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

Infiltrating lobular carcinoma (ILC) and infiltrating ductal carcinoma (IDC) are similar in many respects and their histologic features occasionally overlap. Despite the many similarities, some clinical follow-up data and the patterns of metastasis suggest that ILC and IDC are biologically distinct. Unfortunately, most breast cancer research has focused almost exclusively on the ductal subtype or has not stressed the biologic or molecular genetic distinctions between breast carcinoma subtypes. Several reports have suggested the possibility that ILCs and IDCs differ with respect to expression of antigens involved in proliferation and cell cycle regulation. Therefore, we undertook an immunohistochemical evaluation of cell cycle related antigens in ILCs, including histologic variants thought to represent aggressive neoplasms, and IDCs matched for histologic grade (Modified Bloom-Richardson Grade I). We believe that different antigen expression profiles could elucidate the biological distinctiveness of breast carcinoma subtypes and possibly provide diagnostically relevant information. We studied the expression of the following antigens in 28 archived, formalin-fixed ILCs and 34 well-differentiated IDCs: estrogen receptor (ER), progesterone receptor (PR), Her 2-neu, mib-1, cyclin D1, p27, p53, mdm-2 and bcl-2. 94% of ILCs and 100% of IDCs expressed ER; 75% of ILCs and 76% of IDCs expressed PR; 4% of ILCs and 13% of IDCs expressed c cerb B-2; ILCs and IDCs both expressed mib-1 in approximately 10% of lesional cells; 82% of ILCs and 54% of IDCs expressed cyclin D1; 90% of ILCs and 83% IDCs expressed p27 strongly; 4% of ILCs and 4% of IDCs expressed p53, 25% of ILCs and 33% of IDCs expressed mdm-2; 96% of ILCs and 100% of IDCs expressed bcl-2. None of the apparent differences were statistically significant. The ILC variants demonstrated immunophenotypes that were essentially similar to ILCs of the usual type. We conclude that ILCs and well-differentiated IDCs show similar proliferation and cell cycle control antigen profiles. Despite their unusual histologic features, most ILC variants appear to maintain a characteristic ILC immunophenotype.
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PMID:A comparison of cell cycle markers in well-differentiated lobular and ductal carcinomas. 1094 2

No reliable pathologic criteria have been identified that predict clinical behavior in adrenal and extra-adrenal pheochromocytomas (PHEOs). Reliable prognostic markers for the prediction of clinical outcome are needed to assign optimal treatment for potentially malignant tumors. In this report, we evaluated several molecular markers (topoisomerase II alpha, E-cadherin, HER-2/neu, and retinoblastoma (RB) gene protein) that have not been previously studied in PHEOs. Paraffin-embedded, formalin-fixed tissue blocks from 50 cases of PHEO (30 benign and 20 malignant, 31 adrenal and 19 extra-adrenal) were obtained from University of Utah Health Sciences Center, Salt Lake City, and the Medical College of Wisconsin, Milwaukee. Gross (tumor size, weight, local extension, cyst formation, hemorrhage, necrosis), microscopic (pleomorphism, hyaline globules, intranuclear inclusion, mitotic count, capsular and vascular invasion, ganglionic/neuronal differentiation), and immunohistochemical features (topoisomerase II alpha, p53, MIB-1, E-cadherin, RB, and HER-2/neu) were studied. With the exception of vascular invasion (P = 0.025), there were no unequivocal gross or microscopic characteristics that distinguished benign from malignant lesions (P approximately = 0.11-0.71). Topoisomerase III and MIB-1 indices in malignant lesions were significantly higher than those observed in benign lesions (P = 0.012 and 0.019). Differences in p53 expression were not statistically significant (P = 0.082). Loss in RB protein product expression was significantly more common in malignant lesions (P = 0.001), E-cadherin loss and HER-2/-neu overexpression were not observed in any of the benign or malignant lesions. We studied the immunohistochemical expression of topoisomerase II alpha, MIB-1, p53, RB gene protein product, E-cadherin, and HER-2/neu in a series of adrenal and extra-adrenal PHEOs. Overexpression of topoisomerase II alpha and MIB-1 and loss of RB protein product were more common in malignant lesions, whereas p53, E-cadherin, and HER-2/neu do not seem to have diagnostic utility in the prediction of biologic behavior in these neoplasms.
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PMID:Prognostic value of immunohistochemical expression of topoisomerase alpha II, MIB-1, p53, E-cadherin, retinoblastoma gene protein product, and HER-2/neu in adrenal and extra-adrenal pheochromocytomas. 1112 18

