Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0242379 (lung cancer)
 71,905 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Accumulating evidence indicates that lung cancer arises due to multiple genetic changes in both dominant oncogenes, such as ras, and tumor suppressor genes, such as p53. In this report we examined whether the wild-type p53 gene is able to suppress in vitro and/or in vivo cellular growth of lung cancer cell lines which carry multiple genetic abnormalities. Introduction of a wild-type p53 complementary DNA expression vector into lung cancer cell lines carrying either a homozygous deletion (NCI-H358) or a missense mutation (NCI-H23) in the p53 gene greatly suppressed tumor cell growth. In contrast, p53 expression vectors bearing lung cancer derived mutations affecting single amino acids had lost this growth suppressing ability.
 ...
PMID:Wild-type but not mutant p53 suppresses the growth of human lung cancer cells bearing multiple genetic lesions. 155 36

We investigated the immunocytochemical staining and immunoblotting characteristics of 33 different p53 mutant proteins identified in lung cancer cell lines (18 small-cell lung cancer and 15 non-small-cell lung cancer) using monoclonal antibodies pAbs 240, 421 and 1801. The p53 mutants studied were representative of those found in lung cancer and included three deletions, four nonsense, seven splicing and 19 missense lesions. Control cell lines included six B-lymphoblastoid cell lines and two lung cancer cell lines without p53 mutations. Immunocytochemistry demonstrated 16 cell lines (48%) with definite overexpression of p53 protein (the high-expresser group of mutants), while in the remainder of cases either no p53 expression or low levels of p53 protein expression were found (the low-expresser group of mutants). The type of p53 mutation correlated with the expresser group. High expressers all had p53 missense mutations in exons 5-8, and immunocytochemistry identified 16/17 (94%) of these mutants. Several classes of p53 mutations occur in the low-expresser groups: deletions, splicing mutants, nonsense mutants and missense mutations outside of exons 5-8 all resulted in very low or undetectable levels of p53 protein. We conclude that there are low- and high-expression groups of p53 mutants in lung cancer and that the detection of protein expression in tumor cells by immunocytochemistry and immunoblotting is dependent upon the type of mutation of the p53 tumor-suppressor gene.
 ...
PMID:Expression of mutant p53 proteins in lung cancer correlates with the class of p53 gene mutation. 156 69

Squamous, large cell, and adenocarcinoma, collectively termed non-small cell lung cancer (NSCLC), are diagnosed in approximately 75% of patients with lung cancer in the United States. The treatment of these three tumor cell types is approached in virtually identical fashion because, in contrast to small cell carcinoma of the lung, NSCLC more frequently presents with localized disease at the time of diagnosis and is thus more often amenable to surgical resection but less frequently responds to chemotherapy and irradiation. Cigarette smoking is etiologically related to the development of NSCLC in the great majority of cases. Genetic mutations in dominant oncogenes such as K-ras, loss of genetic material on chromosomes 3p, 11p, and 17p, and deletions or mutations in tumor suppressor genes such as rb and p53 have been documented in NSCLC tumors and tumor cell lines. NSCLC is diagnosed because of symptoms related to the primary tumor or regional or distant metastases, as an incidental finding on chest radiograph, or rarely because of a paraneoplastic syndrome such as hypercalcemia or hypertrophic pulmonary osteoarthropathy. Screening smokers with periodic chest radiographs and sputum cytologic examination has not been shown to reduce mortality. The diagnosis of NSCLC is usually established by fiberoptic bronchoscopy or percutaneous fine-needle aspiration, by biopsy of a regional or distant metastatic site, or at the time of thoracotomy. Pathologically, NSCLC arises in a setting of bronchial mucosal metaplasia and dysplasia that progressively increase over time. Squamous carcinoma more often presents as a central endobronchial lesion, while large cell and adenocarcinoma have a tendency to arise in the lung periphery and invade the pleura. Once the diagnosis is made, the extent of tumor dissemination is determined. Since most NSCLC patients who survive 5 years or longer have undergone surgical resection of their cancers, the focus of the staging process is to determine whether the patient is a candidate for thoracotomy with curative intent. The dominant prognostic factors in NSCLC are extent of tumor dissemination, ambulatory or performance status, and degree of weight loss. Stages I and II NSCLC, which are confined within the pleural reflection, are managed by surgical resection whenever possible, with approximate 5-year survival of 45% and 25%, respectively. Patients with stage IIIa cancers, in which the primary tumor has extended through the pleura or metastasized to ipsilateral or subcarinal lymph nodes, can occasionally be surgically resected but are often managed with definitive thoracic irradiation and have 5-year survival of approximately 15%.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Non-small cell lung cancer. Part I: Biology, diagnosis, and staging. 164 34

