Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An epidemiologic study of clear cell vaginal adenocarcinoma in young women (15-22 years old) showed an apparent association with maternal ingestion of diethylstilbestrol (DES) during 1st trimester pregnancy. In 1971, a Registry of Clear Cell Adenocarcinoma of the Genital Tract in Young Females was established, and shortly thereafter the Food and Drug Administration warned that DES and chemically related nonsteroidal estrogens were contraindicated during pregnancy. DES-exposed females have a 0.14 to 1.4/1000 risk of developing adenocarcinoma of the cervix/vagina by age 24. Diagnoses of these cancers usually are made in girls between the age of 14 and 23 years with peak incidence at age 19; data further shows that DES is an incomplete carcinogen and that additional factors contribute to its carcinogenesis. About 20% of DES-exposed women will have a deformity of the upper vagina/cervix, and approximately 95% will have abnormal columnar epithelium on the cervix/upper vagina. 75% of patients whose mothers were exposed to DES in utero during the 8th week of gestation or earlier will have vaginal adenosis; 7% will have this finding if the mother's exposure occurred after the 17th week. Recent reports also indicate a high incidence of abnormalities in the uterus/oviducts associated with gross changes in the upper vagina/cervix. Asymptomatic girls who had DES exposure in uteru should have a complete annual pelvic examination at menarche or by age 14 years. Younger girls who develop abnormal vaginal bleeding/discharge should also have a periodic thorough examination and Pap smear, as well as palpation of the entire length of the vagina/cervix. So far, cervical/vaginal adenocarcinoma has been diagnosed at initial examination, with the ratio of vaginal to cervical adenocarcinoma being almost 2:1. There is no standard therapy yet for adenocarcinoma of young women. Treatment is on a case to case basis, and prognosis depends on the stage of the disease when diagnosed.
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PMID:Congenital diethylstilbestrol-associated vaginal/cervical adenosis (DES babies). 15 73

Neoplastic and nonneoplastic lesions in untreated (C57BL/6N x C3H/HeN)F1 (B6C3F1) mice used as controls in carcinogenesis tests were tabulated and evaluated. The most common neoplasms in 2,543 male mice were hepatocellular adenomas and carcinomas. In 2,522 female mice, common tumors were lymphomas, leukemias, pulmonary adenomas and carcinomas, hepatocellular adenomas and carcinomas, and pituitary adenomas. The risk of developing most neoplasms increased with the age of the mouse. Hepatocellular carcinomas metastasized in 12% of the animals with these tumors. Other than lymphomas and leukemias, few other tumors metastasized. Nonneoplastic lesions included cystic hyperplasia of the uterus, nephritis, ovarian and uterine cysts, inflammatory lesions of the lung, mineralization in the brain, and focal hyperplasias in several tissues. The focal hyperplasias in lung and pituitary, adrenal, and thyroid glands were suggestive of the early stages of neoplasia. Comparative aspects of lesions in aging mice and their interpretation in carcinogenesis tests are discussed.
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PMID:Neoplastic and nonneoplastic lesions in aging (C57BL/6N x C3H/HeN)F1 (B6C3F1) mice. 28 39

Reports of complications due to estrogen-progestagen combinations are summarized. Common minor symptoms include nausea, abdominal distress, headache, depression, and weight gain. Some of these are directly due to the pill, but others are not; for instance, depression may result from pyrodoxine deficiency, but psychodynamic factors explain the problem in others. Effects on the reproductive organs include secondary amenorrhea in about 2 of every 1000 women; structural and functional changes of the ovaries, uterus, and cervix; increase in incidence of yeast vulvovaginitis; and inhibition of lactation. Most changes in laboratory values of various constituents of blood and other body fluids reflect changes in hepatic function. Thromboembolic diseases, hypertension, and hypertriglyceridemia are rare but more serious conditions for which the pill may be responsible in some cases. Contribution of the pill to carcinogenesis and fetal abnormalities has not been proven.
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PMID:Clinical complications of oral contraceptives. 109 Jan 18

