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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms of tumorigenesis of adrenocortical neoplasms have not been elucidated as yet. However, loss of heterozygosity at chromosomal locus 17p has been consistently observed in adrenocortical cancer. p53 is a recessive tumor suppressor gene located on chromosome 17p. Mutations in the p53 gene play an important role in the tumorigenesis of diverse types of human neoplasms including breast and colon cancers. More than 90% of all mutations discovered in such tumors have been detected in 4 hot spot areas that lie between exons 5 and 8. In contrast to wild-type p53, mutant p53 accumulates intracellularly and can be easily detected by immunohistochemistry. We therefore investigated the frequency of p53 mutations in human adrenocortical neoplasms using molecular biology and immunohistochemistry techniques. Five patients with adrenocortical adenomas (5 female; ages 39-72 yr), 11 patients with adrenocortical carcinomas (8 female, 3 male; ages 15-50 yr), and two adrenocortical tumor cell lines were studied. After DNA extraction from frozen tumor tissue or paraffin-embedded material, exons 5 through 8 were amplified using the polymerase chain reaction and directly sequenced by the dideoxy termination method. Immunohistochemistry was performed on paraffin-embedded tumor specimens obtained during adrenalectomy using a monoclonal antibody reacting with both wild-type and mutant p53. Prevalence of mutations was adenomas, 0/5, carcinomas, 3/11, and adrenocortical cell lines, 2/2. Single point mutations were detected in 3 cases (exons 5, 6, and 7, respectively), and rearrangements of exon 7/8 and 8 were found in 2 cases. Immunohistochemistry detected strong nuclear and/or cytoplasmic p53 immunoreactivity in all adrenocortical carcinomas with point mutations of the p53 gene but not in adenomas and carcinomas with the wild-type sequence or with deletion/rearrangement of the p53 gene. We conclude that p53 plays a role in the tumorigenesis of adrenocortical carcinomas but is of less importance to benign adenomas.
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PMID:p53 mutations in human adrenocortical neoplasms: immunohistochemical and molecular studies. 812 58

The Li-Fraumeni syndrome was initially recognized through clinical observations at the bed side, which was followed by epidemiological studies. Children suffering from rhabdomyosarcoma were shown to have two or more of six forms of cancer in their parents, grandparents and other relatives, indicating cancer family syndrome. This syndrome has been shown to involve tumor suppressor gene p53 mutations in the germ-line. The patients in the family most often have a proband with soft tissue sarcoma or osteosarcoma, and relatives with breast cancer, brain tumor, leukemia and adrenocortical cancer. Members of the family also appear to be at risk for developing second independent malignancies during their life span. Recommendations on predictive testing for germ line p53 mutations among cancer-prone individuals have been made by the subcommittees, which were sponsored by National Cancer Institute and the National Center for Human Genome Research.
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PMID:[Li-Fraumeni syndrome]. 853 47

Adrenal cancer is a rare neoplasm; however, up to 1 in 1 500 adrenal incidentalomas may hide a carcinoma, which, if diagnosed late or left untreated, is associated with significant morbidity and mortality. Despite extensive investigation of the molecular mechanisms involved in adrenal carcinogenesis and significant improvements in diagnostic imaging, efforts to cure advanced adrenal cancer remain largely unsuccessful. Thus, the investigation of the genetics of adrenocortical cancer by the candidate or positional cloning gene approach is essential in the development of new therapies for this disease. We propose that adrenocortical tumorigenesis follows a pattern similar to that in other organs: As the pathology of the adrenocortical tumor increases towards malignancy, the genetic changes that are observed also increase. Known genetic associations, like TP53 gene changes, occur during the latest stages of adrenocortical tumorigenesis. Thus, it is essential to study the relatively few genes that are affected at the beginning of this process, at the stages of benign tumorigenesis in the cortex. We have studied primary pigmented adrenocortical disease (PPNAD), a benign, bilateral, adrenocortical hyperplasia, which either in its isolated form or as part of Carney complex (CNC), is inherited in an autosomal dominant manner and, therefore, the gene(s) responsible for this disorder could be identified by positional cloning approaches. Indeed, we have identified two genetic loci harboring genes for PPNAD and/or CNC on chromosomal loci 2p16 and 17q22-24. The chromosome 17 gene, PRKAR1A, was recently cloned and the identification of other responsible genes is currently under way in our, and collaborating laboratories. The present report reviews the genetics of adrenocortical cancer first, followed by what is known today about the genetics of PPNAD and/or CNC.
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PMID:Genetics of adrenocortical tumors: Carney complex. 1135 91