During the past few years molecular genetics has been providing answers concerning the mechanisms that are involved in the pathogenesis of human malignancies. Essentially two different mechanisms are involved. One results in the activation of cellular protooncogenes. This activation can occur by activation of transcription, mutation, or gene fusion. Chromosomal translocations and inversions in malignant cells have provided very powerful tools to identify and characterize genes involved in malignant transformation and to probes specific for breakpoint cluster regions are being used extensively for the diagnosis, prognosis, and clinical monitoring of hematopoietic malignancies. The other mechanism results in loss of function of cancer suppressor genes or antioncogenes. Loss of heterozygosity at specific sites of the human genome has provided the means to identify, by the molecular genetic approach, genes the function of which is eliminated or suppressed in human cancers. During the last few years a number of such genes, such as Rb and p53, have been identified and characterized. By this approach a potential candidate involved in the 3p deletion characteristic of lung cancer has been identified. Interestingly, this gene codes for a protein tyrosine phosphatase (14). If this gene should turn out to be involved in the pathogenesis of lung and kidney tumors, it will indicate that transmembrane protein tyrosine phosphatase may represent a class of tumor suppressors.
 ...
PMID:Genetic approaches to the study of the molecular basis of human cancer. 165 9

Human aortic endothelial cells, isolated at autopsy from a 52-year-old male dying from lung cancer, were treated with simian virus 40 (SV40). One colony was isolated from the infected endothelial cell culture 4 weeks after infection. The cells expressed SV40 large T antigen and p53 protein (p53) in their nuclei but lacted the characteristics of a transformed phenotype. The cells grew well in a monolayer over the 97th passage and exhibited Factor VIII-related antigen, Ulex europaeus 1 agglutinin (UEA-1) as endothelial cell markers, and a well-developed fibronectin network. The amount of prostacyclin synthesized by the cells was less than the amount synthesized by normal aortic or umbilical cord vein endothelial cells. The cells produced relatively large amounts of procollagenase, and 12-o-tetradecanoyl-phorbol-13-acetate (TPA) augmented the ability of the cells to produce this enzyme. These immortalized human aortic endothelial cells, which have some characteristics of normal endothelial cells and, like capillary endothelial cells, have the ability to produce collagenase, will probably prove useful for studies of atherosclerosis and angiogenesis.
 ...
PMID:Collagenase production by immortalized human aortic endothelial cells infected with simian virus 40. 167 13

Squamous, large cell, and adenocarcinoma, collectively termed non-small cell lung cancer (NSCLC), are diagnosed in approximately 75% of patients with lung cancer in the United States. The treatment of these three tumor cell types is approached in virtually identical fashion because, in contrast to small cell carcinoma of the lung, NSCLC more frequently presents with localized disease at the time of diagnosis and is thus more often amenable to surgical resection but less frequently responds to chemotherapy and irradiation. Cigarette smoking is etiologically related to the development of NSCLC in the great majority of cases. Genetic mutations in dominant oncogenes such as K-ras, loss of genetic material on chromosomes 3p, 11p, and 17p, and deletions or mutations in tumor suppressor genes such as rb and p53 have been documented in NSCLC tumors and tumor cell lines. NSCLC is diagnosed because of symptoms related to the primary tumor or regional or distant metastases, as an incidental finding on chest radiograph, or rarely because of a paraneoplastic syndrome such as hypercalcemia or hypertrophic pulmonary osteoarthropathy. Screening smokers with periodic chest radiographs and sputum cytologic examination has not been shown to reduce mortality. The diagnosis of NSCLC is usually established by fiberoptic bronchoscopy or percutaneous fine-needle aspiration, by biopsy of a regional or distant metastatic site, or at the time of thoracotomy. Pathologically, NSCLC arises in a setting of bronchial mucosal metaplasia and dysplasia that progressively increase over time. Squamous carcinoma more often presents as a central endobronchial lesion, while large cell and adenocarcinoma have a tendency to arise in the lung periphery and invade the pleura. Once the diagnosis is made, the extent of tumor dissemination is determined. Since most NSCLC patients who survive 5 years or longer have undergone surgical resection of their cancers, the focus of the staging process is to determine whether the patient is a candidate for thoracotomy with curative intent. The dominant prognostic factors in NSCLC are extent of tumor dissemination, ambulatory or performance status, and degree of weight loss. Stages I and II NSCLC, which are confined within the pleural reflection, are managed by surgical resection whenever possible, with approximate 5-year survival of 45% and 25%, respectively. Patients with stage IIIa cancers, in which the primary tumor has extended through the pleura or metastasized to ipsilateral or subcarinal lymph nodes, can occasionally be surgically resected but are often managed with definitive thoracic irradiation and have 5-year survival of approximately 15%.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Non-small cell lung cancer. Part II: Treatment. 171 39

