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

Disruption of the physiologic balance between cell proliferation and death is a universal feature of all cancers. In general terms, human B-cell lymphomas can be subdivided into 2 main groups, low- and high-growth fraction lymphomas, according to the mechanisms through which this imbalance is achieved. Most types of low-growth fraction lymphomas are initiated by molecular events resulting in the inhibition of apoptosis, such as translocations affecting BCL2, in follicular lymphoma, or BCL10 and API2/MLT1, in mucosa-associated lymphoid tissue (MALT) lymphomas. This results in cell accumulation as a consequence of prolonged cell survival. In contrast, high-growth fraction lymphomas are characterized by an enhanced proliferative activity, as a result of the deregulation of oncogenes with cell cycle regulatory functions, such as BCL6, in large B-cell lymphoma, or c-myc, in Burkitt lymphoma. Low- and high-growth fraction lymphomas are both able to accumulate other alterations in cell cycle regulation, most frequently involving tumor suppressor genes such as p16(INK4a), p53, and p27(KIP1). As a consequence, these tumors behave as highly aggressive lymphomas. The simultaneous inactivation of several of these regulators confers increased aggressivity and proliferative advantage to tumoral cells. In this review we discuss our current knowledge of the alterations in each of these pathways, with special emphasis on the deregulation of cell cycle progression, in an attempt to integrate the available information within a global model that describes the contribution of these molecular changes to the genesis and progression of B-cell lymphomas.
 ...
PMID:Cell cycle deregulation in B-cell lymphomas. 1239 83

The immunohistochemical analysis of lymphoid neoplasms has led to refined classification schemes based on the profile of antigen expression and correlation with morphological, cytogenetic, molecular, and clinical features. Tissue microarrays (TMAs) are a powerful tool to rapidly characterize the phenotypic profile of a large number of samples. We show that this technique can be readily applied to the study of lymphoma by examining the expression profile of a series of 193 B-cell non-Hodgkin's lymphomas (NHLs) and 29 Hodgkin's lymphomas (HLs) using immunohistochemistry and in situ hybridization (ISH). The NHL cases were studied for the expression of commonly used markers-including CD3, CD5, CD10, CD20, CD23, CD30, CD43, Bcl-2, and cyclin D1 by immunohistochemical staining of TMAs-and these results were compared with whole sections (WS) of the same cases. We found a high degree of correlation between the results achieved with TMAs or WS (86% to 100% of cases). P53 and MIB-1 staining were studied, and the results were similar to that reported in the literature. HL cases were stained for CD20, CD30, CD15 (LeuM1), and latent membrane protein 1 expression, and ISH was performed using probes for EBER-1 and-2 transcripts. The results from HL cases on TMA sections matched exactly with those of WS. We correlated cytogenetic results with immunohistochemical stains and morphology in cases of mantle cell lymphoma [t(11;14)(q13;q32)] and follicular lymphoma [t(14;18)(q32;q24)]. This extensive expression profile of B-cell NHLs and HL tissues discloses the ability of TMAs to rapidly screen a large series of cases and represents the first report of method validation for this technique in the study of lymphoma.
 ...
PMID:Application of tissue microarray technology to the study of non-Hodgkin's and Hodgkin's lymphoma. 1239 66

To clarify the clinicopathologic, immunohistologic, and genotypic features of follicular lymphoma arising from the salivary glands, we examined 20 cases of operatively resected primary salivary gland lymphoma and identified 6 such cases. There were 4 women and 2 men with ages ranging from 38 to 64 years (median 50 years). The tumor arose from the parotid gland in 4 cases and the submandibular gland in the remaining 2. Four patients were stage IE and 2 were stage IIE-1. The median follow-up period was 49 months and all patients were alive and well at the time of going to press. Histologically, 5 patients were follicular lymphoma grade 2, and 1 was grade 3. In all specimens in noninfiltrating salivary gland tissue, there was periductal lymphocytic infiltration near the lymphoma. Moreover, myoepithelial sialoadenitis was noted in 2 lesions. An immunohistochemical study revealed all 6 cases were CD10+, CD79a+, bcl-6+, CD3-, CD5-, CD21-, CD23-, and CyclinD1-. The tumor cells expressed bcl-2 in 3 cases and p53 oncoprotein in 4 cases. Two cases revealed clonal bands with polymerase chain reaction (PCR) assay for the immunoglobulin heavy (IgH) gene. The bcl-2/IgH translocation at the major breakpoint region was detected in 1 case (16%). We found a relatively high incidence of follicular lymphomas (30%) in salivary gland lymphomas. Among the mucosa-associated lymphoid tissue (MALT) system, follicular lymphomas appeared to occur frequently in the salivary glands as well as the duodenum and skin. Moreover, follicular lymphoma arising from the salivary glands appeared to have some of the characteristics of MALT-type lymphoma including indolent prognosis, presence of myoepithelial sialoadenitis, and rarity of the BCL-2 gene rearrangement.
 ...
PMID:Follicular lymphoma of the salivary gland: a clinicopathological and molecular study of six cases. 1257 44