DNA adduct formation in the liver, pancreas, kidneys and uterus in ethynylestradiol (EE)-induced carcinogenesis and the effect of tamoxifen (TAM) on DNA adduct formation were evaluated in female Wistar JCL rats using the 32P-postlabeling method. Hyperplastic nodules were noted in the liver of all rats 4 months after the first oral administration of 0.075 mg of EE, and hepatocellular carcinoma was detected in 8.1% of rats treated with EE for 12 months. DNA adducts increased in the liver for 4 months, reaching a level of 7.3 adducts/10(7) nucleotides and decreasing thereafter. Formation of DNA adducts was also noted in the pancreas and kidney, but the adduct levels were lower than those in the liver. TAM inhibited estrogen receptors (ER) in liver tissues and completely suppressed the development of hyperplastic nodules or hepatocellular carcinoma but did not affect DNA adduct formation in the liver. In this model, therefore, EE is considered to cause mutations of hepatocytes due to DNA adduct formation without mediation by ER and to induce initiated cells to develop into hepatocellular carcinoma in the presence of ER-mediated hormonal activities.
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PMID:32P-postlabeling analysis of DNA adducts in rats during estrogen-induced hepatocarcinogenesis and effect of tamoxifen on DNA adduct level. 131 83

Chronic administration of tamoxifen to female rats causes hepatocellular carcinomas. We have investigated damage to liver DNA caused by the administration of tamoxifen to female Fischer F344/N rats or C57B1/6 or DBA/2 mice using 32P-postlabelling. Following the administration of tamoxifen for 7 days (45 mg/kg/day) and extraction of hepatic DNA, up to 7 radiolabelled adduct spots could be detected after PEI-cellulose chromatography of the 32P-labelled DNA digests. Tamoxifen caused a time-dependent increase in the level of adduct detected up to a value of at least 1 adduct/10(6) nucleotides after 7 days dosing. A dose response relationship was demonstrated over the range of 5-45 mg/kg/day (0.013-0.12 mmol/kg/day). On cessation of dosing there was a loss of adducts from the liver DNA. These adducts were not detected in DNA from vehicle-dosed controls or in DNA from kidney, lung, spleen, uterus or peripheral lymphocytes. Pyrrolidinotamoxifen caused a similar level of adduct formation as tamoxifen. In contrast, no significant adduct formation could be detected in liver DNA from rats given droloxifene or toremifene. Mice given tamoxifen (45 mg/kg/day for 4 days) showed levels of adducts in the liver which were 30-40% of those present in rats. Exposure of rat hepatocytes to tamoxifen in vitro, resulted in induction of unscheduled DNA synthesis, when preparations from rats which had been pretreated with tamoxifen in vivo were used. No such increase could be detected in hepatocytes from control rats, suggesting tamoxifen may induce enzymes responsible for its own activation. Tamoxifen induced a significant increase in micronucleus formation in a dose dependent manner in cultures of MCL-5 cells, a human cell line that expresses 5 different human cytochrome P450 isoenzymes, as well as epoxide hydrolase.
Carcinogenesis 1992 Dec
PMID:Genotoxic potential of tamoxifen and analogues in female Fischer F344/n rats, DBA/2 and C57BL/6 mice and in human MCL-5 cells. 147 24

Cellular oncogenes such as c-fos, c-jun and c-myc are expressed prior to estrogen-induced growth of normal target tissues such as rodent uterus. Transient increases in the levels of these genes are induced by the administration of estradiol and are followed by DNA replication. In this study, we examined the expression of these three oncogenes in estradiol-induced kidney tumors in Syrian hamsters in order to understand mechanistic aspects of hormonal carcinogenesis. Kidney tumors were induced in all male Syrian hamsters treated chronically with estradiol for 7 or 9 months, whereas neoplasms were not detected in animals treated for 5 months. mRNA levels of fos, myc and jun were elevated 15-, 4- and 6-fold respectively in kidney tumors of estradiol-treated hamsters (9 months) compared with age-matched untreated control kidneys. The expression of all three protooncogenes was also increased in the kidney tissue surrounding tumors, though there was no consistent pattern in the ratios of transcripts in the tumor and kidney tissues. After 7 months of estrogen treatment, kidney tumors also contained elevated amounts of c-fos, c-jun and c-myc transcripts at levels comparable with older tumors. In abdominal metastases of hamster kidney tumors, mRNA levels of fos, myc and jun were elevated 9-, 12- and 3-fold respectively over control levels. In kidneys of hamsters treated with estradiol for 5 months, in which tumors were not yet detected, the expression of protooncogenes was slightly increased. Ratios of c-fos, c-myc and c-jun in estrogen-treated (5 months) over control tissue were 1.4, 1.1 and 1.3 respectively. Overexpression of cellular oncogenes such as c-fos, c-jun and c-myc may have played a role in the induction and growth of kidney tumors by estradiol in hamsters.
Carcinogenesis 1992 Apr
PMID:Elevation of protooncogene messenger RNAs in estrogen-induced kidney tumors in the hamster. 157 13

