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

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

A major goal of cancer research has been to identify genes that contribute to cancer formation. The similar pathology between zebrafish and human tumors, as well as the past success of large-scale genetic screens in uncovering human disease genes, makes zebrafish an ideal system in which to find such new genes. Here, we show that a zebrafish forward genetic screen uncovered multiple cell proliferation mutants including one mutant, crash&burn (crb), that represents a loss-of-function mutation in bmyb, a transcriptional regulator and member of a putative proto-oncogene family. crb mutant embryos have defects in mitotic progression and spindle formation, and exhibit genome instability. Regulation of cyclin B levels by bmyb appears to be the mechanism of mitotic accumulation in crb. Carcinogenesis studies reveal increased cancer susceptibility in adult crb heterozygotes. Gene-expression signatures associated with loss of bmyb in zebrafish are also correlated with conserved signatures in human tumor samples, and down-regulation of the B-myb signature genes is associated with retention of p53 function. Our findings show that zebrafish screens can uncover cancer pathways, and demonstrate that loss of function of bmyb is associated with cancer.
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PMID:A zebrafish bmyb mutation causes genome instability and increased cancer susceptibility. 1615 Jul 6

Polymorphism at codon 72 of p53 results in either the arginine or proline form of p53, whose functional significance in carcinogenesis is controversial. We have investigated if the expression of these p53 polymorphs is selectively regulated, using mRNA from peripheral blood of healthy Asian (Chinese) and the Caucasian (Polish) arginine/proline (arg/pro) heterozygote subjects. Asians were found to preferentially express the pro allele whereas the Caucasians preferentially express the arg allele. On the contrary, about 75% of the heterozygote Chinese breast cancer patients preferentially expressed the arg allele, which rarely contained any somatic mutations. Moreover, histologically normal tissues from Chinese heterozygote breast cancer patients showed selective expression of the arg allele, in contrast to the preferential expression of the pro allele in heterozygote healthy normal breast tissues. Together, the data suggest that the expression of the different p53 polymorphs is selectively regulated in different ethnic populations, and that the arg allele is activated during cancer development in Asians. Thus, the expression status of the p53 polymorphs, rather than the genotypic status, might be a useful indicator for cancer susceptibility.
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PMID:Evidence for selective expression of the p53 codon 72 polymorphs: implications in cancer development. 1617 38

A null mutation in one copy of the Atp2a2 or ATP2A2 gene, encoding sarco(endo)plasmic reticulum Ca2+-ATPase isoform 2 (SERCA2), leads to squamous cell tumors in mice and to Darier disease in humans, a skin disorder that also involves keratinocytes. Here, we examined the time course and genetic mechanisms of tumor development in the mutant animals. Atp2a2+/- mice overexpressed keratins associated with keratinocyte hyperactivation in normal forestomachs as early as 2 months of age. By the age of 5 to 7 months, 22% of mutants had developed papillomas of the forestomach, and 89% of mutants older than 14 months had developed squamous cell papillomas and/or carcinomas, with a preponderance of the latter. Tumors occurred in regions that had keratinized epithelium and were subjected to repeated mechanical irritation. The genetic mechanism of tumorigenesis did not involve loss of heterozygosity, as tumor cells analyzed by laser capture microdissection contained the wild-type Atp2a2 allele. Furthermore, immunoblot and immunohistochemical analysis showed that tumor keratinocytes expressed the SERCA2 protein. Mutations were not observed in the ras proto-oncogenes; however, expression of wild-type ras was up-regulated, with particularly high levels of K-ras. Loss of the p53 tumor suppressor gene occurred in a single massive tumor, whereas other tumors had increased levels of p53 protein but no mutations in the p53 gene. These findings show that SERCA2 haploinsufficiency predisposes mice to tumor development via a novel mode of cancer susceptibility involving a global change in the tumorigenic potential of keratinized epithelium in Atp2a2+/- mice.
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PMID:Haploinsufficiency of Atp2a2, encoding the sarco(endo)plasmic reticulum Ca2+-ATPase isoform 2 Ca2+ pump, predisposes mice to squamous cell tumors via a novel mode of cancer susceptibility. 1620 33