To understand P53 gene change of non-Hodgkin's lymphoma (NHL) and human malignant lymphoma cell lines, the exons 5-7 of 29 patients with NHL and 9 kinds of human malignant lymphoma cell lines were studied by silver staining PCR-SSCP technique. Three cases of P53 gene point mutation was found in 29 cases of NHL. Mutation developed in exon 5 in 2 cases, and in exon 6 in 1 case. They were all diffuse lymphoma. In mutation cases, B-cell lymphoma accounted for 2 cases and the other one was T-cell lymphoma. There was no P53 gene mutation in low-grade follicular lymphoma. Seven strains out of 9 kinds of lymphoma cell lines had P53 gene point mutation. One strain had the mutation in exon 5; 5 strains in exon 6 and 1 strain in exons 5, 6, 7. There was a high mutation rate in lymphoma cell lines and low mutation rate in NHL patients. P53 gene plays an important role in lymphoma cell line establishment, cell regeneration and disease evolution.
 ...
PMID:P53 gene mutations in non-Hodgkin's lymphoma. 1284 Aug 70

Some follicular lymphomas histologically transform into diffuse aggressive lymphomas, the prognosis of which is poor. There are, however, no reliable histological criteria for predicting which cases will later undergo such transformation. In low-grade B-cell lymphomas, follicular dendritic cells form dense mesh-like networks that contain accumulating neoplastic B-cells. These are rare in high-grade lymphomas. We immunohistochemically analyzed CD21-positive follicular dendritic cells in 32 follicular lymphomas, including 3 transformed lymphomas, in addition to immunohistological study using P-glycoprotein, p53, and Ki-67. We found that the mesh-like networks in follicles are more clearly defined in low-grade lymphomas than in high-grade lymphomas (p = 0.015). Neoplastic follicles in 2 transformed lymphomas lost the networks of follicular dendritic cells before transformation despite the existence of morphologically clear follicles. This differed from the non-transformed cases of the same cytological grades. Prognosis was statistically better for patients with low-grade tumor than for those with high-grade tumor (p = 0.026), and there was a trend toward poorer survival among CD21-negative cases (p = 0.186). P-glycoprotein, p53, and Ki-67 expressions did not provide sufficient information to predict the transformation of follicular lymphoma. The presence of CD21-positive follicular dendritic cells in neoplastic follicles might help predict the potential of follicular lymphoma to transform to diffuse large B-cell lymphoma.
 ...
PMID:Disappearance of CD21-positive follicular dendritic cells preceding the transformation of follicular lymphoma: immunohistological study of the transformation using CD21, p53, Ki-67, and P-glycoprotein. 1290 19

Higher grade histological transformation of follicular lymphoma (FL) to more aggressive diffuse large B-cell lymphomas (DLBCL) occurs in 10-60% of the cases. Review of the current knowledge of genetic and molecular alterations associated with the higher grade transformation of FCL suggests that the process that leads to clinically and phenotypically similar end-point can occur by functionally diverse genetic lesions. The most commonly identified genetic alterations associated with the FCL transformation are TP53 gene mutations, inactivation of CDKN2A and CDKN2B genes and deregulation of the C-MYC gene. These lesions affect different aspects of normal cell physiology (apoptosis, cell cycle control, and proliferation) and are potential targets for gene-specific therapies.
 ...
PMID:Higher grade transformation of follicular lymphoma: phenotypic tumor progression associated with diverse genetic lesions. 1295 50

The histological transformation from a follicular lymphoma (FL) to a diffuse large B-cell lymphoma (DLBL) occurs in 22% to 30% of all cases of FL. The aim of this study was to identify specific chromosomal gains/losses associated with transformation of FL to DLBL, in addition to the well-known mechanisms like p53 mutation and protein expression and c-myc translocation and up-regulation. This is the first study to meet 2 important conditions for such a comparison. First, we demonstrate that the FL and the DLBL were clonally related, based on identical immunoglobulin gene rearrangements in 5 of the 6 cases. Second, we used laser microdissection microscopy to isolate only the neoplastic cells from the initial FL samples. The results indicate that no single chromosomal abnormality seems to be responsible for the transformation of FL to DLBL. P53 protein overexpression was found in 4 and c-myc translocation in 3 of the 6 transformed DLBLs, but not in the initial FL samples. Additional chromosomal abnormalities were detected by comparative genomic hybridization in all 6 cases when the DLBL was compared with the FL. In the 5 cases with transformation of grade 1 or 2 FL to DLBL, gains at chromosomes 7 (5 of 5 cases), 10p1 (3 of 5 cases), 12 (3 of 5 cases), and 20p13 (2 of 5 cases) and loss at 9q (4 of 5 cases) were the most frequently found abnormalities. A gain on chromosome 7p, in combination with a loss on 9q, was found in 4 of the 5 DLBL that transformed from FL grade 1 or 2.
 ...
PMID:Identification of chromosomal copy number changes associated with transformation of follicular lymphoma to diffuse large B-cell lymphoma. 1456 88