Calcium valproate is an anticonvulsant agent with pharmacokinetic properties similar to sodium valproate and valproic acid. Potential carcinogenesis of calcium valproate was evaluated in B6C3F1 mice and Wistar rats given 125, 250 and 500 mg/kg in the diet for 104 weeks. Survival in treated rats increased in a dose-related pattern despite a tumorigenic response in females. Adenocarcinomas of the uterus and cervix were increased in treated rats when compared to controls. The incidence of uterine neoplasia was 8, 20, 14 and 32% in the control, 125, 250 and 500 mg/kg groups, respectively. Neoplasia in treated rats were detected against a higher than expected background of adenocarcinomas in concurrent controls, since 8% incidence in controls was substantially above the laboratory historical database value of 0.6%. Tumors varied from epithelial masses confined to the endometrium, to transmural, highly desmoplastic neoplasms that invaded the serosa lining and the peritoneal cavity. These tumors metastasized in treated rats but not in controls. The statistically significant (P less than 0.01) increase in uterine adenocarcinomas found in females given 500 mg/kg of calcium valproate contrasts the absence of this tumor type in a previous rat carcinogenicity bioassay with valproic acid. Subcutaneous fibrosarcomas were significantly increased in valproic acid-treated males, but no uterine tumors were reported in females. It is puzzling that a true carcinogenic potential would be expressed by markedly different target organs as obtained with the acid and calcium salt of this moiety.
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PMID:Calcium valproate-induced uterine adenocarcinomas in Wistar rats. 172 66

Toxicology and carcinogenesis studies of dl-amphetamine sulfate, a drug used in the treatment of weight control, narcolepsy, and behavioral syndromes in children, were performed in F344/N rats and B6C3F1 mice. In these studies, amphetamine was administered for 2 years at doses of 0, 20, or 100 ppm in the feed to groups of 50 animals/dose/sex/species. The average amount of amphetamine consumed per day was estimated to be 1 or 5 mg/kg for low or high dose rats, 4 or 30 mg/kg for low or high dose male mice, and 3 or 19 mg/kg for low or high dose female mice. Survival was similar in dosed and control groups. The most notable effect of long-term treatment with this drug was the reduction of body weight in comparison to controls, and reduction in spontaneous tumors including pheochromocytomas of the adrenal gland in male rats, fibroadenomas of the mammary gland in female rats, adenomas of the anterior pituitary gland in male and female rats and female mice, endometrial stromal polyps of the uterus of female rats, adenomas or carcinomas of the liver in male and female mice, adenomas of the Harderian gland in male and female mice, and adenomas or carcinomas of the lung in male and female mice. Decreases in spontaneous tumors have previously been seen in 2-year rodent studies in groups of animals that have a reduced body weight in comparison to controls, but the spectrum of reduction in spontaneous neoplasms after treatment with amphetamine is broader than has previously been observed.
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PMID:Decreases in spontaneous tumors in rats and mice after treatment with amphetamine. 204 32