The tumor suppressor P53 pathway plays a crucial role in preventing carcinogenesis and genetic variations of this pathway may be associated with cancer susceptibility. We tested this hypothesis by examining the contribution of functional polymorphisms in P53 and MDM2 to risk of esophageal squamous cell carcinoma (ESCC). DNA from 758 ESCC patients and 1,420 controls were genotyped for P53 codon 72Arg>Pro and MDM2 309T>G polymorphisms. Odds ratios (OR) and 95% confidence intervals (CI) of ESCC were estimated by logistic regression. We observed an increased risk of ESCC associated with the P53 Pro/Pro (OR, 1.83; 95% CI, 1.43-2.35; P < 0.001) or MDM2 GG (OR, 1.49; 95% CI, 1.16-1.91; P = 0.002) genotype, compared with the P53 Arg/Arg or MDM2 TT genotype, respectively. Interaction between these P53 and MDM2 polymorphisms increased risk of ESCC in a multiplicative manner, with the OR being 3.10 (95% CI, 2.07-4.69) for subjects carrying both P53 Pro/Pro and MDM2 GG genotypes. Significant interactions were observed between these polymorphisms and smoking, with risk being the highest (OR, 5.29; 95% CI, 2.91-9.61) in smokers having both P53 Pro/Pro and MDM2 GG genotypes. The MDM2 GG genotype was also associated with risk of developing poorly differentiated and advanced ESCC compared with the GT or TT genotype (OR for high-grade and stages III-IV versus low-grade and stages I-II = 1.60; 95% CI, 1.00-2.64; P = 0.049). The P53 and MDM2 polymorphisms may be genetic determinants for the development of ESCC.
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PMID:The role of P53 and MDM2 polymorphisms in the risk of esophageal squamous cell carcinoma. 1623 Apr 24

The conserved TP53-binding protein 1 (53BP1) is a central mediator of the DNA damage checkpoint and appears to be one of the sensors of DNA double-strand breaks (DSBs). Improper processing of DSBs can result in loss or rearrangement of genetic information, leading to cell death or tumorigenesis. 53BP1 interacts with both TP53 and ATM, key proteins involved in the monitoring of genomic integrity and regulation of apoptosis. 53BP1 is also required for the formation of BRCA1 foci and the C-terminal part of these two proteins display significant homology. Based on its biological function, the 53BP1 gene is a good candidate for being involved in cancer susceptibility. Consequently, in the current study patients belonging to 126 breast and/or ovarian cancer families were screened for germline mutations in the entire coding region of the 53BP1 gene. A number of sequence variants were found, but none of them appeared to associate with cancer predisposition. To our knowledge this is the first comprehensive screening of 53BP1 mutations in familial breast and ovarian cancer cases.
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PMID:Germline alterations in the 53BP1 gene in breast and ovarian cancer families. 1651 57

BRCA1 is a checkpoint and DNA damage repair gene that secures genome integrity. We have previously shown that mice lacking full-length Brca1 (Brca1(delta11/delta11)) die during embryonic development. Haploid loss of p53 completely rescues embryonic lethality, and adult Brca1(delta11/delta11)p53+/- mice display cancer susceptibility and premature aging. Here, we show that reduced expression and/or the absence of Chk2 allow Brca1(delta11/delta11) mice to escape from embryonic lethality. Compared to Brca1(delta11/delta11)p53+/- mice, lifespan of Brca1(delta11/delta11)Chk2-/- mice was remarkably extended. Analysis of Brca1(delta11/delta11)Chk2-/- mice revealed that p53-dependent apoptosis and growth defect caused by Brca1 deficiency are significantly attenuated in rapidly proliferating organs. However, in later life, Brca1(delta11/delta11)Chk2-/- female mice developed multiple tumors. Furthermore, haploid loss of ATM also rescued Brca1 deficiency-associated embryonic lethality and premature aging. Thus, in response to Brca1 deficiency, the activation of the ATM-Chk2-p53 signaling pathway contributes to the suppression of neoplastic transformation, while leading to compromised organismal homeostasis. Our data highlight how accurate maintenance of genomic integrity is critical for the suppression of both aging and malignancy, and provide a further link between aging and cancer.
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PMID:ATM-Chk2-p53 activation prevents tumorigenesis at an expense of organ homeostasis upon Brca1 deficiency. 1667 55

