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)

In early cervical intraepithelial neoplasia (CIN), the Ki67 stratification index 90th percentile (Si90) is a strong predictor of progression. This study was designed to further investigate the mechanisms leading to elevated Ki67 levels in lesions that progress and to try to improve the prognostic accuracy of Ki67-Si90. We studied 90 CIN lesions in which consensus existed regarding the grade between two experienced gynecologic pathologists. All CINs were p16-positive and showed Ki67 cell clusters above the lower third of the epithelium (both features diagnostic for CIN). Ki67 parameters, cell cycle regulators (Rb, p53, Cyclin A, E and D, p16, p21, p27, and telomerase), and cellular differentiation products (involucrin, CK13, CK14) were compared in the basal zone as well as the deeper and upper halves of the epithelium. Fifteen CIN cases (17%) progressed to a higher CIN grade, including 2 of 25 CIN1 (8%) and 13 of 65 CIN2 (20%) (these proportions of progressing CINs are similar to those in a large meta-analysis). Ki67 quantitation effectively predicted CIN progression as 0 of 40 "Ki67 low-risk" and 15 of 50 (30%) "Ki67 high-risk" lesions progressed. CIN progressors showed decreased Rb, CK13, CK14, and involucrin, but increased p21 and p27 expression. Ki67-Si90 and Rb in the deeper half of the epithelium (RbDeep) were the strongest multivariate independent predictors of progression. Ki67-Si90>0.57 was unfavorable, but only if it coexisted with RbDeep <45% (progression risk = 47%). All early CINs with combined Si90>0.57+RbDeep>45% or any Ki67-Si90 value below 0.57 were nonprogressors. In the high-risk progression subgroup (Ki67-Si90>0.57+RbDeep<45%), all cases with combined CK14<50% and CK13<80% (both in the basal cell layer) (4% of all lesions) progressed. We hypothesize that onco-HPV E7 expression reduces Rb, causing increased and upward proliferation (Ki67-Si90>0.57). Increased RbDeep can reduce proliferation, including its upward spread. Combined quantitation of Ki67, Rb, CK13, and CK14 gives accurate information about the progression risk of early CIN lesions.
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PMID:Quantitative molecular parameters to identify low-risk and high-risk early CIN lesions: role of markers of proliferative activity and differentiation and Rb availability. 1508 35

Squamous cell carcinoma (SCC) is the most common form of oral malignancy and is often preceded by premalignant lesions, some of which are more likely to progress to carcinoma than others. In this study, a panel of monoclonal antibodies (AE1/AE3, cytokeratin [CK] 14, Ki-67 and p53) is applied to 10 cases of human oral tissue in each of six categories to establish staining patterns indicative of which lesions are more likely to progress to malignancy. The six tissue categories are normal tissue; abnormal benign lesions; mild, moderate and severe dysplasia; and SCC. A statistical analysis of Ki-67 and p53 immunoexpression is performed. The results showed that AE1/AE3 and CK 14 expression was reduced as a late event in oral carcinogenesis, particularly in poorly differentiated SCC. Expression of Ki-67 and p53 proved to be a weak but statistically significant predictor of malignant progression in oral tissue.
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PMID:Immunocytochemical analysis of AE1/AE3, CK 14, Ki-67 and p53 expression in benign, premalignant and malignant oral tissue to establish putative markers for progression of oral carcinoma. 1546 55

