Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumours derived from the thyroid follicular epithelium represent an informative model for understanding the molecular pathogenesis of multistage tumourigenesis, which is the prevailing theory on cancer development and progression nowadays. The early stages of thyroid tumour development appear to be the consequence of the activation or 'de novo' expression of several proto-oncogenes or growth factor receptors, such as ras, ret, NTRK, met, gsp and the thyrotropin (TSH) receptor. Alterations in the expression pattern of these genes are associated with the development of differentiated neoplasms, ranging from benign toxic adenomas (gsp and TSH receptor), to follicular (ras) and papillary (ret/PTC, NTRK, met) carcinomas. They may all be considered to be early events of thyroid cell transformation and, for some, experimental evidence derived from gene transfer studies supports this hypothesis. Alterations in tumour suppressor genes (p53, Rb) are associated instead with the most aggressive and poorly differentiated forms of thyroid cancer, indicating that, in the thyroid tumourigenic process, they represent late genetic events. Specific environmental factors (iodine deficiency, ionizing radiations) have been shown to play a crucial role in promoting the development of thyroid cancer, influencing both its genotypic and phenotypic features. Interestingly, a high percentage of genetic lesions causing thyroid cancer originate from gene rearrangements and chromosomal translocations (ret/PTC, NTRK, Pax-8/PPARgamma) a finding which, being a rare event in most epithelial tumours, makes the molecular pathogenesis of thyroid cancer unique. The uninterrupted flow of information on the molecular genetics of thyroid nodules and cancer will broaden the correlation between genotype and phenotype and will also provide important information for the development of more accurate preoperative diagnostic tools and more efficient treatment choices for the different forms of thyroid cancer.
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PMID:Molecular pathogenesis of thyroid nodules and cancer. 1128 33

Basal cell carcinoma (BCC) is a subtype of nonmelanoma skin cancer (NMSC), a potentially fatal disease linked to overexposure to the sun during childhood. BCC has been associated with UV-induced mutations of the PTC and p53 tumor suppressor genes, and to polymorphisms in the melanocortin-1 receptor and XPD genes. Mortality rates due to BCC are low, but its increasing incidence and prolonged morbidity means the disease is costly to treat. Early recognition and effective treatment are therefore important, to reduce the incidence of BCC and lighten the economic burden of its management. This paper reviews current treatments for BCC, including excision and curettage, electrodessication, surgery, cryosurgery, radiotherapy, and treatment with 5-fluorouracil and intralesional/perilesional cytokines. It also deals with two new treatment modalities, photodynamic therapy and imiquimod 5% cream, an immune response modifier that effectively resolves BCC lesions.
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PMID:New treatment modalities for basal cell carcinoma. 1207 22

Tumors of thyroid follicular cells provide a very interesting model to understand the development of human cancer. It is becoming apparent that distinct molecular events are associated with specific stages in a multistep tumorigenic process with good genotype/ phenotype correlation. For instance, mutations of the gsp and thyroid-stimulating hormone receptor genes are associated with benign hyperfunctioning thyroid nodules and adenomas while alterations of other specific genes, such as oncogenic tyrosine kinase alterations (RET/PTC, TRK) in papillary carcinoma and the newly discovered PAX8/peroxisome proliferator-activated receptor gamma rearrangement, are distinctive features of cancer. Although activating RAS mutations occur at all stages of thyroid tumorigenesis, evidence is accumulating that they may also play an important role in tumor progression, a role that is well documented for p53. Environmental factors (iodine deficiency, ionizing radiations) have been shown to play a crucial role in promoting the development of thyroid cancer, influencing both its genotypic and phenotypic features. It is possible that the follicular thyroid cell has unique ways to respond to DNA damage. Similarly to leukemia or sarcomas (and unlike most epithelial cancers), numerous specific rearrangements are being discovered in thyroid cancer suggesting preferential activation of DNA repair instead of cell death programs after environmentally induced genetic alterations.
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PMID:Molecular pathobiology of thyroid neoplasms. 1266 46