Approximately 4% of cytosine residues in human DNA are modified post-synthetically into 5-methylcytosine (5mC) which is the only modified base present in vertebrate DNA. The function of 5mC is not fully understood, but methylation of promoter regions is often associated with transcriptional inactivity and may be part of a gene silencing mechanism. While undermethylation of promoter regions is correlated with expression, the same does not seem to be true for the remainder of genes since many genes are expressed while containing 5mC in their coding regions. This is significant because 5mC is known to be inherently mutagenic and it has been suggested that it is responsible for 30-40% of all human germline point mutations. We have used direct genomic sequencing to examine the methylation status of CpG sequences which serve as potential methylation sites in the human p53 gene. These sites, which are known to be hotspots for mutations in several human cancers, were found to be methylated in the target human tissues examined. The results suggest that 5mC may play a substantial role as an endogenous mutagen in the p53 gene and that the generation of these mutations does not require the direct interaction of a carcinogen with DNA. We have also compared the spectrum of p53 mutations reported in the literature for various human tumors. The patterns of mutations seen in different tumor types vary considerably and 5mC contributes to 63% of point mutations in colorectal cancer but only 13% in lung cancer. Mutations in lung cancer are therefore caused by a different mechanism than colorectal cancer and this presumably requires the direct interaction of carcinogens with DNA. Assessment of the proportion of 5mC induced mutations in the p53 gene therefore allows for an estimate of the relative importance of endogenous and exogenous mechanisms of carcinogenesis.
 ...
PMID:5-Methylcytosine as an endogenous mutagen in the p53 tumor suppressor gene. 184 42

Examples of practical approaches to molecular epidemiology of human cancer are described. Biomarkers of carcinogen exposure or inherited host factors for cancer susceptibility are discussed. Major advances have been made in the detection of carcinogenmacromolecular adducts through the use of high performance liquid chromatography, immunoaffinity chromatography, the 32P-postlabeling assay, enzyme immunoassays, gas chromatography/mass spectroscopy and synchronous spectrophotofluorimetry. The polycyclic aromatic hydrocarbon-DNA adducts are the most extensively studied in this field and together with antibodies to these adducts found in human serum, they have become useful indicators of exposure to carcinogens. Assays for various kinds of alkyl-DNA adducts have also been developed and the presence of these adducts have been documented in human tissues. Carcinogen-protein adducts have proven to be useful molecular dosimeters of carcinogen exposure. For example, 4-aminobiphenyl hemoglobin adducts are highly correlated with exposure to tobacco smoke. The study of the molecular aspects of interindividual differences in the metabolism and activation of xenobiotics and other genetic markers [DNA-restriction fragment length polymorphisms (RFLPs), mutations, and functional loss of specific genes in carcinogenesis] is an emerging new field that is discussed in the context of genetic susceptibility to cancer. The cytochrome P450 phenotypes and acetylation phenotype are examples of genetic markers that indicate an individual's potential for metabolism of exogenous substances. Further, inherited genetic polymorphic markers, e.g., DNA-RFLPs at protooncogene loci (HRAS-1 and L-myc) have been examined in a case-control study of lung cancer. Data concerning mutations of protooncogenes (H-, K-, and N-RAS) and tumor suppressor genes (retinoblastoma and p53 genes) in various common cancers are providing evidence of multiple genetic lesions that occur during the multistage process of carcinogenesis.
 ...
PMID:Biochemical and molecular epidemiology of cancer. 191 Jun 3

The nuclear protein p53 has been measured in archival lung cancer biopsies. The monoclonal antibody PAb 1801, which recognizes human p53, was used. After immunostaining, the nuclei prepared from paraffin-embedded tissue were stained with propidium iodide for simultaneous measurement of DNA content; 17 of 24 lung cancers were p53 positive. The S-phase fraction in positive tumors was 22.9 +/- 6.4%, as compared to 13.6 +/- 6.1% in negative tumors (P less than 0.02). In ten of the positive tumors (two small cell carcinomas and eight non-small cell carcinomas), the p53 expression varied through cell cycle, whereas in seven tumors (five small cell carcinomas and two non-small cell carcinomas), no such variation of p53 expression was observed. Freezing the nuclear suspensions did not substantially reduce the p53 signals. Control experiments with the SV40-transformed human foreskin fibroblast cell line HSF4-T12 showed that the enzymatic digestion utilized to dissociate paraffin-embedded tissue did not significantly reduce p53 fluorescence. Immunohistochemical staining of biopsy specimens indicated that only cancer cells were overexpressing p53. In conclusion, using the monoclonal antibody PAb 1801, p53 is detectable in cell nuclei prepared from paraffin-embedded bronchial carcinoma biopsies. P53 positive tumors have increased proliferative activity compared to p53 negative tumors. Furthermore, the lack of cell cycle variation of p53 in small cell carcinomas indicates that this pattern may be related to high-grade malignancy.
 ...
PMID:Flow cytometric measurement of p53 protein expression and DNA content in paraffin-embedded tissue from bronchial carcinomas. 193 58

An understanding of the molecular pathogenesis of lung cancer has evolved from classic cytogenetic studies and the use of restriction fragment length polymorphisms to encompass the definition of specific genetic abnormalities associated with this disease. Activation of the dominant class of oncogenes is frequent, with involvement of the ras and myc families of genes being the best defined. Several examples of inactivation at specific loci exist and have been related to the presence of tumor suppressor genes, most notably the retinoblastoma gene, p53, and a putative gene located on the short arm of chromosome 3. As our understanding of the nature and interactions between these numerous genetic events evolves, new opportunities for early diagnosis, prevention, and treatment will arise.
 ...
PMID:Dominant oncogenes and tumor suppressor genes in the pathogenesis of lung cancer. 196 50


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