The mechanism by which a single mutant cell clonally expands is usually assumed to involve an additional mutation in a cell cycle regulatory gene. An alternative mechanism for driving clonal expansion is apoptosis, which might create vacant stem cell compartments that can be repopulated by mutant cells. This model predicts that in a mouse with reduced apoptotic capacity (i) more mutated cells will appear initially but (ii) these cells will expand into clones more slowly than in wild-type animals. To test this hypothesis for ultraviolet B (UVB)-induced skin carcinogenesis, we examined UVB-induced p53 mutant clones and tumors in a transgenic (Tg) mouse (K14-Survivin) with skin-specific expression of the apoptosis inhibitor Survivin. To limit the effects of Survivin on apoptosis, without affecting epidermal proliferation or differentiation, we used Survivin expression levels and UVB doses that resulted in a 2-fold reduction in keratinocyte apoptosis. After 5 weeks of chronic UVB irradiation, newly created p53 mutant keratinocyte clones (indicative of initial mutation frequency) were 1.4-fold more frequent in K14-Survivin mice (P = 4 x 10(-6)). As predicted, this effect was reversed for clones growing by clonal expansion, which were rarer in Tg skin by 1.7-fold (P = 0.047). At 10 weeks large expanding Tg clones were rarer by a magnitude approaching the apoptosis differential (approximately 2-fold, P = 4 x 10(-5)). Survivin expression also retarded clonal expansion at later stages of tumor development. By 20 weeks 95% of animals carried tumors (primarily papillomas), which were 1.6-fold rarer in apoptosis-defective Tg mice (P = 0.03). In contrast, the rate of tumors attaining large size (> or =3 mm, P = 0.048) and converting to carcinoma was increased approximately 2-fold in Tg mice. Thus, Survivin-regulated apoptosis appears to suppress two stages that involve new mutations, initiation and malignant conversion, yet drives clonal expansion of existing p53 mutant cells.
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PMID:UVB-induced apoptosis drives clonal expansion during skin tumor development. 1549 93

Columnar cell lesions (CCLs) of the breast are a spectrum of lesions that have posed difficulties to pathologists for many years, prompting discussion concerning their biologic and clinical significance. We present a study of CCL in context with hyperplasia of usual type (HUT) and the more advanced lesions ductal carcinoma in situ (DCIS) and invasive ductal carcinoma. A total of 81 lesions from 18 patients were subjected to a comprehensive morphologic review based upon a modified version of Schnitt's classification system for CCL, immunophenotypic analysis (estrogen receptor [ER], progesterone receptor [PgR], Her2/neu, cytokeratin 5/6 [CK5/6], cytokeratin 14 [CK14], E-cadherin, p53) and for the first time, a whole genome molecular analysis by comparative genomic hybridization. Multiple CCLs from 3 patients were studied in particular detail, with topographic information and/or showing a morphologic spectrum of CCL within individual terminal duct lobular units. CCLs were ER and PgR positive, CK5/6 and CK14 negative, exhibit low numbers of genetic alterations and recurrent 16q loss, features that are similar to those of low grade in situ and invasive carcinoma. The molecular genetic profiles closely reflect the degree of proliferation and atypia in CCL, indicating some of these lesions represent both a morphologic and molecular continuum. In addition, overlapping chromosomal alterations between CCL and more advanced lesions within individual terminal duct lobular units suggest a commonality in molecular evolution. These data further support the hypothesis that CCLs are a nonobligate, intermediary step in the development of some forms of low grade in situ and invasive carcinoma.
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PMID:Columnar cell lesions of the breast: the missing link in breast cancer progression? A morphological and molecular analysis. 1589 40

It has been demonstrated that the human tumor suppressor p53 has an important role in modulating histone modifications after UV light irradiation. In this work we explored if the p53 Drosophila homologue has a similar role. Taking advantage of the existence of polytene chromosomes in the salivary glands of third instar larvae, we analyzed K9 and K14 H3 acetylation patterns in situ after UV irradiation of wild-type and Dmp53 null flies. As in human cells, after UV damage there is an increase in H3 acetylation in wild-type organisms. In Dmp53 mutant flies, this response is significantly affected at the K9 position. These results are similar to those found in human p53 mutant tumor cells with one interesting difference, only the basal H3 acetylation of K14 is reduced in Dmp53 mutant flies, while the basal H3-K9 acetylation is not affected. This work shows, that the presence of Dmp53 is necessary to maintain normal H3-K14 acetylation levels in Drosophila chromatin and that the function of p53 to maintaining histone modifications, is conserved in Drosophila and humans.
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PMID:Role of the p53 homologue from Drosophila melanogaster in the maintenance of histone H3 acetylation and response to UV-light irradiation. 1641 38