The lack of tumor models that can reliably predict for response to anticancer agents remains a major deficiency in the field of experimental cancer therapy. Although heterotransplants of certain human solid tumors can be successfully grown in nude mice, they have never been appropriately explored for prediction of in vivo chemosensitivity to anticancer agents. We determined the tumor response rate and studied the influence of several biological and molecular tumor parameters on the in vivo sensitivity to paclitaxel in a series of heterotransplanted human non-small cell lung cancer (NSCLC) tumors. One hundred consecutive resected NSCLC tumors were heterotransplanted s.c. in nude mice. The in vivo sensitivity to i.v. paclitaxel (60 mg/kg every 3 weeks) was studied in 34 successfully grown heterotransplants. Treatment started when the tumors reached a size of 5 mm in diameter, and strict standard clinical criteria (>50% shrinkage in tumor weight or cross-sectional surface) were used to define tumor response. Baseline multidrug resistance protein (MRP), Her-2/neu, and epidermal growth factor receptor (EGFR) expression, and pre- and posttherapy bax and bcl-2 expression were determined by Western blot analysis. p53 status was determined by sequencing. The overall take rate was 46% (95% confidence interval, 36-56%) and was significantly higher (P < 0.05) for squamous carcinoma tumors (75%) than for adenocarcinoma tumors (30%) and bronchoalveolar tumors (23%). The heterotransplants were morphologically very similar to the original tumors. The response rate to paclitaxel was 21% (95% confidence interval, 9-38%). Baseline tumor parameters associated with response were no Her-2/neu expression (none of the responding tumors expressed Her-2/neu versus 48% of the nonresponding tumors, P = 0.05) and baseline bcl-2 expression (all responding tumors expressed bcl-2 versus only 43% of the nonresponding tumors, P = 0.02). There was a trend toward a higher response rate in bax-positive tumors, and MRP- and EGFR-negative tumors, but it was not statistically significant. The response was independent of baseline p53 status and baseline mitotic index. Responding tumors had a higher bax/bcl-2 ratio 24 h after therapy, but the difference was only marginally significant (2.8 for responding tumors versus 1.1 for nonresponding tumors, P = 0.07). The extent of mitotic arrest at 24 h after therapy was not associated with response. Human NSCLC heterotransplants are morphologically identical to the original tumors and have a response rate to paclitaxel that is equivalent to that reported in Phase II studies in patients with advanced NSCLC treated with single-agent paclitaxel. NSCLC heterotransplants deserve to be explored to evaluate new agents for lung cancer and to predict clinical response on an individual basis in selected groups of patients.
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PMID:Response and determinants of sensitivity to paclitaxel in human non-small cell lung cancer tumors heterotransplanted in nude mice. 1115 54

We have investigated primary ductal carcinomas in situ (DCIS) of the breast and their local recurrences after breast-conserving therapy (BCT) for histological characteristics and marker expression. Patients who were randomized in the EORTC trial 10853 (wide local excision versus excision plus radiotherapy) and who developed a local recurrence were identified. Histology was reviewed for 116 cases; oestrogen and progesterone receptor status, and HER2/ neu and p53 overexpression were assessed for 71 cases. Comparing the primary DCIS and the invasive or non-invasive recurrence, concordant histology was found in 62%, and identical marker expression in 63%. Although 11% of the recurrences developed at a distance from the primary DCIS, nearly all these showed the same histological and immunohistochemical profile. 5 patients developed well-differentiated DCIS or grade I invasive carcinoma after poorly differentiated DCIS. Although these recurrences occurred in the same quadrant as the primary DCIS, they may be considered as second primary tumours. Only 4 patients developed poorly differentiated DCIS or grade III invasive carcinoma after well differentiated DCIS. We conclude that in most cases the primary DCIS and its local recurrence are related histologically or by marker expression, suggesting that local recurrence usually reflects outgrowth of residual DCIS; progression of well differentiated DCIS towards poorly differentiated DCIS or grade III invasive carcinoma is a non-frequent event.
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PMID:Histological type and marker expression of the primary tumour compared with its local recurrence after breast-conserving therapy for ductal carcinoma in situ. 1120 51