Li-Fraumeni syndrome (LFS) is an autosomal-dominant condition characterized by early-onset sarcoma, breast cancer and other specific tumour types. In most LFS kindreds germline TP53 mutations have been identified. In general, TP53 germline mutations are not associated with late-onset common cancers. We encountered a large kindred in which a wide spectrum of tumour types occurred, including melanoma, breast, ovarian, colorectal, stomach and renal cell cancer, without clear-cut early ages at onset of disease. An Arg213Gln TP53 germline mutation was detected in 12 out of 15 affected family members whereas testing for other cancer susceptibility genes in selected patients was negative. In vitro testing indicated that the specific TP53 mutation inactivates the protein transcriptionally. Our findings suggest that this TP53 germline mutation is a causative factor in this family and that specific TP53 germline mutations can be associated with relatively late-onset common cancers.
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PMID:Late-onset common cancers in a kindred with an Arg213Gln TP53 germline mutation. 1673 87

A G2/M genetic network simulation is trained with tumor incidence data from knockout experiments. The genetic network is implemented using a neural network; knockout genotypes are simulated by removing nodes in the neural network. Two analyses are used to interpret the resulting network weights. We use a novel approach of fixing the network topology that allows knockout TSG (tumor suppressor gene) data from multiple studies to overlap and indirectly inform one another. The trained simulation is validated by reproducing qualitative mammary cancer susceptibilities of ATM, BRCA1, and p53 TSGs. The work described is valuable because it allows TSG mammary cancer susceptibility to be quantified using genetic network topology and in vivo knockout data.
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PMID:Gene knockout experiments to quantify a G2/M genetic network simulation for mammary cancer susceptibility. 1692 82

Li-Fraumeni syndrome (LFS) is an autosomal-dominant cancer predisposition syndrome of which the majority is caused by TP53 germline mutations and is characterised by different tumour types occurring at relatively young age. Recently, it was shown that a single-nucleotide polymorphism (SNP) in the MDM2 gene, SNP309 (T>G variation), was associated with accelerated tumour formation in LFS patients who carry a TP53 germline mutation. To confirm this finding in different populations, we screened 25 Dutch and 11 Finnish TP53 mutation carriers for the presence of the SNP309 G allele in the MDM2 gene. Additionally, we investigated whether the SNP309 G allele plays a role in 72 Dutch TP53-negative LFS and LFS-related patients. In the TP53 germline mutation carriers, a significant difference was seen in the mean age of tumour onset for the SNP309 G allele group, that is, 29.7 years as compared to the SNP309 homozygous T group 45.5 years (P=0.005). In patients of LFS and LFS-related TP53-negative families, no difference was seen in the mean age of tumour onset. However, this TP53-negative group did show a significantly higher percentage of SNP309 homozygotes (G/G) compared to the general population (P=0.02). In conclusion, TP53 germline mutation carriers who have an SNP309 G allele have an earlier onset of tumour formation. The higher prevalence of MDM2 SNP309 homozygous G/G carriers in the TP53-negative group suggests that this allele contributes to cancer susceptibility in LFS and LFS-related families.
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PMID:The single-nucleotide polymorphism 309 in the MDM2 gene contributes to the Li-Fraumeni syndrome and related phenotypes. 1700 41


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