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Query: UMLS:C0001430 (adenoma)
 21,222 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bilateral malignant polyadenomas of adrenals seem to be rare. They involve either a double primary adrenal tumour, or a metastasis of a controlateral tumour. In the observation reported here, the evolution is characterized by periods of central stimulation with partial autonomy, and periods of tumoral autonomy with central inertness. Pathological findings consist of coexistence of various histological aspects (atrophy, hyperplasia, benign adenoma, carcinoma) suggesting the successive steps of a very particuliar adrenal carcinogenesis. Such findings allow to discuss the following physiopathological mechanism: a stimulation by ACTH might have resulted initially in a preneoplasic hyperplasia, then in an incompletely autonomous tumour, and finally in an autonomous tumour. Accordingly, from a practical and therapeutic point of view, it would be suitable, after removal of an adrenal tumour, especially of one with demonstrated ACTH-dependance, to suppress totally endogenous ACTH by cortisol or cortisone therapy, in order to reduce the occurence of corticotropin stimulation of possibly remaining malignant adrenal cells.
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PMID:[Partially hormone dependent bilateral malignant polyadenomatous hyperplasia]. 20 15

The effect of reovirus type 3 infection on the pulmonary adenoma response to urethan in strain A mice was examined. Urethan carcinogenesis in this system was suppressed from 30 to 60% when mice were exposed to reovirus either 6 days before, on the same day as, or 14 days after urethan administration. These findings suggested that reovirus infection interfered with the progression of urethan-induced pulmonary adenoma rather than the induction of lung tumors by urethan. When mice received multiple exposures to reovirus, the lung tumor response was enhanced. These findings indicated that reovirus infection in particular and virus infection in general may play an important role in the carcinogenic response to environmental chemicals.
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PMID:Effect of reovirus infection on pulmonary tumor response to urethan in strain A mice. 20 99

Orthoaminoazotoluol was administered to mice for a period of 9 months. The duration of the G2-and S-periods of the mitotic cycle determined by the autoradiographic method, and mitotic duration--by the stathmokinetics technique with the use of colchicine in the intact liver, the cells of the adenoma nodes, and primary hepatomas. The duration of the S-period of the intact hepatocytes and adenoma nodes proved to be equal (13.8 hours, respectively). As to the primary hepatoma cells--it decreased to 12.8 hours. The duration of the G2-period showed no essential change during the carcinogenesis, and was equal to 2.2--2.7 hours. An average mitotic duration in the course of 24 hours was also constant and was approximately equal to 1 hour. A rise in the number of mitoses and PNA-synthesizing cells in the hepatomas occurred as a result of entering in mitosis and the S-period of a greater number of cells, but not as a result to prolongation of the duration of the S-and M-periods of the mitotic cycle.
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PMID:[Duration of the mitotic cyle of mouse liver cells at different stages of carcinogenesis induced by ortho-aminoazotoluene]. 62 83

The flame retardants tris(2,3-dibromopropyl)phosphate, tetrakis(hydroxymethyl)phosphonium chloride, and polyvinyl bromide were tested for carcinogenic activity by skin application 3 times weekly in random-bred female ICR/Ha Swiss mice for 420 to 496 days. Tris(2,3-dibromopropyl)phosphate at two dose levels (30 mg and 10 mg/application) induced benign and malignant tumors of the skin, forestomach, and oral cavity (tongue and gingiva) in a statistically significant number of mice (30/group). A statistically significant incidence of papillary tumors of the lung was observed at both dosages, and the higher dose also resulted in one mouse with a tubular adenoma of the kidney. Tetrakis(hydroxymethyl)phosphonium chloride (2 mg/application, 60 mice) and polyvinyl bromide (0.1 ml latex suspension/application, 30 mice) were inactive. Polyvinyl bromide was also injected s.c. into another group of female ICR/Ha Swiss mice once weekly for 48 weeks, and the mice were observed for a total of 60 weeks. Liposarcomas were induced in 19 of 30 mice, which was ascribed to physical carcinogenesis. Appropriate solvent and no-treatment control groups were included.
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PMID:Mouse skin carcinogenicity tests of the flame retardants tris(2,3-dibromopropyl)phosphate, tetrakis(hydroxymethyl)phosphonium chloride, and polyvinyl bromide. 68 15

The effect of dietary undegraded carrageenan (Viscarin 402) on colon carcinogenesis was studied in female inbred F344 rats. Weanling rats were fed semipurified diets containing 0 or 15% undegraded carrageenan. At 7 weeks of age, all animals except controls were given azoxymethane (AOM) s.c. at a dose rate of 8 mg/kg body weight per week for 10 weeks or methylnitrosourea (MNU) intrarectally at a dose level of 2 mg/rat twice a week for 3 weeks. The AOM groups were autopsied 40 weeks and the MNU groups 30 weeks after the first injection. No tumors were induced in the colon or in other organs of untreated rats fed the control diet. One untreated rat fed the carrageenan diet showed a colon adenoma. The animals fed the carrageenan diet and treated with AOM or MNU had a higher incidence of colorectal tumors (number of rats with colorectal tumors and number of tumors per tumor-bearing rat) than did those fed the control diet and treated similarly. The undegraded carrageenan (Viscarin 402) in the diet had an enhancing effect in colorectal carcinogenesis in rats evoked by AOM or MNU.
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PMID:Effect of dietary undegraded carrageenan on colon carcinogenesis in F344 rats treated with azoxymethane or methylnitrosourea. 71 28