The gene for the steroid receptor coactivator amplified in breast cancer 1 (AIBI), located on chromosome 20q12, is overexpressed at the mRNA level in up to 60% of primary breast carcinomas; however, only 5% of these tumors show DNA amplification. The transcription factors and signaling pathways relevant to breast cancer, which in the absence of DNA amplification are responsible for and targeted by elevated levels of AIBI mRNA, are unknown. In the present study, in situ hybridization was used to examine AIB1 mRNA expression in 93 breast carcinomas of varying histological grade and immunohistochemical profile. AIB1 mRNA was overexpressed relative to normal breast tissue in 26 of 83 (31%) invasive tumors. This was found to associate with high tumor grade (P = 0.0006), lack of immunohistochemical staining for the steroid receptors estrogen receptor (P = 0.002) and progesterone receptor (P = 0.002), and strong protein staining for p53 (P = 0.01) and HER2/neu (P = 0.002). These findings suggest that AIB1 overexpression may impact on breast cancer by a mechanism not wholly dependent on steroid receptor coexpression and which may involve other oncogenic events, such as p53 protein stabilization and HER2/neu overexpression.
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PMID:Overexpression of the steroid receptor coactivator AIB1 in breast cancer correlates with the absence of estrogen and progesterone receptors and positivity for p53 and HER2/neu. 1122 79

The most important differential diagnosis of specialized intestinal columnar cell metaplasia (Barrett's-mucosa) is the intestinal metaplasia of the cardia mucosa (possibly caused by Helicobacter infection). Furthermore it happens from time to time that Barrett's regenerative epithelium is overdiagnosed as low-grade dysplasia (unequivocal intraepithelial neoplasia). This might explain the disappearance of many low-grade dysplasias during further follow-up. Mucosal adenocarcinomas are often underdiagnosed as dysplastic lesions. Therefore many authors tried to establish molecular methods for improvement of the diagnostic possibilities. Immunohistochemistry or PCR with p53 and HER 2-neu might give at least some help but a negative reaction does not exclude a neoplasia in every case. The gold standard is careful endoscopy and biopsy taking with good documentation of the endoscopical findings and most important still the routine H&E stain are the only reliable diagnostic tools.
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PMID:[50 years of Barrett esophagus. Current diagnostic possibilities in pathology]. 1122 47

Several new cytotoxic agents with activity in relapsed ovarian cancer are being combined with paclitaxel plus platinum as the first step to assess their impact in randomized trials against the standard treatment. These include topotecan, gemcitabine, epirubicin, and liposomal doxorubicin. Because of overlapping toxicities, there have been challenges in combining some of these agents in full dose with combination paclitaxel plus platinum. These have been overcome by use of sequenced administration. In addition to these new agents, novel non-cytotoxic drugs targeting specific signaling molecules or the tumor microenvironment provide additional avenues for clinical investigation. Many of these agents are rational to assess in ovarian cancer where laboratory research has pinpointed a number of alterations in molecules involved in cell signaling and cell cycle control. Examples include the antibody to HER 2/neu, agents targeting protein kinase C alpha, the p53 gene, and matrix metalloproteinase inhibitors. The challenges facing their assessment include how to determine adequate dosing when toxic effects are minimal and how to assess evidence of antitumor activity, short of conducting randomized studies. Finally, how best to use such agents together with conventional chemotherapy, in combination or in sequence, is unknown. Large clinical studies with some of these agents will provide some answers to their impact and how best to use them in the first-line management of advanced epithelial ovarian cancer.
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PMID:New cytotoxics and non-cytotoxics in epithelial ovarian cancer. 1124 Jul 31