Adrenocortical carcinoma is a rare tumor that carries a very poor prognosis. Despite efforts to develop new therapeutic regimens to treat this disease, surgery remains the mainstay of treatment. Laboratory studies of adrenocortical cancers have revealed a wide variety of signaling pathways that can be altered in these neoplasms. Although ACTH signaling through adenylyl cyclase and protein kinase A is important for normal adrenal cellular physiology, there is evidence to suggest that this pathway may inhibit the growth of adrenocortical tumors, and that inactivation of the ACTH receptor may promote tumor formation. Although multiple signal transduction pathways are essential for normal adrenal growth and hormone secretion, efforts to identify events required for neoplastic transformation have met with limited success. Alterations that have frequently been observed in adrenocortical carcinoma include up-regulation of the IGF-II system, as well as mutations in TP53 and RAS. Current studies aim to elucidate the mechanisms of tumor growth by studying proproliferative signaling pathways, such as those involving Akt/PKB and the mitogen-activated protein kinases (MAPKs). Although studies of single pathways have been helpful in guiding investigations, new tools to study the integration and multiplicity of signaling pathways hold the hope of improved understanding of the signaling pathway alterations in adrenocortical cancer.
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PMID:Signaling pathways in adrenocortical cancer. 1211 79

Recent advances in the molecular genetic of adrenal tumors give new insights in the pathophysiology of these neoplasms in both hereditary and sporadic cases. The practice of genetic counselling in patients with adrenal tumors have been recently changed by the identification and the understanding of new specific hereditary cancer susceptibility syndromes. In the case of sporadic adrenocortical tumors these progress also offer new prognosis predictors. The genetic predisposition to adrenocortical cancer in children has been well established in the Li-Fraumeni and Beckewith-Wiedeman syndromes due to germline p53 mutation located at 17p13 and dysregulation of the imprinted IGF-2 locus at 11p15, respectively. Adrenocortical tumors are also observed in Multiple Endocrine Neoplasia type I syndrome. Cushing's syndrome due to primary pigmented nodular adrenocortical disease have been observed in patients with germline PRKAR1A inactivating mutations. Interestingly allelic loss at 17p13 and 11p15 have been observed in sporadic adrenocortical cancer and somatic PRKAR1A mutations in secreting adrenocortical adenomas. The potential interest of these finding for the diagnosis of these tumors will be discussed. In the case of pheochromocytoma and paraganglioma, the demonstration that three genes encoding three succinate dehydrogenase subunits (SDHD, SDHB, SDHC), belonging to the complex II of the respiratory chain in the mitochondria, are involved in the genetics of familial and especially in apparently sporadic phaeochromocytomas have dramatically modified our practice. Up to date, four diagnosis of familal disease (multiple endocrine neoplasia type II, von Hippel Lindau disease, neurofibromatosis type 1 and hereditary paraganglioma) should be discussed and causative mutations in six different phaechomocytoma susceptibility genes (RET, VHL, NF1, SDHB, SDHD, SDHC) could be identified. In this review, we will perform an update compiling these new clinical, genetic and functional data recently published. We will suggest guidelines for the practice of the phaeochomocytoma genetic testing in the patients and their families, and for an early detection of tumors in the patients or in individuals determined to be at-risk of disease by the presymptomatic genetic testing.
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PMID:New insights in the genetics of adrenocortical tumors, pheochromocytomas and paragangliomas. 1600 32