In the present study we review ENT tumor pathology in childhood. Only the most salient aspects are emphasized and the variety of entities reviewed was restricted. Molecular biology techniques reveal infection by human papilloma virus (types 6 and 11) in 50 % of papillomas, while immunohistochemical techniques are less effective in papilloma virus detection. The myofibroblastic nature of nasal angiofibroma has been demonstrated and its incidence is 25 times more frequent in patients with familial polyposis of the colon. Overexpression of p53 occurs in the initial stages of nasopharyngeal carcinoma, while overexpression of c-myc is correlated with an unfavorable prognosis. Recently, olfactory neuroblastoma has been shown not to express the protein product of the MIC-2 gene (antibody 12E7), thus the hypothesis that it could be a member of the Ewing tumor family (neuroectodermal peripheral tumors) has not been confirmed, although it is a primitive neural tumor. The head and neck rhabdomyosarcoma with the best prognosis is that located in the orbit, and cytogenetic studies have shown chromosomic translocation t(2;13) in 50 % of these childhood tumors when they are of the alveolar-type, while trisomy of chromosome 2 or 20 is more characteristic of the embryonic-type. Currently, any classifying features of ENT lymphomas must be based on the Revised European-American Classification of Lymphoid Neoplasms (REAL). Papillary and medullary carcinomas are the most common histological types of thyroid carcinoma in childhood. Alterations in ret/PTC play a significant role in the pathogenesis of both.
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PMID:[Advances in the diagnosis of ENT tumors in childhood]. 1272 79

Thyroid cancers are a leading cause of death due to endocrine malignancies. RET/PTC (rearranged in transformation/papillary thyroid carcinomas) gene rearrangements are the most frequent genetic alterations identified in papillary thyroid carcinoma. Although the oncogenic potential of RET/PTC is related to intrinsic tyrosine kinase activity, the substrates for this enzyme are yet to be identified. In this report, we show that phosphoinositide-dependent kinase 1 (PDK1), a pivotal serine/threonine kinase in growth factor-signaling pathways, is a target of RET/PTC. RET/PTC and PDK1 colocalize in the cytoplasm. RET/PTC phosphorylates a specific tyrosine (Y9) residue located in the N-terminal region of PDK1. Y9 phosphorylation of PDK1 by RET/PTC requires an intact catalytic kinase domain. The short (iso 9) and long forms (iso 51) of the RET/PTC kinases (RET/PTC1 and RET/PTC3) induce Y9 phosphorylation of PDK1. Moreover, Y9 phosphorylation of PDK1 by RET/PTC does not require phosphatidylinositol 3-kinase or Src activity. RET/PTC-induced phosphorylation of the Y9 residue results in increased PDK1 activity, decrease of cellular p53 levels, and repression of p53-dependent transactivation. In conclusion, RET/PTC-induced tyrosine phosphorylation of PDK1 may be one of the mechanisms by which it acts as an oncogenic tyrosine kinase in thyroid carcinogenesis.
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PMID:RET/PTC (rearranged in transformation/papillary thyroid carcinomas) tyrosine kinase phosphorylates and activates phosphoinositide-dependent kinase 1 (PDK1): an alternative phosphatidylinositol 3-kinase-independent pathway to activate PDK1. 1273 63

The activation of RET proto-oncogene through chromosomal translocation is reported as being unique to papillary thyroid carcinomas. However, the reported prevalence of RET/PTC activation in papillary carcinoma was variable, and the clinical relevance of RET/PTC rearrangements in papillary carcinomas is still controversial. To investigate the roles of RET rearrangement in the carcinogenesis of papillary thyroid carcinoma, we have studied RET activation and p53 overexpression in various thyroid lesions of the Japanese population by immunohistochemical technique. RET activation and p53 overexpression were studied in 40 papillary carcinomas, 6 poorly differentiated carcinomas, 4 undifferentiated carcinomas, 2 medullary carcinomas, 2 follicular carcinomas and 19 follicular adenomas. RET activation was observed in 12 out of 40 papillary carcinomas, while no immunoreactivity of RET was detected in other lesions. P53 overexpression was observed in only 1 of 40 papillary carcinomas, but in 2 poorly differentiated carcinomas and 4 undifferentiated carcinomas. The prevalence of RET/PTC activation in papillary carcinoma among the Japanese population was higher than in previous reports. Immunohistochemical technique is proved to be a useful tool to detect RFT/PTC activation in thyroid tumors. RET rearrangements are restricted to a well-differentiated papillary carcinoma, suggesting that RET/PTC positive papillary carcinomas do not progress to undifferentiated carcinoma.
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PMID:RET/PTC fusion gene rearrangements in Japanese thyroid carcinomas. 1536 67