Breast tumor development and progression are thought to occur through a complex, multistep process, including oncogene activation (eg HER2/neu) and mutation or loss of tumor suppressor genes (eg p53). Determining the function of genetic alterations in breast carcinoma tumorigenesis and metastasis has been the focus of intensive research efforts for several decades. One group of proteins that play a critical role in breast cancer cell signaling pathways are tyrosine kinases. Overexpression of the tyrosine kinase HER2/neu is observed in many human breast cancers and is positively correlated with enhanced tumorigenesis. Recently, another tyrosine kinase, Syk, has been implicated as an important inhibitor of breast cancer cell growth and metastasis. This recent finding was unexpected, since Syk function has been predominantly linked to hematopoietic cell signaling, and is discussed further in this commentary.
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PMID:Syk: a new player in the field of breast cancer. 1125 Jul 39

mdm2 is part of a complex mechanism that regulates the expression of p53 as well as the function of Rb, p19ARF, and other genes. In humans, mdm2 dysregulation is associated with gene amplification. This study was undertaken to characterize altered mdm2 expression in a cohort of 38 invasive breast cancers and 9 normal breast specimens. Reverse-transcription PCR with primers spanning the entire open reading frame of the mdm2 gene in breast tissue RNA samples generated PCR products of full-length mdm2 (1526 bp) as well as smaller products (653, 281, 254, and 219 bp). Sequence analysis demonstrated that the 653-bp product was an alternatively spliced product (defined as splicing at the exon/intron boundary consensus sites), whereas the 281, 254, and 219 bp mdm2 products were aberrantly spliced products (splicing at sites not considered to be exon/intron boundary sites). Reverse-transcription-PCR with normal breast tissue RNA samples yielded only the 1526-bp product in five samples and the 1526-bp product and the 653-bp product in four samples. The 653-bp alternatively spliced product was expressed in 21% of breast cancers, and the smaller, aberrantly spliced mRNA products (281 bp, 254 bp, and/or 219 bp) were expressed in 16% of breast cancers. The protein products predicted by the alternatively spliced mRNAs and the aberrantly spliced mRNAs lacked either the entire binding domain for p53 or the majority of the binding domain for p53. Immunohistochemical analysis of HER2/neu (c-erbB2), estrogen receptor, progesterone receptor, epidermal growth factor receptor, and p53 protein was performed. p53 sequence alterations were identified by mismatch detection and confirmed by p53 oligonucleotide microarray technology. An association was demonstrated between the expression of aberrantly and/or alternatively spliced mdm2 mRNAs and a lack of progesterone receptor. An association was also demonstrated between mdm2 aberrantly and/or alternatively expression products and the presence of p53 tumor suppressor gene mutations. mdm2 is transcribed from two different promoters: one, p53-dependent, and the other, p53-independent. The 5' untranslated region of the transcripts was evaluated to determine the promoter usage in each breast cancer specimen. No correlation was observed between mdm2 splice products and promoter usage. The presence of aberrant expression products of mdm2 in breast cancer specimens was correlated with a shortened overall patient survival. These observations suggest that mdm2 expression is altered in invasive breast cancer and is associated with more aggressive disease.
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PMID:Alternative and aberrant messenger RNA splicing of the mdm2 oncogene in invasive breast cancer. 1130 11

Transgenic mice expressing specific oncogenes usually develop tumors in a stochastic fashion suggesting that tumor progression is a multi-step process. To gain further understanding of the interactions between oncogenes and tumor suppressor genes during tumorigenesis, we have crossed a transgenic strain (TG.NK) carrying an activated c-neu oncogene driven by the MMTV enhancer/promoter with p53-deficient mice. c-neu transgenic mice have stochastic breast tumor formation and normal appearing salivary glands. However, c-neu mice heterozygous for a p53 deletion develop parotid gland tumors and loose their wild type p53 allele. c-neu mice with a homozygous p53 deletion have increased rates of parotid tumor onset suggesting that inactivation of p53 is required and sufficient for parotid gland transformation in the presence of activated c-neu. In contrast to the dramatic effect of p53 in parotid gland transformation, p53 loss has little effect on the rate or stochastic appearance of mammary tumors. In addition, p53 loss was accompanied by the down regulation of p21 in parotid gland tumors but not breast tumors. The parotid gland tumors were aneuploid and demonstrated increased levels of Cyclin D1 expression. These observations suggest that in c-neu transgenic mice, p53 alterations have differential tissue effects and may be influenced by the tissue specific expression of genes influencing p53 activity.
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PMID:Inactivation of p53 tumor suppressor gene acts synergistically with c-neu oncogene in salivary gland tumorigenesis. 1131 88


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