Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the last ten years considerable progress has been made in small-cell lung carcinoma (SCLC) biology, along with the technical progress made in molecular biology. This progress now allows us to propose a model for the genesis and the development of this type of tumor. Tobacco, the principal causal factor plays a dual role. In bringing about secretion of growth factors by the bronchial epithelia, usually involved in the normal development of lungs, and by functioning autocrinally and paracrinally, it facilitates the occurrence of mitotic mutations. Without directly contributing to cellular transformation, this autocrine functioning also gives a selective advantage to cells going through transformation or immortalization. The procarcinogenic or carcinogenic agents contained in tobacco smoke, whose level of production could be genetically determined, would also contribute to the accumulation of mutations affecting both suppressor genes and oncogenes. Two tumour suppressor genes have been identified: RB1 and P53. At least one other putative tumour suppressor gene has constantly been implied. It lies on the short arm of chromosome 3. There could also be the possibility of detecting subjects susceptible to developing an SCLC, a functional hemizygote still needing evaluation. The activated oncogenes principally belongs to the myc family. Their activation could correspond with the appearance of cellular clones having aggressive behavior independent of growth factors, chemoresistant and more metastatic. SCLC may be distinguished from other malignant lung tumors by a fairly characteristic pattern consisting of the loss of suppressor genes and the activation of oncogenes. The links between the neuroendocrine properties of this type of tumor and its characteristic description are being clarified and will contribute to a better understanding of the relationship between the different types of lung tumors. From this biologic knowledge follow several therapeutic applications under investigation (blocking autocrine loop through anti-GRP antibodies), as well as potential applications (concerning the products of suppressor genes) and possible applications such as prevention oriented towards detection of high-risk subjects.
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PMID:[Biology of small-cell bronchogenic carcinoma: recent advances]. 132 50

Mutations in the p53 tumour suppressor gene are amongst the most frequent genetic abnormalities acquired in tumours. Recent studies in vitro suggest that mutant p53 destabilises the genome and facilitates development of aneuploidy. Here, in a study of 83 colorectal carcinomas, we demonstrate that alterations in p53 (detected by immunocytochemical stabilisation) precede and apparently facilitate divergence of aneuploid sub-clones. Aneuploidy in these tumours (but not those with normal p53) is predominantly in the subtetraploid range, suggesting that endoreduplication is important in its origin. This association with a specific phase of carcinoma progression is not shared by other commonly acquired genetic abnormalities in these tumours. These observations highlight the critical role of p53 in the regulation of abnormal chromosome replication and afford an explanation for the association between p53 abnormalities, aneuploidy and biological aggression in cancer.
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PMID:Stabilised p53 facilitates aneuploid clonal divergence in colorectal cancer. 847 57

Bladder cancer is clinically characterized by a high recurrence rate for superficial tumours up to 70% and by the invasiveness of advanced bladder cancer. To learn more about the biological behaviour of an individual bladder cancer different tumour markers have been investigated. The aim of our study was to compare the potential of aggression of both superficial and invasive bladder tumours by means of the proliferation marker Ki67, the tumour suppressor gene p53, the non metastasizing protein nm23 and the evaluation of DNA ploidy. We examined 36 patients, 28 with a bladder tumour (Ta-T4) and 8 without as a control group. For immunohistochemistry (Ki67, p53, nm23) we took paraffin sections and scored semiquantitatively under a microscope. The DNA cytophotometry was done on bladder washings by evaluating the DNA ploidy of single cells. The results showed that benign tissues were negative for Ki67 and p53 but positive for nm23. The DNA diagnosis was diploid for all benign samples. The superficial bladder cancer (Ta, T1) showed, in comparison to the invasive tumours, significantly lower numbers of aneuploid cells and a higher rate of p53 mutations. On the other hand the invasive tumours (T2-4) were correlated to significantly higher proliferation rates and higher potencies for metastasizing. The combination of the investigated tumour markers allowed a graduation of the biological behavior of an individual bladder cancer. Especially a high p53 mutation rate and a non aneuploid DNA diagnosis were indicators for the recurrence of superficial bladder tumours. Invasive growth of bladder cancer was characterized by high Ki67 proliferation and low nm23 protein binding.
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PMID:Immunohistochemical examinations (Ki67, p53, nm23) and DNA cytophotometry in bladder cancer. 1132 61

