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Query: UMLS:C0684249 (lung carcinoma)
 23,830 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mutational activation of ras oncogenes is frequently encountered in human tumors. For unexplained reasons, K-ras mutations are predominantly found in pancreatic cancer, colorectal cancer and adeno-carcinoma of the lung, N-ras is predominantly found in a subset of acute leukemias and in myelodysplastic syndromes, while H-ras mutations are rare. In most tumors, ras mutations are not clearly associated with specific clinical or biological features, but in lung cancer, childhood lymphoblastic leukemia and possibly in myelodysplastic syndromes ras mutations may predict a poor prognosis. Accumulating evidence suggests that exposure to chemical carcinogens is responsible for many ras mutations in humans.
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PMID:ras and human tumors. 142 Nov 68

A human non-small-cell lung carcinoma cell line, Calu-6 (from an anaplastic carcinoma), was transfected with the Ki-ras-related anti-oncogene Krev-1. Several transfectant lines were obtained that showed a reduced tumorigenicity in nude mice with respect to the parental and control transfected cell lines. This decrease was approximately 50% in tumor incidence at 4 wk after subcutaneous inoculation of the transfected cells. In addition, the volume of the Calu-6 revertant-derived tumors was three to 10 times smaller than that of the equivalent tumors produced by inoculation of the control cell line transfected with the neomycin-resistance gene. Krev-1--transfected cells that exhibited reduced tumorigenicity expressed Krev-1 mRNA and had variable numbers of copies of the Krev-1 gene. Moreover, Krev-1--transfected cells exhibited a more differentiated squamous epithelial morphology than the parental and control cell lines did. Moderately elevated levels of protein kinase C activity were detected in some revertant clones. Such activity correlated with the level of expression of Krev-1 mRNA in most cases. In summary, Krev-1 induced important morphological and biological changes in transfected Calu-6 cells that we interpreted as partial reversion of the malignant phenotype.
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PMID:Partial suppression of tumorigenicity in a human lung cancer cell line transfected with Krev-1. 148 16

Morphogenetic and molecular-biological features of the lung peripheral tumours (small-cell carcinoma, atypical and typical carcinoid) were studied on the surgical material from 68 patients. Spectrum of histologic, histochemical, immunohistochemical (immunohistochemistry of oncoproteins c-fos, c-myc, c-ras, c-sis and c-src) methods, DNA histospectrophotometry by plug-method, electron microscopy, semithin section morphometry, statistical and correlation analysis were used. Small-cell carcinoma is shown to be a heterogeneous group of tumours that includes tumours with endocrine cell differentiation, endocrine and epidermoid and/or glandular, undifferentiated cell carcinoma. Lymphocyte-like carcinoma and intermediate cell carcinoma with endocrine cell differentiation are distinguished from other types of lung carcinoma by their low, sometimes diploid DNA content that does not correlate with its malignancy as well as by a low level of expression of cell oncogenes c-fos, c-ras, c-sis. Small-cell carcinoma with endocrine cell differentiation, atypical and typical lung carcinoids represent a unique histogenetic group of endocrine lung tumours that differ from each other by the degree of anaplasia.
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PMID:[Peripheral small cell carcinoma, atypical and typical lung carcinoids (morphologic features, cell oncogene expression, DNA histospectrophotometry)]. 168 68

We established a human carcinoma cell line (KHC 287) from a patient with large-cell-typing lung carcinoma associated with marked leukocytosis. The culture supernatant of KHC 287 cells promoted granulocytic colony formation of human bone-marrow cells in semi-solid culture. Colony formation was almost completely suppressed by treatment of the supernatant with a monoclonal anti-granulocyte colony-stimulating factor (G-CSF) antibody. Not only G-CSF but also interleukin-1 alpha (IL-I alpha), IL-I beta and IL-6 were detected in the culture supernatant by an ELISA method. Northern blot analysis of KHC 287 cells revealed distinct expression of these cytokine genes. Southern blot hybridization of KHC 287 DNA showed 20- and 40-fold co-amplification of c-myc and c-ki-ras, respectively. The chloramphenicol acetyl transferase (CAT) activity was distinctly enhanced in the KHC 287 cells which were transfected with the 360 bp upstream region of G-CSF gene inserted into pSV00CAT, but not in non-G-CSF-producing tumor cell lines. These results suggest that overproduction of the transactivating factor(s) which binds to the 360 bp of the G-CSF upstream region is responsible for the abnormal expression of G-CSF gene in KHC 287 cell line.
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PMID:Analysis of abnormal expression of g-csf gene in a novel tumor cell line (KHC 287) elaborating G-CSF, IL-1 and IL-6 with co-amplification of c-myc and c-ki-ras. 171 Feb 8

