent) died from tumor progression, and the total tumor-related mortality for this group was 79 percent. In contrast, only 1 of 15 patients (7 percent) with tumor in the lymph nodes died from a tumor-related cause (recurrent ulcer hemorrhage), and none died from tumor progression. Only a single patient with lymph node metastases at initial exploration went on to the development of liver metastases, which was found incidentally at autopsy 313 months later. Among 23 patients with either primary tumors only or no tumors found at laparotomy, there was only one tumor-related death and no deaths from tumor spread. Life-table analysis demonstrated a significantly decreased length of survival for patients with liver tumor compared with those without liver involvement. Multiple endocrine adenopathy syndrome was not a significant factor in survival. Serum gastrin levels were likewise nondiscriminatory. Six of 52 patients (12 percent), including three with tumor in the lymph nodes, were apparently cured by excision of all gastrinoma recognized at laparotomy. The cure rate was 23 percent for patients without multiple endocrine adenopathy syndrome or liver metastases. Hepatic metastases is a definitive marker for clinically malignant disease and portends a poor prognosis. Patients with gastrinoma confined to the lymph nodes uncommonly follow a malignant clinical course. Such patients have at least a 20 percent probability of surgical cure if they do not have multiple endocrine adenopathy syndrome.
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PMID:Benign and malignant gastrinoma. 285 72

Aging rats of the Long-Evans strain spontaneously develop diffuse and nodular hyperplasia of the adrenal medulla in association with other abnormalities commonly encountered in human multiple endocrine neoplasia syndromes. The cells which comprise the adrenal nodules resemble those in the parent tumor of the rat PC12 pheochromocytoma cell line in that they show varying degrees of spontaneous or nerve growth factor-induced neurite outgrowth in culture and they contain little or no epinephrine. In addition, cells from at least some of the nodules contain immunoreactive neurotensin and neuropeptide-Y, which are also found in PC12 cells. There are a number of striking resemblances between the cells in adrenal nodules and the small granule-containing cells in the normal rodent adrenal. The findings suggest that spontaneous rat adrenal medullary nodules and PC12 cells might be derived from small granule-containing cells, or that cells within the nodules might regain properties of immature chromaffin cells and acquire characteristics of small granule-containing cells and of PC12 cells in the course of neoplastic progression. They further suggest a possible relationship between proliferative capacity and neurotransmitter phenotype in the adult rat adrenal medulla. By virtue of their sparse epinephrine content and their small granules, the cells in adrenal medullary nodules of Long-Evans rats differ from those in adrenal medullary nodules of humans with multiple endocrine neoplasia syndromes.
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PMID:Spontaneous proliferative lesions of the adrenal medulla in aging Long-Evans rats. Comparison to PC12 cells, small granule-containing cells, and human adrenal medullary hyperplasia. 286 75

It is tempting to speculate that genetic studies of the human APUDomas, particularly those of a hereditary nature, may ultimately provide valuable clues to the molecular basis of malignant transformation in cells of all types, uncover the mechanisms responsible for tumor progression, and perhaps decipher the signals important in the differentiation of normal neural crest-derived tissue. Generally, several strategies have been used in the genetic analysis of these tumors with success. These include (1) cytogenetic examination of recurring chromosomal abnormalities in hopes of pinpointing critical neighboring growth regulatory sequences important in tumor evolution, (2) identification of dominant acting oncogenes in tumor cells, (3) search for recessive inactivated suppressor genes that may regulate cell growth by analyzing tumors for loss of heterozygosity (LOH), and (4) genetic linkage studies of kindreds affected with familial APUDomas to identify and subsequently characterize the predisposition gene using a positional or functional cloning approach. The results of these strategies as they have been employed in the investigation of cutaneous malignant melanoma (CMM), the dysplastic nevus syndrome (DNS), and the multiple endocrine neoplasia (MEN) syndromes are summarized.
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PMID:Molecular genetics of APUDomas. 790 6

The tumors of the MEN 2 syndromes, medullary thyroid carcinoma and pheochromocytoma, undergo defined stages of tumor progression. During these stages, several molecular abnormalities develop. These include abnormalities in growth, differentiation, and biochemistry. Recently, the germ-line abnormality in MEN 2A and familial medullary thyroid carcinoma has been identified in the ret gene. This article discusses possible molecular mechanisms for these abnormalities and attempts to place them in the context of the biology of the normal progenitor cells.
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PMID:Molecular abnormalities in tumors associated with multiple endocrine neoplasia type 2. 791 25

In individuals who carry germline mutations in tumor suppressor genes predisposing them to inherited cancer syndromes, occurrence of somatic mutations in the same genes contributes to tumorigenesis. Germline mutations in the RET proto-oncogene predispose individuals to multiple endocrine neoplasia (MEN) type 2 syndromes. Since these mutations are oncogenic by themselves, somatic mutations in the same gene had been thought unnecessary. Recently, a somatic mutation at codon 918 of RET was reported in medullary thyroid carcinoma (MTC) and C-cell hyperplasia in patients with MEN 2A or familial MTC (FMTC), suggesting its possible contribution to tumorigenesis. We describe here a novel somatic mutation at codon 919 in a patient with FMTC carrying a germline mutation at codon 768 that may also be related to tumor progression.
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PMID:A novel somatic mutation in the RET proto-oncogene in familial medullary thyroid carcinoma with a germline codon 768 mutation. 926 28

The development of cancer is due to the accumulation of multiple somatic mutations, in some cases following germline mutations, which occur in hereditary malignancies such as retinoblastomas or multiple endocrine neoplasia (MEN 2A and B). Genetic alterations or changes in the expression of growth regulatory genes can lead to the initiation of malignant transformation and to eventual tumor progression. Cells that have undergone these cumulative alterations in either the structure or expression of these regulatory genes generally possess a selective growth and/or metastatic advantage over other normal non-transformed cells. Thus, activation of dominantly transforming oncogenes by point mutations, gene amplification, chromosomal translocation or insertional mutagenesis can lead to uncontrolled cellular growth or to a disruption in normal differentiation or apoptosis. Equally contributory to the process of malignant progression is the inactivation of recessive tumor suppressor genes due to point mutations and/or loss of heterozygosity in one allele, which can ultimately lead to a reduction of homozygosity in both alleles. Thyroid tumors in humans represent a particularly suitable multistage model of epithelial tumorigenesis. In fact, even though most thyroid neoplasms originate from a single cell type, i.e. the thyroid follicular cell, they include a broad spectrum of tumors with different phenotypic characteristics and variable biological and clinical behaviour. Multiple degrees of malignancies have been defined: from the benign colloid adenomas through the slowly progressive differentiated papillary and follicular carcinomas to the invariably fatal anaplastic carcinomas, although these histological changes are not necessarily sequential. In this review an effort has been made to summarize and integrate new data published on genetic lesions and altered expression of genes involved in the tumorigenesis of the follicular type of thyroid cancer. We have focused our interest only on gene alterations inducing gain or loss of function, that have been studied in vivo in human thyroid tumor specimens by the use of different techniques, such as PCR mediated DNA analyses, sequencing, mRNA level evaluation and protein expression by immunohistochemical staining.
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PMID:Oncogenes and antioncogenes involved in human thyroid carcinogenesis. 938 9


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