The bcl-2 gene codes for a protein which functions to inhibit apoptotic cell death, that involves an intrinsic normal cell death program. Bcl-2 overexpression was originally described in a follicular lymphoma, but more recently bcl-2 expression has been observed in a variety of other human neoplasms. Variation in the frequency of apoptosis in hormone-sensitive tissues, such as the endometrium, is known to occur as a result of hormonal changes in both physiological and pathological circumstances. In this study we examined bcl-2 protein expression in a total of 170 samples of endometrial tissues (18 proliferative endometrium, 14 secretory endometrium, 35 adenomatous hyperplasia and 103 carcinomas). The results were compared with p53, pRb and c-erbB-2 proteins expression, estrogen and progesterone receptors status, with the proliferative activity and with clinicopathological features. The expression of bcl-2 protein was lower in the group of carcinomas, when compared with the cases of adenomatous hyperplasia (p < 0.0001), normal proliferative (p < 0.0001) and secretory endometrium (p = 0.07). In normal proliferative endometrium bcl-2 expression was correlated with PCNA (p = 0.026) and in secretory endometrium it was correlated with ER status (p = 0.042). In hyperplasias, bcl-2 was correlated with PCNA (p = 0.019) and the PR (p = 0.007) expression. In carcinomas, decreased bcl-2 expression was associated with increased tumor grade (p = 0.04). A positive relationship between bcl-2 expression and pRb, as well as PCNA score (p = 0.014 and p = 0.001, respectively), was also found. These results indicate that bcl-2 expression may play a role in the inhibition of apoptosis in endometrial carcinoma and its expression seems to be associated with tumor differentiation and cell proliferation.
 ...
PMID:Immunohistochemical study of apoptosis-related Bcl-2 protein and its correlation with proliferation indices (Ki67, PCNA), tumor suppressor genes (p53, pRb), the oncogene c-erbB-2, sex steroid hormone receptors and other clinicopathological features, in normal, hyperplastic and neoplastic endometrium. 1459 11

Aberrant expression of the apoptosis inhibitor bcl-2 provides a survival advantage throughout oncogenesis and can facilitate chemotherapeutic resistance in a variety of human cancers. Follicular lymphoma (FL) for example, is characterized by the chromosomal translocation t(14;18), which results in bcl-2 overexpression and initiates lymphomagenesis. Although FL cells possess ample amounts of bcl-2, they respond remarkably well to standard first-round chemotherapy. However, the vast majority of patients relapses and becomes progressively resistant to therapy. We obtained cell lines derived from chemosensitive and chemoresistant FL patients, that are characterized by the chromosomal translocation t(14;18) and expression of bcl-2, to investigate how chemotherapeutic drugs can circumvent bcl-2 anti-apoptotic function and to identify alterations in those pathways that may facilitate resistance to DNA damaging drugs. In chemosensitive FL cells, we found that DNA damaging drugs promote apoptosis through p53-dependent upregulation of the TRAIL-DR5 receptor, resulting in activation of caspase-8 and downstream executioner caspases, thereby evading bcl-2 mediated suppression of apoptosis. Examination of drug resistant FL cell lines revealed that at least two defects in this pathway can contribute to chemotherapeutic resistance: 1. p53 gene mutations that disable the transcriptional response to DNA damaging drugs, including expression of the TRAIL-DR5 receptor, and 2. transcriptional repression of the cell-death executioner enzyme caspase-3.
 ...
PMID:Activation and suppression of the TRAIL death-receptor pathway in chemotherapy sensitive and resistant follicular lymphoma cells. 1461 23

Impaired apoptosis is now recognized to be central to tumor development. Bcl2, activated by chromosomal translocation in human follicular lymphoma, promotes oncogenesis by inhibiting apoptosis. Bim, a distant proapoptotic relative, is emerging as a major physiologic antagonist of Bcl2. Here, we show that loss of Bim is oncogenic. Bim protein levels were elevated in the apoptosis-prone B lymphoid cells of Emicro-Myc-transgenic mice, and Bim-mutant Emicro-Myc mice had increased numbers of IgM-bearing B cells. Emicro-Myc-expressing B lymphoid cells deficient in Bim were refractory to apoptosis induced in vitro by cytokine deprivation or antigen receptor cross-linking. Thus, Bim is induced by Myc in B cells and mediates apoptosis. Remarkably, inactivation of even a single allele of Bim accelerated Myc-induced development of tumors, particularly acute B cell leukemia. None of the primary tumors from Bim(+/-) Emicro-Myc mice displayed loss of the second allele of Bim. These findings indicate that Bim is a tumor suppressor, at least in B lymphocytes, and is haploinsufficient. Whereas the p19Arf/p53 pathway is frequently mutated in tumors arising in Bim(+/+) Emicro-Myc mice, it was unaffected in most Bim-deficient tumors, indicating that Bim reduction is an effective alternative to loss of p53 function.
 ...
PMID:Bim is a suppressor of Myc-induced mouse B cell leukemia. 1507 75


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>