The aim of this study was to assess the morphological characteristics and immunohistochemical profile of breast carcinomas with basal and myoepithelial phenotypes to obtain a better understanding of their biological behaviour and nature. One thousand nine hundred and forty-four invasive breast carcinomas were examined, using tissue microarray (TMA) technology and immunohistochemistry, to identify those tumours that showed basal and myoepithelial phenotypes, and their immunophenotype profile was characterized using a variety of markers. In addition, haematoxylin and eosin-stained sections of these tumours were studied for several morphological parameters. The findings were correlated with patient and tumour characteristics and outcome data. Tumours were classified into two groups: (1) tumours with basal phenotype [expressing one or both basal markers (CK5/6 and/or CK14)] and (2) tumours with myoepithelial phenotype (expressing SMA and/or p63). Group 1 was further subdivided into two subgroups: (A) dominant basal pattern (more than 50% of cells positive) and (B) basal characteristics (10-50% of cells positive). Group 1 tumours constituted 18.6% (8.6% and 10% for groups 1A and 1B, respectively) and group 2 constituted 13.7% of the cases. In both groups, the most common histological types were ductal/no specific type, tubular mixed and medullary-like carcinomas; the majority of these tumours were grade 3. There were positive associations with adenoid cystic growth pattern, loss of tubule formation, marked cellular pleomorphism, poorer Nottingham prognostic index, and development of distant metastasis. In addition, associations were found with loss of expression of steroid hormone receptors and FHIT proteins and positive expression of p53 and EGFR. The most common characteristics in group 1 were larger size, high-grade comedo-type necrosis, development of tumour recurrence, and absence of lymph node disease. Group 2 tumours were more common in younger patients and were associated with central acellular zones, basaloid change, and positive E-cadherin protein expression. Group 1 characteristics were associated with both reduced overall survival (OS) [log rank (LR) = 22.5, p < 0.001] and reduced disease-free interval (DFI) (LR = 30.1, p < 0.001), while group 2 characteristics showed an association with OS (LR = 5, p = 0.02) but not with DFI. Multivariate analysis showed that basal, but not myoepithelial, phenotype has an independent value in predicting outcome. Breast cancers with basal and myoepithelial phenotypes are distinct groups of tumours that share some common morphological features and an association with poor prognosis. The basal rather than the myoepithelial phenotype has the strongest relationship with patient outcome.
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PMID:Morphological and immunophenotypic analysis of breast carcinomas with basal and myoepithelial differentiation. 1642 94

The class III histone deactylase (HDAC), SIRT1, has cancer relevance because it regulates lifespan in multiple organisms, down-regulates p53 function through deacetylation, and is linked to polycomb gene silencing in Drosophila. However, it has not been reported to mediate heterochromatin formation or heritable silencing for endogenous mammalian genes. Herein, we show that SIRT1 localizes to promoters of several aberrantly silenced tumor suppressor genes (TSGs) in which 5' CpG islands are densely hypermethylated, but not to these same promoters in cell lines in which the promoters are not hypermethylated and the genes are expressed. Heretofore, only type I and II HDACs, through deactylation of lysines 9 and 14 of histone H3 (H3-K9 and H3-K14, respectively), had been tied to the above TSG silencing. However, inhibition of these enzymes alone fails to re-activate the genes unless DNA methylation is first inhibited. In contrast, inhibition of SIRT1 by pharmacologic, dominant negative, and siRNA (small interfering RNA)-mediated inhibition in breast and colon cancer cells causes increased H4-K16 and H3-K9 acetylation at endogenous promoters and gene re-expression despite full retention of promoter DNA hypermethylation. Furthermore, SIRT1 inhibition affects key phenotypic aspects of cancer cells. We thus have identified a new component of epigenetic TSG silencing that may potentially link some epigenetic changes associated with aging with those found in cancer, and provide new directions for therapeutically targeting these important genes for re-expression.
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PMID:Inhibition of SIRT1 reactivates silenced cancer genes without loss of promoter DNA hypermethylation. 1659 66

Epidermal development requires the transcription factor p63, as p63-/- mice are born dead, without skin. The gene expresses two proteins, one with an amino-terminal transactivation domain (TAp63) and one without (deltaNp63), although their relative contribution to epidermal development is unknown. To address this issue, we reintroduced TAp63alpha and/or deltaNp63alpha under the K5 promoter into p63-/- mice by in vivo genetic complementation. Whereas p63-/- and p63-/-;TA mice showed extremely rare patches of poorly differentiated keratinocytes, p63-/-;deltaN mice showed significant epidermal basal layer formation. Double TAp63alpha/deltaNp63alpha complementation showed greater patches of differentiated skin; at the ultrastructural level, there was clear reformation of a distinct basal membrane and hemidesmosomes. At the molecular level, deltaNp63 regulated expression of genes characteristic of the basal layer (K14), interacting (by Chip, luc assay) with the third p53 consensus site. Conversely, TAp63 transcribed the upper layer's genes (Ets-1, K1, transglutaminases, involucrin). Therefore, the two p63 isoforms appear to play distinct cooperative roles in epidermal formation.
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PMID:Differential roles of p63 isoforms in epidermal development: selective genetic complementation in p63 null mice. 1660 49