The p53 tumor suppressor gene is frequently mutated and the K-ras oncogene is occasionally mutated in primary specimens of human lung carcinomas. These mutated genes also cooperate in the immortalization and neoplastic transformation of rodent cells. To determine whether these mutations are necessary for maintenance of the immortalized and/or neoplastically transformed states of human bronchial epithelial cells, the p53 gene and regions of the ras (K-, H-, and N-) genes were sequenced in nine human lung carcinoma cell lines. Detection of p53 mutations by polymerase chain amplification and direct DNA sequencing was corroborated by p53 immunocytochemistry and coimmunoprecipitation of p53 with heat shock protein 70. p53 and ras genes were frequently, but not always, mutated in the carcinoma cell lines. These data are consistent with the hypothesis that multiple genetic changes involving both protooncogenes and tumor suppressor genes occur during lung carcinogenesis.
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PMID:p53 mutations, ras mutations, and p53-heat shock 70 protein complexes in human lung carcinoma cell lines. 185 24

Six families of activated protooncogenes, ras, raf, fur, neu, jun and myc have so far been associated with human lung cancer. Human bronchial epithelial cells in vitro are being used to investigate the functional role of these specific oncogenes and growth regulatory genes in carcinogenesis and tumour progression. When transferred into normal human bronchial epithelial cells by the highly efficient protoplast fusion method, the v-Ha-ras oncogene initiates a cascade of events leading to decreased responsiveness of these cells to inducers of squamous differentiation, aneuploidy and, less frequently, 'immortality' and tumorigenicity with metastasis in athymic nude mice. Transfection of the SV40 T antigen gene results in nontumorigenic cell lines that have a nearly normal pathway of terminal squamous differentiation and can be transformed into malignant cells by transfected Ha-ras, N-ras or Ki-ras. The combination of transfected c-myc and c-raf-1 also transforms human bronchial epithelial cells into neoplastic cells that exhibit some phenotypic traits found in small-cell carcinomas. These and other results indicate that proto-oncogenes dysregulate the pathways of growth and differentiation of human bronchial epithelial cells and play an important role in human carcinogenesis. Analyses of allelic deletion and somatic cell hybrids are being used to identify the chromosomal localization of tumour suppressor genes. We have examined 54 non-small-cell bronchogenic carcinomas with 13 polymorphic markers. Loss of heterozygosity was more frequent than among 23 squamous-cell carcinomas than among 23 adenocarcinomas or eight large-cell carcinomas. Loss of heterozygosity for chromosome 17p was found in 89% of cases of squamous-cell carcinoma and 18% of adenocarcinomas. Analysis of chromosome 11 for allelic deletions revealed two commonly deleted regions (11p13 and 11p15.5). Somatic cell hybrids between normal human bronchial epithelial cells and Hut292DM, a lung carcinoma cell line, had a finite lifespan in vitro and were nontumorigenic in athymic nude mice. Tumour suppressive effects of individual or combinations of specific human chromosomes on Hut292DM are being examined by formation of microcell-cell hybrids. Chromosome 11 has tumour suppressor activity in these hybrids. Both of these studies suggest that tumour suppressor genes play a dominant role in lung carcinogenesis and provide in-vitro model systems for isolating these genes by subtraction library and insertional mutagenesis techniques.
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PMID:Role of oncogenes and tumour suppressor genes in human lung carcinogenesis. 185 68