Cholangiocarcinomas are malignant tumors of the intra- or extrahepatic biliary tract. An increasing incidence of cholangiocarcinomas has been documented. This increase might be only apparent, due to the progress in investigation and changes in tumor codification. The major clinical sign of cholangiocarcinomas is obstructive jaundice, which is persistent and progressive. Biological tumor markers are nonspecific: an increased serum level of carcinoembryonic antigen is relevant when associated with an increased level of CA 19-9 or CA-125. K-ras mutation and aberrant expression of p53 are present in one third of intrahepatic cholangiocarcinomas. The firstline imaging investigation is ultrasonography, which always detects dilatation of the bile ducts, but more rarely the tumor itself. Classically, endoscopic retrograde cholangiopancreatography (ERCP), the "gold standard" investigation in case of obstructive jaundice, has been performed following ultrasonography. The actual recommendations, based on grade B and C evidences, are to start investigations with ultrasonography and to continue with noninvasive methods: MRI/MRCP or spiral CT, whenever a malignant obstructive jaundice is suspected. Invasive cholangiography (ERCP, PTC) should be reserved for tissue diagnosis or therapeutic decompression when cholangitis is present, or for stent insertion in unresectable tumors. If MRI, CT or cholangiography do not exclude resectability, hepatic arteriography and portal vein evaluation should be performed preoperatively. All patients who do not have unequivocal cholangiographic and angiographic signs of unresectability should undergo surgery, in order to benefit of a possible tumor resection. The radical surgical procedures relieve the obstruction and jaundice by resecting the tumor. The palliative (surgical or endoscopic) procedures cure the jaundice, but do not remove the tumor. Prognosis of cholangiocarcinomas is dismal, although five-year survival rates for these tumors have improved due progress in surgery and adjuvant oncological therapy.
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PMID:Cholangiocarcinoma: risk factors, diagnosis and management. 1552 94

Recent molecular studies have provided new insights into thyroid carcinogenesis. In thyroid papillary carcinomas at least three initiating events may occur, which are point mutations in the BRAF and RAS genes and RET/PTC rearrangements. Tumors harboring mutant BRAF and RAS are prone to progression to poorly differentiated and anaplastic carcinoma, but most likely require additional mutations to trigger this process. In thyroid follicular carcinomas, two known initiating events are RAS mutations and PAX8-PPARgamma rearrangements, and RAS predisposes to dedifferentiation of follicular carcinomas. p53 and beta-catenin mutations, found with increasing incidence in poorly differentiated and anaplastic carcinomas but not in well-differentiated tumors, may serve as a direct molecular trigger of tumor dedifferentiation. Additional evidence for progression from a preexisting well-differentiated carcinoma to poorly differentiated and anaplastic carcinoma comes from the studies of loss of heterozygosity and comparative genomic hybridization. Molecular studies, although limited by the lack of uniform histologic criteria for poorly differentiated carcinomas, revealed no genetic mutations or chromosomal abnormalities that are unique for poorly differentiated carcinoma and not present in well-differentiated or anaplastic carcinomas. This suggests that poorly differentiated carcinoma, as a group, represents a distinct step in the evolution from well-differentiated to anaplastic thyroid carcinoma, rather than an entirely separate type of thyroid malignancy.
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PMID:Genetic alterations involved in the transition from well-differentiated to poorly differentiated and anaplastic thyroid carcinomas. 1568 56

Papillary thyroid carcinomas are characterized in 70% of cases by the presence of either a RET/PTC rearrangement, or an activating point mutation of RAS or BRAF genes that induce a constitutive activation of the MAP kinase pathway. Follicular carcinomas are characterized by the presence of a RAS mutation or of a PAX8-PPARgamma rearrangement. Inactivating mutations of the p53 gene are found only in anaplastic thyroid carcinomas.
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PMID:[Oncogenes and thyroid tumors]. 1568 24

Mucosa-associated lymphoid tissue lymphoma of the extrahepatic bile duct has not yet been reported. Much more common than this is secondary involvement of the extrahepatic bile duct in cases of disseminated lymphoma. A 59-year-old man manifesting jaundice was referred to our hospital. PTC revealed an extrahepatic bile duct stenosis from the hilum to the lower part of the choledochus. On the operative specimen, we examined L26/CD20, Bcl-2, UCHL-1/CD45RO, cyclin D1 and p53. Histologically, follicular colonization, centrocyte-like cells and lymphoepithelial lesion was observed. Tumor cells were positive for L26/CD20 and Bcl-2 and were negative for intracytoplasmic immunoglobulins, UCHL-1/CD45RO, cyclin D1 and p53. Pathological diagnosis was mucosa-associated lymphoid tissue lymphoma of the extrahepatic bile duct. The authors present herein the first case of mucosa-associated lymphoid tissue lymphoma of the extrahepatic bile duct. It was very difficult to distinguish from hilar cholangiocarcinoma clinically. Only incomplete stenosis of the bile duct and 18-F fluoro-2-deoxyglucose positron emission tomography (FDG-PET) could suggest this unusual clinical entity.
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PMID:Mucosa-associated lymphoid tissue lymphoma of the extrahepatic bile duct. 1581 35


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