The progression of mammalian gametogenesis requires a precise balance between cell-cycle activities and elimination of defective gametogenic cells to ensure the perpetuation of species. Both spermatogonia and oogonia are stem cell populations committed to meiosis with the aim of generating haploid gametes for fertilization. At puberty, mitotically dividing spermatogonial cell cohorts maintain the ability of cell renewal and occupy niches in the seminiferous tubule. In contrast, mitotically dividing oogonial cell cohorts produced in the fetal ovary, are exclusively committed to meiosis and produce primordial follicles housing a primary oocyte surrounded by somatic follicular cells. A consistent physiological event during mammalian gametogenesis is the disposal of spermatogenic cells by apoptosis and ovarian follicles by atresia. Cyclin-dependent kinases (Cdks) and their cyclin partners coordinate the activities of the cell cycle. An additional cell-cycle regulatory component is the centrosome. The centrosome harbors regulatory proteins controlling the normal progression of the cell cycle. Changes in individual centrosome proteins can lead to cell-cycle arrest and a decrease in the genomic protective function of p53 that promotes apoptosis. Disruption of cyclin A1, Cdk2, and Cdk4 expression in transgenic mice results in infertility and gonadal atrophy. Cdk-cyclin complexes interact with regulatory proteins, which may fine-tune the activities of the complex. One of the many regulatory proteins is p12, a 115 amino acid growth suppressor polypeptide designated p12(CDK2AP1), partner of Cdk2 and with binding affinity to DNA polymerase alpha/primase. Overexpression of p12 is associated with testicular and ovarian atrophy without affecting fertility. Ectopic expression of p12 was driven by the keratin 14 promoter. Keratin 14 is the pairing partner of keratin 5 and both keratins are expressed in testis. The efficiency of keratin promoters in driving ectopic gonadal gene expression, the association of gonadal atrophy with the ectopic expression of a Cdk2 regulatory protein and the centrosome, as a reservoir of cell-cycle regulatory proteins, open new experimental opportunities to address still lingering questions concerning cell differentiation and division during mammalian gametogenesis.
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PMID:Cell-cycle regulation and mammalian gametogenesis: a lesson from the unexpected. 1670 69

Low-grade intraductal carcinomas (LG-IDCs) of salivary gland are rare neoplasms that resemble atypical ductal hyperplasia or LG-IDCs of the breast. They have been referred to as "low-grade salivary duct carcinomas" or "low-grade cribriform cystadenocarcinomas." Herein, we describe 3 additional cases of LG-IDCs, 2 were pure intraductal carcinomas, although 1 demonstrated increasing cytologic atypia and progression to an invasive adenosquamous carcinoma. The latter had been present for 7 years before demonstrating clinical and pathologic progression to a widely invasive malignancy. The intraductal component in all cases exhibited a remarkable degree of apocrine differentiation. The tumor cells were positive for AE1:AE3, Cam 5.2, high molecular weight keratin, CK7, CK19, BRST-2, and androgen receptors (ARs). S-100 was positive in 2 cases and negative in 1 case. The intraductal neoplastic cells were surrounded by myoepithelial cells positive for CK14, actins, calponin, high molecular weight keratin, and p63. All the tumors were negative for CK20, estrogen and progesterone receptors, Her2Neu, and p53. Extensive apocrine differentiation, expression of ARs, CK7, and CK19, and progression to a widely invasive carcinoma after a long clinical latency have not been reported in LG-IDCs previously. These tumors share some histopathologic features with salivary duct carcinoma including apocrine differentiation, and expression of ARs and BRST-2. The terms "low-grade salivary duct carcinomas" and "low-grade cribriform cystadenocarcinomas" should be abandoned in favor of LG-IDC of salivary gland, which better reflects their predominantly noninvasive, intraductal nature.
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PMID:Low-grade intraductal carcinoma of salivary gland: report of 3 cases with marked apocrine differentiation. 1686 74


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