Adrenal masses can be detected in up to 4% of the population, and are mostly of adrenocortical origin. Adrenocortical tumours (ACTs) may be responsible for excess steroid production and, in the case of adrenocortical cancers, for morbidity or mortality due to tumour growth. Our understanding of the pathogenesis of ACTs is more limited than that for other tumours. However, studies of the genetics of ACTs have led to major advances in this field in the last decade. The identification of germline molecular defects in the hereditary syndrome responsible for ACTs has facilitated progress. Indeed, similar molecular defects have since been identified as somatic alterations in sporadic tumours. The familial diseases concerned are Li-Fraumeni syndrome, which may be due to germline mutation of the tumour-suppressor gene TP53 and Beckwith-Wiedemann syndrome, which is caused by dys-regulation of the imprinted IGF-II locus at 11p15. ACTs also occur in type 1 multiple endocrine neoplasia (MEN 1), which is characterized by a germline mutation of the menin gene. Cushing's syndrome due to primary pigmented nodular adrenocortical disease (PPNAD) has been observed in Carney complex patients presenting inactivating germline PRKAR1A mutations. Interestingly, allelic losses at 17p13 and 11p15 have been demonstrated in sporadic adrenocortical cancer and somatic PRKAR1A mutations have been found in secreting adrenocortical adenomas. More rarely, mutations in Gs protein (gsp) and the gene for ACTH receptor have been observed in ACTs. The genetics of another group of adrenal diseases that can lead to adrenal nodular hyperplasia -- congenital adrenal hyperplasia (CAH) and glucocorticoid-remediable aldosteronism (GRA) -- have also been studied extensively. This review summarizes recent advances in the genetics of ACTs, highlighting both improvements in our understanding of the pathophysiology and the diagnosis of these tumours.
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PMID:Molecular genetics of adrenocortical tumours, from familial to sporadic diseases. 1618 67

The TP53 polymorphism occurs at codon 72 of exon 4 with two alleles encoding either arginine or proline. The association between this common polymorphism and risk of different cancers has been extensive studied, however various reports are controversial. We have analyzed the 72Pro polymorphic variant in patients with adrenocortical tumors to evaluate whether 72G--> C substitution at codon 72 of TP53 gene may be associated with increased risk for malignancy in adrenal cortex in comparison to the control group. DNA extracted from peripheral leucocytes of 46 Polish patients with adrenocortical tumors (17 malignant and 29 benign) and 50 controls was examined by PCR-HD method followed by direct sequencing. TP53 polymorphism in codon 72 was found in 47% of ACC cases, in 28% of patients with adenomas and in 24% of controls. The genotype Arg/Arg, Arg/Pro and Pro/Pro distribution was respectively 53%/35%/12% for cancers, 72%/28%/0% for benign tumors and 76%/24%/0% for controls. High frequency of 72Pro allele in patients with carcinoma (29%) in comparison to the benign tumors (14%) and controls (12%) was statistically analyzed. We found that 72Pro variant of TP53 gene was associated with a significantly increased risk of ACC (OR = 3.05; 95% CI = 1.17-7.91, p=0.03). Our results suggest that the TP53 codon 72 polymorphism could be associated with susceptibility for adrenocortical cancer in the examined Polish patients.
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PMID:The TP53 codon 72 polymorphism and predisposition to adrenocortical cancer in Polish patients. 1678 24