Prolactinoma is the most common pituitary tumour in adults. Macroprolactinomas, particularly in men, may occasionally exhibit a very aggressive clinical course as evidenced by progressive growth, invasion through bone into the sphenoid sinus, cavernous sinus, suprasellar region or the nasopharynx. Some may even progress to pituitary carcinoma with craniospinal or systemic metastases. Aggressive tumours have low cure rates despite appropriate medical and surgical treatment. The mechanisms underlying this aggressive biological behaviour have not yet been fully clarified. Recent immunohistochemical, molecular and genetic studies have provided some insight in this respect. Invasive prolactinomas may be associated with a high Ki-67/MIB-1 labelling index indicating increased cell proliferation, although this is not a universal finding. The AA polymorphism in the cyclin adenine (A)/guanine (G) gene is more frequently detected in invasive prolactinomas. Increased expression of the polysialylated neural cell adhesion molecule (NCAM) and reduced expression of the E-cadherin/catenin complex implies a contribution of altered cell-to-cell adhesion and cellular migration. Extracellular matrix components (ECM), matrix metalloproteinases (MMPs) and their inhibitors play important roles in the context of angiogenesis and invasion. The induction of fibroblast growth factor and vascular endothelial growth factor via oestrogen-induced overexpression of novel genes (PTTG, hst and Edpm5) enhance cell growth, proliferation and angiogenesis contributing to invasiveness in prolactinomas. Although mutations in proto-oncogenes like Ras are uncommon, loss of tumour suppressor genes at loci 11q13, 13q12-14, 10q and 1p seem to be associated with invasiveness. Of the described mechanisms, only reduced E-cadherin/catenin expression and overexpression of hst gene seem to be relatively specific markers for prolactinoma invasiveness compared with other pituitary adenomas. Further research is needed to clarify the molecular mechanisms behind the aggressive course of some prolactinomas to predict those with a potentially poor clinical outcome, and to devise treatments that will eventually enable the cure of these challenging tumours.
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PMID:What are the markers of aggressiveness in prolactinomas? Changes in cell biology, extracellular matrix components, angiogenesis and genetics. 1728 3

p53 has been studied intensively as a major tumour suppressor that detects oncogenic events in cancer cells and eliminates them through senescence (a permanent non-proliferative state) or apoptosis. Consistent with this role, p53 activity is compromised in a high proportion of all cancer types, either through mutation of the TP53 gene (encoding p53) or changes in the status of p53 modulators. p53 has additional roles, which may overlap with its tumour-suppressive capacity, in processes including the DNA damage response, metabolism, aging, stem cell differentiation and fertility. Moreover, many mutant p53 proteins, termed 'gain-of-function' (GOF), acquire new activities that help drive cancer aggression. p53 is regulated mainly through protein turnover and operates within a negative-feedback loop with its transcriptional target, MDM2 (murine double minute 2), an E3 ubiquitin ligase which mediates the ubiquitylation and proteasomal degradation of p53. Induction of p53 is achieved largely through uncoupling the p53-MDM2 interaction, leading to elevated p53 levels. Various stress stimuli acting on p53 (such as hyperproliferation and DNA damage) use different, but overlapping, mechanisms to achieve this. Additionally, p53 activity is regulated through critical context-specific or fine-tuning events, mediated primarily through post-translational mechanisms, particularly multi-site phosphorylation and acetylation. In the present review, I broadly examine these events, highlighting their regulatory contributions, their ability to integrate signals from cellular events towards providing most appropriate response to stress conditions and their importance for tumour suppression. These are fascinating aspects of molecular oncology that hold the key to understanding the molecular pathology of cancer and the routes by which it may be tackled therapeutically.
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PMID:Regulation of the p53 response and its relationship to cancer. 2620 89

Germline mutations in the BRCA2 tumour suppressor are associated with both an increased lifetime risk of developing prostate cancer (PCa) and increased risk of aggressive disease. To understand this aggression, here we profile the genomes and methylomes of localized PCa from 14 carriers of deleterious germline BRCA2 mutations (BRCA2-mutant PCa). We show that BRCA2-mutant PCa harbour increased genomic instability and a mutational profile that more closely resembles metastastic than localized disease. BRCA2-mutant PCa shows genomic and epigenomic dysregulation of the MED12L/MED12 axis, which is frequently dysregulated in metastatic castration-resistant prostate cancer (mCRPC). This dysregulation is enriched in BRCA2-mutant PCa harbouring intraductal carcinoma (IDC). Microdissection and sequencing of IDC and juxtaposed adjacent non-IDC invasive carcinoma in 10 patients demonstrates a common ancestor to both histopathologies. Overall we show that localized castration-sensitive BRCA2-mutant tumours are uniquely aggressive, due to de novo aberration in genes usually associated with metastatic disease, justifying aggressive initial treatment.
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PMID:Germline BRCA2 mutations drive prostate cancers with distinct evolutionary trajectories. 2811 48