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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adenocarcinoma of the pancreas is presumed to arise from ductal cell precursors. This brief article questions the definitions on which this assumption is based and suggests possible ways to answer the question since for future studies on the etiology of this cancer it is imperative to study the appropriate cell of origin. Possible approaches for future work on pancreatic carcinogenesis utilizing cell and organ culture systems are discussed.
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PMID:Prospectives for cell and organ culture systems in the study of pancreatic carcinoma. 109 31

The effect of ulcers induced by iodoacetamine on the development of gastric tumors by N-methyl-N'-nitro-N-nitrosoguanidine was studied in male Wistar rats. The ulcerative lesions induced by iodoacetamide were confined symmetrically to the fundic region along the limiting ridge in the stomach and the pyloric region was unaffected. Animals treated with iodoacetamide and N-methyl-N'-nitro-N-nitrosoguanidine produced a high incidence of tumors including adenocarcinoma in the fundic region. The incidence of tumors in the pyloric region in the control group was 80% but there were no tumors in the fundic region. The tumors in the fundic region were most frequently found in the same areas that ulcers had previously been induced. These findings suggest that ulceration and regeneration of the mucosa are important factors in gastric carcinogenesis induced in rats by N-methyl-N'-nitro-N-nitrosoguanidine.
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PMID:Effect of fundic ulcers induced by iodoacetamide on development of gastric tumors in rats treated with N-methyl-N'-nitro-N-nitrosoguanidine. 126 57

Thirty-two cases (20.13%) of primary lung cancer from 159 coal miner autopsies of Beijing coal mining area are reported in this study. The ratio of peripheral type to central type of lung cancer is 1.9:1; among them the adenocarcinoma is the most frequent (56.25%). Pathological examination shows that the diffuse interstitial type is the most common lung cancer. The occurrence of adenocarcinoma and the degree of lung fibrosis is related. The average number of ferruginous bodies is 190.2 +/- 8.06 in adenocarcinoma, 165.4 +/- 2.60 in squamous carcinoma, the difference is statistically significant (P < 0.05). The amount of trace elements-Fe, Al, Al/Si and Zn/Cu in lung with cancer is less than that without cancer. This article also discusses the relationship between coal mine pneumoconiosis with lung cancer of the formation of ferruginous bodies in the lung tissue of coal miner autopsies, which resembles the lung cancer combined with asbestosis. We also discussed the carcinogenesis of trace element in lung.
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PMID:[Study on the incidence of coal mine pneumoconiosis and lung cancer in Beijing coal mining district]. 129 8

Five month-old female rats were given a mixture of Sr-90 and Cs-137 in drinking water in the dose of 0.1 and 0.2 microCi/day per animal over 12 months. Some animals received 12 monthly courses of a synthetic immunomodulating dipeptide--thymogen in the dose of 5 micrograms/animal for 5 consecutive days. Radionuclide-treated rats showed higher occurrence of tumors on the whole and of breast adenocarcinoma, in particular. Thymogen was shown to inhibit Sr-90- and Cs-137-induced radiation carcinogenesis, namely, a decrease in the total tumor and cancer occurrence was observed. The animals receiving thymogen alone showed longer life span, slower rate of aging and lower overall tumor and cancer occurrence. In this study, the ability of a synthetic peptide immunomodulator--thymogen to inhibit spontaneous and radionuclide-induced carcinogenesis in female rats was first established.
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PMID:[The effect of the synthetic immunomodulator thymogen on radiation-induced carcinogenesis in rats]. 130 Jul 40

The expression of Ha-ras and fes oncogenes was investigated with the immunohistochemical method in formalin-fixed, paraffin-embedded tissue specimens of 147 lung carcinomas. Positive immunoperoxidase reactions for Ha-ras p21 were found in 80.5% of the adenocarcinomas, 39.5% of the squamous cell carcinomas, 21.4% of the large cell carcinomas, and 15.4% of the small cell carcinomas; those for fes P85 were found in 51.2% of the adenocarcinomas, 26.3% of the squamous cell carcinomas, 35.7% of the large cell carcinomas, and 15.4% of the small cell carcinomas. Both Ha-ras p21 and fes P85 were expressed most frequently and most strongly in adenocarcinoma. In addition, adenocarcinoma showed significantly higher incidence of concomitant expression of Ha-ras p21 and fes P85 as compared with other histologic types of lung cancer. Thus, the authors suggest that the cooperative effects of Ha-ras and fes oncogenes are especially important in the carcinogenesis of adenocarcinoma. In adenocarcinoma, the incidence and grade of Ha-ras p21 expression increased with the degree of histologic differentiation, suggesting that Ha-ras oncogene might be related to cellular differentiation. Papillary adenocarcinoma showed more frequent Ha-ras p21 expression in comparison with acinar adenocarcinoma. In well- or moderately differentiated adenocarcinoma, the incidence and grade of Ha-ras p21 immunoreactivity in the cases with poor prognosis were significantly higher than in those with good prognosis if other major prognostic factors were equivalent in the two groups. The authors propose that the expression of Ha-ras p21 may be one of the useful prognostic factors in such carcinomas.
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PMID:Clinical and histopathologic evaluation of the expression of Ha-ras and fes oncogene products in lung cancer. 131 Aug 87

