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)

Nitric oxide (NO) is a pleiotropic regulator, critical to numerous biological processes, including vasodilatation, neurotransmission and macrophage-mediated immunity. The family of nitric oxide synthases (NOS) comprises inducible NOS (iNOS), endothelia (eNOS), and neuronal NOS (nNOS). Interestingly, various studies have shown that all three isoforms can be involved in promoting or inhibiting the etiology of cancer. NOS activity has been detected in tumour cells of various histogenetic origins and has been associated with tumour grade, proliferation rate and expression of important signaling components associated with cancer development such as the oestrogen receptor. It appears that high levels of NOS expression (for example, generated by activated macrophages) may be cytostatic or cytotoxic for tumor cells, whereas low level activity can have the opposite effect and promote tumour growth. Paradoxically therefore, NO (and related reactive nitrogen species) may have both genotoxic and angiogenic properties. Increased NO-generation in a cell may select mutant p53 cells and contribute to tumour angiogenesis by upregulating VEGF. In addition, NO may modulate tumour DNA repair mechanisms by upregulating p53, poly(ADP-ribose) polymerase (PARP) and the DNA-dependent protein kinase (DNA-PK). An understanding at the molecular level of the role of NO in cancer will have profound therapeutic implications for the diagnosis and treatment of disease.
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PMID:The role of nitric oxide in cancer. 1252 89

A biological characterisation carried out on 14,007 primary breast cancers provided evidence in favour of a relation between advanced age and favourable features (positivity for oestrogen/progesterone receptors, low proliferative rate, absence of p53 accumulation, bcl-2 overexpression, diploid DNA content), showed a similar pattern of association between patho-biological variables regardless of patient age, and demonstrated a relation between biological variables and disease outcome in the elderly, comparable to that already reported for younger patients. In fact, oestrogen receptor and proliferative activity provided independent prognostic information either in node-negative or in node-positive tumours treated with radical or conservative surgery plus radiotherapy, alone or followed by adjuvant hormonal therapy. It would be thus reasonable to use biomarkers as a complement to clinico-pathological features in a 'risk-factor profile system' even for elderly patients, upon their validation in prospective studies and after assessing the cost-benefit of treatments planned on the basis of biological information.
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PMID:Primary breast cancer in elderly women: biological profile and relation with clinical outcome. 1263 42

The most appropriate systemic therapy for a population of patients with breast cancer is determined from clinical trial data. However, the heterogeneity of breast cancer is such that within a population individual patients derive variable benefit. There is therefore a need for predictive molecular factors in order that treatment can be individualised. This review describes the roles of HER-2, epidermal growth factor receptor (EGFR), oestrogen receptor (ER)/progesterone receptor (PgR), Ki67, Bcl-2, p53 and gene expression profiling in predicting responses to endocrine, cytotoxic and biological therapies. ER and PgR remain the only well-established predictive markers of responses to endocrine therapy, although HER-2/neu has an emerging role in this area and in choice of adjuvant chemotherapy. There are considerable methodological difficulties in identifying useful predictive factors but on the basis of current evidence other biomarkers add little additional information. The development of targeted therapies means that the molecular targets themselves may become useful predictive factors for directing use of these therapies. HER-2 already has an established role in this area, but the role of EGFR requires further elaboration. The use of DNA microarrays to assess gene expression profiles may revolutionise our ability to predict responses to therapy.
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PMID:Predictors of response to systemic therapy in breast cancer. 1263 8

The number of elderly women diagnosed with breast cancer by 2025, will increase by 72%. These elderly women do not yet participate in most screening programmes. One notes more favourable biological characteristics of the tumour, including more expression of steroid receptors (oestrogen receptor, progesterone receptor), low proliferative rate, good differentiation, normal p53 and low expression of epidermal growth factor. Elderly breast cancer patients are frequently treated with breast conservation, omitting axillary dissection, radiation therapy and chemotherapy. There is a paucity of data to substantiate that such an approach is better than a more radical one. The efficacy of chemotherapy and guidelines for its use vary by tumour stage and patient age. Drugs like modified anthracyclines, vinorelbine, the taxanes and capecitabine may be changing the paradigm of combination therapy superiority.
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PMID:Chemotherapy in the elderly with breast cancer. 1263 11