The aetiopathogenesis of adult renal tumors is poorly understood. The specific chromosomal changes detected by the study of tumor karyotypes suggest a cascade of oncogene activation and tumor suppressor gene inactivation in the course of renal carcinogenesis. These cytogenetic studies have isolated two entities: non-papillary carcinomas (clear cell and/or eosinophil carcinomas) and tubulopapillary tumors (cortical adenoma, basophil papillary carcinoma). Specific changes of the short arm of chromosome 3 are observed in 70 to 85% of cases of clear cell carcinomas, while trisomy 17 is detected in 70% of cases of tubulopapillary tumors. Cytogenetics is also able to distinguish low and high grade malignant tubulopapillary carcinomas. Limited data are available at the present time concerning oncocytomas.
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PMID:[Genetic aspects of renal tumors in adults]. 130 17

The loss of HLA antigens by neoplastic cells is considered important for tumor growth and metastasis, since it may allow tumors to escape immune surveillance. We studied the expression of HLA class I and II antigens in the colons of 10 patients with familial adenomatous polyposis (FAP), a condition which leads inevitably to colorectal cancer. Expression of HLA class antigens was studied by immunohistochemistry in (a) adenomas from patients with FAP, (b) histologically normal mucosa distant from the adenomas, and (c) histologically normal colonic mucosa from normal subjects. The expression of HLA class I and II antigens was decreased in histologically normal mucosa from FAP patients compared to normal controls. Adenomas showed a similar but quantitatively more pronounced reduction (or loss) of HLA antigen expression. The reduction of HLA expression in adenomas was comparable to that observed in sporadic colon carcinomas. This generalized suppression of HLA gene expression in the colon of FAP patients, which precedes the onset of overt histological manifestations of neoplasia, may be an important early event in colon carcinogenesis.
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PMID:Loss of colonic HLA antigens in familial adenomatous polyposis. 131 51

In a previous study, using a chemical carcinogen, we converted in vitro a non-tumorigenic cell line derived from a human colorectal diploid adenoma, designated PC/AA, into a tumorigenic cell line which, when inoculated into athymic nude mice, produced progressively growing adenocarcinomas. We now report that continuous in vitro passage of the PC/AA adenoma cell line resulted in its spontaneous transformation to a mucinous carcinoma with a modal karyotype of 51, XY, +i(Iq), +8, +9, +13, +i(13q), -21, +mar. These studies show that a single adenoma can be converted along 2 independent pathways, giving rise to either a mucinous carcinoma or an adenocarcinoma, and provide further experimental evidence for the adenoma-carcinoma sequence. Cytogenetic changes which occur along both pathways to tumorigenicity include abnormalities of chromosome I and multiple copies of chromosome 13. These abnormalities may be important in tumour development and progression in colorectal carcinogenesis.
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PMID:A single human colonic adenoma cell line can be converted in vitro to both a colorectal adenocarcinoma and a mucinous carcinoma. 131 72

We studied the development of liver tumors in male transforming growth factor alpha (TGF-alpha) transgenic mice of the CD1 strain and examined the expression of the transgene by immunohistochemistry and in situ hybridization. Livers of 4-5-week-old transgenic mice contained areas of centribobular hypertrophy with low glucose-6-phosphatase activity. These areas progressively expanded, and hypertrophy and dysplasia became generalized in livers of mice at 10-12 months of age. The expression of the transgene, determined by either immunohistochemistry or in situ hybridization, was uneven in animals that were 10 weeks old or older. The positive hepatocytes formed patches with a predominant centrilobular distribution. We studied a total of 23 liver tumors (7 hepatocellular carcinomas and 16 adenomas) obtained from 11 mice at 13-15 months of age and from one 7-month-old animal which received zinc sulfate to induce the transgene. The carcinomas were well differentiated tumors, without glucose-6-phosphatase or gamma-glutamyltranspeptidase activity, that developed from the dysplastic parenchyma and occasionally within an adenoma. In all carcinomas and in 56% of the adenomas there was overexpression of the transgene in relationship to the surrounding tissue. The majority of the tumors that overexpressed TGF-alpha were alpha-fetoprotein positive, while alpha-fetoprotein staining was not detected in tumors (all adenomas) that did not show excessive transgene expression. We conclude that TGF-alpha functions as a promoter of liver carcinogenesis through its effect as an autocrine inducer of hepatocyte proliferation. Further, the data indicate that TGF-alpha overexpression may favor tumor progression.
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PMID:Development of liver tumors in transforming growth factor alpha transgenic mice. 132 2

DNA extracted from 29 colorectal carcinomas and 40 sporadic adenomas was amplified by the polymerase chain reaction (PCR) and analysed for the presence of K-ras gene mutations at codon 12 using a panel of synthetic oligonucleotide probes specific for normal and mutated sequences. The presence of mutations was correlated with various histopathological and clinical data. Ten carcinomas (34.5%) and 14 sporadic adenomas (35%) showed K-ras mutations at codon 12. In the carcinoma group, no apparent correlation was found between the presence of mutant oncogenes and the degree of histological differentiation, Dukes' staging or the development of distant metastasis. In the adenoma group, the frequency of mutations increased with the size of the adenoma and the severity of the dysplastic changes. This study confirms that ras gene mutations are common and early events in colon carcinogenesis. They appear to give a selective growth advantage to those polyps with mutations which leads to their increase in size and thus possibly prepare the ground for malignant transformation.
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PMID:K-ras gene mutations in adenomas and carcinomas of the colon. 134 Dec 61


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