Endocrine-paracrine (APUD, neuroendocrine) cells are located in the prostatic ductal and acinar epithelium. These cells are of the open and closed type and have dendritic processes. There is a wide range of secretory granule morphology presumably indicating a variety of different cell "types." Secretory immunoreactive peptides include serotonin, calcitonin (and related peptides), somatostatin, bombesin-like, thyroid-stimulating hormone-like (beta chain), and alpha-glycoprotein chain-like. These cells may function by endocrine, paracrine, neurocrine, and lumencrine mechanisms and play an important regulatory role both during growth and differentiation of the prostate as well as in the secretory process of the mature gland. Neuroendocrine differentiation in prostatic carcinoma is a frequent occurrence and manifests itself in several forms, including (1) small cell carcinoma, (2) carcinoid and carcinoid-like tumors, and (3) conventional adenocarcinoma with focal neuroendocrine differentiation. This latter pattern is the most common, and there is evidence that all or nearly all prostatic adenocarcinomas show at least some focal neuroendocrine differentiation. A review of the world's literature on this topic is included. Neuroendocrine differentiation generally portends a poorer prognosis but may also correlate directly with the grade. There is some evidence to suggest that neoplastic cells with neuroendocrine differentiation are resistant to hormonal therapy. Eutopic and ectopic hormone production may allow screening for prostatic carcinoma and/or monitoring for recurrence of prostatic carcinomas. Finally, the more basic implications of endocrine-paracrine cells and neuroendocrine differentiation are speculated on in reference to prostatic carcinogenesis and autocrine/paracrine tumor growth factor activity.
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PMID:Neuroendocrine differentiation in human prostatic carcinoma. 131 90

Adenomatous polyposis coli (APC) is a genetic disorder transmitted as an autosomal dominant trait. This syndrome is characterized by the development of numerous polyps during the first 20-30 years of life and classified into two phenotypes according to the number of polyps: the profuse and sparse types. If left untreated, most or all affected individuals are at a high risk of developing adenocarcinoma by as early as 40 years of age. Therefore, comparison of APC adenocarcinomas with non-polyposis colorectal carcinomas (NPCC) was thought to be useful for understanding genetically determined carcinogenesis. I investigated gene alterations in specimens obtained from 53 APC patients, of which 16 represented the profuse type and the others the sparse type, and from 15 NPCC patients. The results are summarized as follows: 1) K-ras gene mutations were detected more frequently in the profuse-type adenomas (43%) than in the sparse ones (14%) (p less than 0.05). 2) Loss of heterozygosity on the long arm of chromosome 5(5q), 18(18q) and the short arm of chromosome 17(17p) in the profuse-type adenomas was observed more frequently (22%) than in the sparse ones (7.3%) (p less than 0.05). 3) No significant differences were observed between APC adenocarcinomas and NPCCs regarding the allelic deletions on 5q, 17p and 18q in these tumors. 4) The alteration of the DCC gene, which is known to be involved in the formation of NPCC, was frequently detected in the APC adenocarcinomas, suggesting that similar genetic events are involved in the oncogenesis of adenocarcinomas from APC and NPCC.
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PMID:[Genetic analysis of adenomatous polyposis coli: analysis of alterations of oncogenes and tumor suppressor genes in colorectal tumors]. 131 36

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

Fifty cervical adenocarcinomas and 50 squamous cell carcinomas from age-matched patients were examined for human papillomavirus (HPV) types 16 and 18. The polymerase chain reaction was used to examine formalin-fixed, paraffin-embedded carcinoma tissues for 120 and 113 bp sequences, respectively, of the highly conserved E6/E7 regions of the viral genomes. HPV type 16 was detected more often in squamous cell carcinomas than in adenocarcinomas (60% vs 18%, P less than 0.001). Conversely, HPV type 18 was detected significantly more often in adenocarcinoma tissues (52% vs 12% in squamous cell carcinomas, P less than 0.001). These differences may reflect the fact that different virus receptors exist in cervical cells with different morphologic potential, or they may indicate that the specific HPV infection actually plays a role in directing carcinogenesis.
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PMID:Human papillomavirus types 16 and 18 in adenocarcinoma of the uterine cervix. 132 72

Neoplastic transformation occurs in the intrahepatic biliary tree in hepatolithiasis. The present study aimed to clarify the neoplastic processes by correlating the histological features of the bile duct lesions with counts of interphase argyrophilic nucleolar organizer regions (AgNORs), which reflect cell proliferative activity. We studied 55 cases of hepatolithiasis and 25 normal autopsy livers. The biliary epithelial lesions in hepatolithiasis were divisible into hyperplasia, dysplasia and neoplasia. These lesions were found in bile ducts containing calculi. All cases of hepatolithiasis showed a varied degree of hyperplasia. Additionally, eight cases showed dysplasia, five non-invasive intraductal adenocarcinoma and 10 invasive adenocarcinoma. Cases of non-invasive and invasive carcinoma frequently harboured areas of dysplasia, and areas of dysplasia and non-invasive carcinoma, respectively. The mean and standard deviation of the number of interphase AgNORs in the normal and abnormal biliary epithelium showed a step-wise increase in the following order: normal (1.32 +/- 0.36), hyperplasia (1.52 +/- 0.37), dysplasia (2.28 +/- 0.56), non-invasive carcinoma (3.23 +/- 1.00), and invasive carcinoma (3.72 +/- 0.77). These histological and cell kinetic observations suggest that, in hepatolithiasis, carcinogenesis in bile duct epithelial cells progresses in a multi-step manner, through hyperplasia, dysplasia, non-invasive adenocarcinoma and invasive adenocarcinoma.
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PMID:Histological features and interphase nucleolar organizer regions in hyperplastic, dysplastic and neoplastic epithelium of intrahepatic bile ducts in hepatolithiasis. 132 14


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