We previously reported that defects in apoptotic pathways (mutations in the TP53 gene) predicted resistance to doxorubicin monotherapy. The aim of this study was to evaluate whether cell proliferation, as assessed by mitotic frequency and Ki-67 levels, may provide additional predictive information in the same tumours and to assess any potential correlations between these markers and mutations in the TP53 gene and erbB-2 overexpression. Surgical specimens were obtained from ninety locally advanced breast cancers before commencing primary chemotherapy consisting of weekly doxorubicin (14 mg/m2) for 16 weeks. 38% of the patients had a partial response (PR) to therapy, 52% had stable disease (SD) while 10% had progressive disease (PD). Univariate analysis showed a significant association between a high cell proliferation rate (expressed as a high mitotic frequency) and resistance to doxorubicin (P = 0.001). Further analyses revealed this association to be limited to the subgroup of tumour expressing wild-type TP53 (P = 0.016), and TP53 mutation status was the only factor predicting drug resistance in the multivariate analyses. The finding that a high mitotic frequency, as well as a high Ki-67 staining, correlated to TP53 mutations (P = 0.001 for both), suggests TP53 mutations are the key predictor of drug resistance, although cell proliferation may play an additional role in tumours harbouring wild-type TP53. Regarding overall (OS) and relapse-free survival (RFS), multivariate analyses (Cox' proportional hazards regression) revealed a high histological grade and negative oestrogen receptor (ER) status to be the variables that were most strongly related to breast cancer death (P = 0.001 and P = 0.001, respectively). A key reason for this difference with respect to the factors predicting chemotherapy resistance could be due to the adjuvant use of tamoxifen in all patients harbouring ER-positive tumours.
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PMID:Predictive value of tumour cell proliferation in locally advanced breast cancer treated with neoadjuvant chemotherapy. 1275 73

The alpha isoform of Topoisomerase IIalpha (Topo IIalpha) is a proliferation marker as well as a target for several chemotherapeutic agents such as anthracyclines. In vitro studies have demonstrated the relationship between the Topo IIalpha expression level and chemosensitivity of target cancer cells. To verify this effect in vivo, we selected 125 patients presenting with T(2)>3 cm and T(3) N(0-1) M(0) breast tumours who were treated by six cycles of primary chemotherapy, including epirubicin before any surgery. Therapy response was assessed by clinical and X-ray mammogram measurements of tumour shrinkage. The pretherapeutic core biopsies were immunostained with a monoclonal antibody (Ki-S7) against Topo IIalpha. Ki-S7 positivity ranged from 0 to 50% (median, 15%). A high percentage of Ki-S7-positive cells (>15%) was associated with tumour regression under chemotherapy (OR=2.88, CI: 1.3-6.4, P=0.004). Ki-S7 further emerged as an independent predictor of tumour regression (OR=3.34, CI: 1.41-7.93, P=0.006), together with tumour size of less than 40 mm (OR=3.82, CI: 1.58-9.25, P=0.002) and negative oestrogen receptor (ER) status (OR=3.35, CI: 1.43-7.86, P=0.005), in a multivariate analysis including tumour size, SBR grade, ER and PR status, Ki-67, p53 and Her-2/neu. Our clinical results confirm in vitro data on the relationship between Topo IIalpha expression and tumour chemosensitivity and thus may have important practical implications.
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PMID:DNA topoisomerase IIalpha expression and the response toprimary chemotherapy in breast cancer. 1291 75

Literature data suggest that breast cancers occurring in young patients may be different from those arising in older women. In this study the clinicopathologic characteristics of 50 patients under 40 years of age were compared with those of patients aged over 60. Patients under 40 years old more frequently had a family history of breast cancer than did older patients (24% vs 17%) and had more often used oral contraceptives (29% vs 13%); on average they had experienced menarche 1 year earlier. For early onset breast carcinomas there was a higher frequency of grade 3 tumours (38% vs 17%) and oestrogen receptor negativity (46% vs 20%). In addition, in younger patients the carcinomas were mostly DNA aneuploid (78% vs 58%), with a higher proliferation rate (48% vs 26%) and more frequent c-erbB-2 overexpression (48% vs 26%) and p53 alteration (30% vs 8%). Our data demonstrate that breast cancers arising in young women have a significantly different biopathological profile from those in older patients, with a predominance of unfavourable prognostic parameters.
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PMID:Breast cancer in young women: clinicopathological features and biological specificity. 1465 8