Endogenous Cushing syndrome (CS) is caused by excess adrenal glucocorticoid secretion that is adrenocorticotropin (ACTH)-dependent or independent; ACTH-independent adrenocortical causes of CS account for up to 20% of CS in adults, and 15% in children over age 7 years. In younger children, ACTH-independent CS may account for as many as half of the CS cases. In both adults and children, adrenocortical lesions causing CS include the common, isolated and sporadic, solitary cortisol-producing adenoma, the rare adrenocortical cancer, and a spectrum of recently recognized, bilateral hyperplasias (bilateral adrenocortical hyperplasias, BAHs): micronodular adrenal disease and its pigmented variant, primary pigmented nodular adrenocortical disease are mostly genetic processes. Macronodular BAHs, ACTH-independent macronodular hyperplasia or massive macronodular adrenocortical disease are less frequently genetic and almost never present in children (except in McCune-Albright syndrome); they present often with atypical CS in middle-aged or elderly adults. The majority of benign adrenocortical tumors associated with CS are associated with defects of the cAMP signaling pathway, whereas adrenal cancer is linked to aberrant expression of growth factors and germline or somatic mutations of tumor suppressor genes such as TP53. Adrenalectomy is the preferred mode of treatment for all adrenocortical causes of CS.
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PMID:Cushing syndrome caused by adrenocortical tumors and hyperplasias (corticotropin- independent Cushing syndrome). 1849 37

Mitotane, 1,1-dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane (o,p'-DDD) is an agent with adrenotoxic effect, which is able to block cortisol synthesis. This drug and radiotherapy are used also in adrenal cancer treatment even if their biological action in this neoplasia remains unknown. We investigated the effects of o,p'-DDD and ionizing radiations (IR) on cell growth inhibition and cell cycle perturbation in H295R and SW13 adrenocortical cancer cells. Both cell lines were irradiated at a 6 Gy dose and were treated with o,p'-DDD 10(-5) M separately and with IR/o,p'-DDD in combination. This combination treatment induced an irreversible inhibition of cell growth in both adrenocortical cancer cells. Cell cycle analysis showed that IR alone and IR/o,p'-DDD in combination induced the cell accumulation in the G2 phase. At 120 h after IR, the cells were able to recover the IR-induced G2 block while cells treated with IR/o,p'-DDD were still arrested in G2 phase. In order to study the molecular mechanism involved in the G2 irreversible arrest, we have considered the H295R cell line showing the highest inhibition of cell proliferation associated with a noteworthy G2 arrest. In these cells, cyclin B1 and Cdk2 proteins were examined by western blot and Cdk2 kinase activity measured by assay kit. The H295R cells treated with IR/o,p'-DDD shared an increase in cyclin B1 amount as the coimmunoprecipitation of Cdc2-cyclin B1 complex. The kinase activity also shows an increase in the treated cells with combination therapy. Moreover, in these cells, sequence analysis of p53 revealed a large deletion of exons 8 and 9. The same irreversible block on G2 phase, induced by IR/o,p'-DDD treatment, happened in H295R cells with restored wild-type p53 suggesting that this mechanism is not mediated by p53 pathway.
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PMID:Mitotane increases the radiotherapy inhibitory effect and induces G2-arrest in combined treatment on both H295R and SW13 adrenocortical cell lines. 1850 9

The study of the clonality of adrenocortical tumours (ACTs) has shown that adrenocortical cancers (ACCs) are of monoclonal origin. Numerous chromosomal alterations have been observed in ACCs, and they are much more frequent than in adrenocortical adenomas. Progress in the genetics of familial syndromes associated with ACTs helped to identify significant somatic molecular alterations in sporadic adult ACCs. Somatic mutations of the tumour suppressor gene TP53 are observed in a third of ACCs. Interestingly, allelic losses (LOH) at the TP53 locus (17p13) are very frequent, observed in more than 85% of ACCs. The insulin-like growth factor II (IGF-II) locus (11p15) is imprinted. IGF-II is over-expressed in 90% of ACCs. Transcriptome studies have identified an IGF-II cluster of genes significantly over-expressed in ACCs. Transcriptome analysis suggests also that the Wnt/beta-catenin signalling pathway is activated in ACT. About a third of ACCs harbours somatic activating mutations of the beta-catenin gene. This recent progress in the molecular genetics of ACC has led to the development of new molecular markers for the diagnosis of malignancy; these might also help to identify prognostic markers of ACC and may ultimately lead to novel therapeutic approaches.
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PMID:Pathogenesis of adrenocortical cancer. 1950 Jul 68


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