The observation that mammary carcinogenesis is inhibited in rats which completed a pregnancy prior to exposure to the chemical carcinogen 7,12-dimethylbenz[a]anthracene (DMBA) led us to determine whether the protective effect of pregnancy could be mimicked by treatment with the placental hormone chorionic gonadotropin (hCG). We also studied the effect of this treatment on mammary gland structure and differentiation, and determined whether hCG exerts toxic or collateral effects on body weight and endocrine organs. The systemic effect of hCG on body wt and endocrine organs and mammary gland was studied in outbred virgin Sprague-Dawley rats which at the age of 50 days started receiving 100 IU hCG i.p. daily for 21 days. The animals were subdivided into nine groups of five animals each; one group was killed on the first day of and the others at 5, 10, 15 and 21 days of injection and 5, 10, 15 and 21 days post injection. The effect of the hormonal treatment on the estrous cycle was determined by studying the vaginal smears taken during and after the injection period. The following parameters were determined: body wt, weight and morphology of pituitary gland, adrenals, ovaries and uterine horns. Mammary glands were processed for histology, autoradiography for determination of DNA labeling index (DNA-LI) and whole mount preparation for morphometric studies. The effect of hCG on mammary carcinogenesis was studied in two groups of virgin rats; group I, which at the age of 50 days started receiving a daily i.p. injection of 100 IU hCG for 21 days; 21 days after the last injection they were given 8 mg DMBA/100 g body wt. Group II animals received DMBA only. hCG treated animals gained weight as a function of age at the same rate as controls. Treatment did not modify the weight of adrenal glands. The weight of ovaries, uterus and pituitary gland were transitorily increased by the 15th day of treatment, but had returned to the same values of controls by the time of DMBA administration. Treatment stimulated mammary gland differentiation, measured as a progressive reduction in number of terminal end buds and increase in the number of alveolar buds and lobules. The DNA-LI was significantly depressed in all terminal structures in the glands of treated animals. In group I animals hCG treatment decreased incidence of adenocarcinomas to 6.15 from 43.8% in group II animals.(ABSTRACT TRUNCATED AT 400 WORDS)
Carcinogenesis 1990 Oct
PMID:Effect of human chorionic gonadotropin on mammary gland differentiation and carcinogenesis. 211 9

Estrogens are associated with several cancers in humans and are known to induce tumors in rodents. In this review a mechanism of carcinogenesis by estrogens is discussed which features the following key events: (1) Steroid estrogens are metabolized by estrogen 2- and 4-hydroxylases to catecholestrogens. Target organs of estrogen-induced carcinogenesis, hamster kidney or mouse uterus, contain high levels of estrogen 4-hydroxylase activity. Since the methylation of 4-hydroxyestradiol by catechol-O-methyltransferase is inhibited by 2-hydroxyestradiol, it is proposed that a build up of 4-hydroxyestrogens precedes estrogen-induced cancer. (2) The catecholestrogen or diethylstilbestrol (DES) are oxidized to semiquinones and quinones by the peroxidatic activity of cytochrome P-450. The quinones are proposed to be (the) reactive intermediates of estrogen metabolism. (3) The quinones may be reduced to catecholestrogens and DES and redox cycling may ensue. Redox cycling of estrogens has been shown to generate free radicals which may react to form the organic hydroperoxides needed as cofactors for oxidation to quinones. (4) The quinone metabolites of catechol estrogens and of DES bind covalently to DNA in vitro whereas DNA binding in vivo has only been examined for DES. When DES is administered to hamsters, the resulting DES-DNA adduct profile in liver, kidney, or other organs closely matches that of DES quinone-DNA adducts in vitro. In vitro, DES-DNA adducts are chemically unstable and are generated in incubations with organic hydroperoxide as cofactor. It is proposed that the instability of adducts and the lower sensitivity of previous assay methods contributed to the reported failures to detect adducts. Steroid estrogen-DNA adducts in vivo are currently under investigation. (5) Tumors are postulated to arise in cells rapidly proliferating due to the growth stimulus provided by the estrogenic activity of the primary estrogen or of hormonally potent metabolites such as 4-hydroxyestradiol. The covalent modification of DNA in these cells is temporary because of the chemical instability of adducts and will result in altered genetic messages in daughter cells, whereas in non-proliferating cells there may be no lasting genetic damage. The sequence of events described above is a plausible mechanism for tumor initiation by estrogens and is partially substantiated by experimental evidence obtained in vitro and/or in vivo.
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PMID:Genotoxic effects of estrogens. 216 Jun 7


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