Epidemiological studies over the past several decades have consistently supported the concept that a proportion of breast cancers develop as the result of an inherited familial predisposition. However, until recently our understanding and knowledge of the underlying genetic processes involved have been limited. Current advances in molecular biology have shown that hereditary breast cancer may arise as the result of mutations of several specific gene loci including BRCA1, BRCA2, ATM gene, PTEN and p53. Several other less frequently occurring predisposition genes such as the androgen receptor gene (AR), the HNPCC genes and the oestrogen receptor gene may also be involved, but to a lesser extent. It is estimated that approximately 5-10% of all breast cancers involve one of these inherited predisposition genes, with BRCA1 and BRCA2 accounting for up to 90% of this group. Mutation analysis is complex in nature and is presently in a developmental and evolving phase, for which reason genetic testing should be offered on a selective basis and through genetic counselling clinics. This report reviews the current knowledge and roles of the various predisposition genes and discusses the management implications for both affected and nonaffected members of breast cancer families. Comprehensive and informative counselling is critical for women with an inherited predisposition to breast cancer and this has led to the evolution of familial cancer clinics involving a multi-disciplinary specialist team approach. Familial cancer clinics can provide individuals with information about their risk of developing breast cancer and offer advice regarding the various management options presently available.
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PMID:The management of familial breast cancer. 1473 74

The aim of this study was to determine the chemosensitivity of infiltrating lobular breast carcinoma (ILC) in comparison with infiltrating ductal carcinoma (IDC). Between 1987 and 1995, 457 patients with invasive T2>3 cm-T4 breast carcinomas were treated with primary chemotherapy (CT), surgery, radiation therapy. Clinical response, the possibility of breast preservation, pathological response and survival were evaluated according to the histological type. In order to evaluate the biological differences between ILC and IDC patients and their implication with regard to tumour chemosensitivity, additional immunohistochemical stainings (oestrogen receptor (ER), Bcl2, p53, c-erbB-2 and Ki67) were performed on 129 pretherapeutical specimens. 38 (8.3%) ILC were diagnosed by core needle biopsy before CT. ILC was an independent predictor of a poor clinical response (P=0.02) and ineligibility for breast-conserving surgery after neoadjuvant chemotherapy (P=0.03). Histological and biological factors predicting a poor response to CT (histological grade, ER, Ki67 and p53 status) were more frequent in ILC than in IDC patients. After a median follow-up of 98 months (range: 3-166), the low chemosensitivity of ILC did not result in a survival disadvantage. Our results demonstrate that ILC achieved a lower response to CT than IDC because of their immunohistochemical profile. Preoperative CT did not allow a high rate of conservative treatment for ILC and therefore the use of neoadjuvant CT for ILC patients should be questioned.
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PMID:The poor responsiveness of infiltrating lobular breast carcinomas to neoadjuvant chemotherapy can be explained by their biological profile. 1474 51

Distinct parallel cytogenetic pathways in breast carcinogenesis could be identified in recent years. Nevertheless, it remained unclear as to which tumours may have progressed in grade or which patterns of cytogenetic alteration may define the switch from an in situ towards an invasive lesion. In order to gain more detailed insights into cytogenetic mechanisms of the pathogenesis of breast cancer, the chromosomal imbalances of 206 invasive breast cancer cases were characterised by means of comparative genomic hybridisation (CGH). CGH data were subjected to hierarchical cluster analysis and the results were further compared with immunohistochemical findings on tissue arrays from the same breast cancer cases. The combined analysis of immunohistochemical and cytogenetic data provided evidence that carcinomas with gains of 7p, and to a lesser extent losses of 9q and gains of 5p, are a distinct subgroup within the spectrum of ductal invasive grade 3 breast carcinomas. These aberrations were associated with a high degree of cytogenetic instability (16.6 alterations per case on average), 16q-losses in over 70% of these cases, strong oestrogen receptor expression and absence of strong expression of p53, c-erbB2 and Ck 5. These characteristics provide strong support for the hypothesis that these tumours may develop through stages of well- and perhaps intermediately differentiated breast cancers. Our results therefore underline the existence of several parallel and also stepwise progression pathways towards breast cancer.
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PMID:Deciphering a subgroup of breast carcinomas with putative progression of grade during carcinogenesis revealed by comparative genomic hybridisation (CGH) and immunohistochemistry. 1505 66


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