In vitro and in vivo metastatic variants derived from Lewis lung carcinoma (3LL) were examined for the level of the expression of several growth-regulated genes, oncogenes, and transforming growth factor (TGF) genes. To determine whether the proliferative advantage of metastatic cells is due to an increased growth fraction of the cell population or to a deregulated expression of some growth-regulated genes, the mRNA levels of the S-phase-specific H3 histone gene were compared with that of some cell cycle-related genes (vimentin, calcyclin, c-myc, and p53) and oncogenes (Ki-ras, Ha-ras, c-sis, c-src, c-fes, and c-erb). In addition, to evaluate whether an autocrine pattern of cell proliferation is responsible for the proliferative advantage of metastatic cells, the level of the expression of TGF genes (alpha and beta 1) was studied. Northern blot analysis demonstrated that in 3LL metastatic variants the expression of TGF-alpha as well as the expression of all growth-regulated genes and oncogenes studied are similar. Only the TGF-beta 1 gene is expressed at higher levels in highly metastatic 3LL variants maintained either in vitro or in vivo. Data suggest that the proliferative advantage of 3LL metastatic cells is not due to a deregulated expression of some growth-regulated genes and oncogenes, but more likely is acquired through the expression of genes which might interfere with the ability of the tumor cells to escape hostile microenvironmental conditions.
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PMID:Differential expression of transforming growth factor-beta 1 gene in 3LL metastatic variants. 191 69

We have examined whether human placental extracts contain tumour-growth-inhibitory factors. One fraction (EAP) from such extracts inhibited growth, in soft agar, of Ha-ras-transformed BALB/c 3T3 cells and human squamous lung carcinoma A-2182 cells. However, this fraction had no effect on the anchorage-dependent growth of these cells, although there was a slight mitogenic activity on nontransformed cells. These data together with those on plating efficiency indicated no significant cytotoxicity of EAP on transformed cell lines. Although this fraction contained transforming growth factor beta (TGF beta), this cannot account for its inhibitory activity, since (a) pure TGF beta does not inhibit anchorage-dependent growth of Ha-ras-transformed BALB/c 3T3 cells, (b) EAP retains its inhibitory activity in the presence of antibodies against TGF beta and (c) the inhibitory activity did not copurify with TGF beta. Partial characterization of our inhibitory factor suggests that the inhibitory factor is a new tumour-growth-inhibitory factor.
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PMID:Growth suppression of transformed cells by a human placental extract not related to transforming growth factor beta. 203 88

Operative material obtained from patients with lung cancer and precancer, carcinoids, secondary tuberculosis, chronic nonspecific diseases and pulmonary lymphosarcoma was examined immunohistochemically. Expression of the oncogenes was higher in lung carcinoma than in the foci of lung epithelium regeneration, metaplasia and dysplasia. All the oncogenes in precancer and cancer may be divided into two groups by the degree of their expression: oncogenes the activation of which occurs in the same way at certain stages of tumour progression regardless of the lung carcinoma histogenesis and oncogenes expressed at certain stages depending upon the carcinoma histogenesis. The majority of oncogenes studied may be included into the second group (C-myc, ras, sis, src) and only one c-fos into the first group. The oncogenes expression may occur at the precancerous stage and precede the morphological changes in cells and tissues. The expression of some oncogenes (C-myc, sis) takes place not only in the tumour parenchyma but in the cancer stroma as well thus making the immunohistochemical method most reliable that permits one to study a true expression of oncogenes by cancer cells.
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PMID:[The immunohistochemistry of cellular oncogenes in precancer and cancer of the lung]. 228 84

The majority of human lung cancers arise from bronchial epithelial cells. The normal pseudostratified bronchial epithelium is composed of basal, mucous, and ciliated cells. This multi-differentiated epithelium usually responds to xenobiotics and physical injury by undergoing basal cell hyperplasia, mucous cell hyperplasia, and squamous metaplasia. One step of the multistage process of carcinogenesis is thought to involve aberrations in control of the squamous metaplastic processes. Decreased responsiveness to regulators of terminal squamous differentiation may confer a selective clonal expansion advantage to an initiated cell. We studied the effects of endogenous [e.g., transforming growth factor beta 1 (TGF-beta 1) and serum] and exogenous [e.g., 12-O-tetradecanoyl-13-phorbol-acetate (TPA), tobacco smoke condensate, and aldehydes] modifiers of normal human bronchial epithelial (NHBE) cell in a serum-free culture system. NHBE cells are growth inhibited by all of these compounds and induced to undergo squamous differentiation by TGF-beta 1 or TPA. In contrast, lung carcinoma cell lines are relatively resistant to inducers of terminal squamous differentiation which may provide them with a selective growth advantage. Chemical agents and activated protooncogenes (ras,raf,myc) altered the response to endogenous and exogenous inducers of squamous differentiation and caused extended cellular lifespan, aneuploidy, and/or tumorigenicity. The data suggest a close relationship between dysregulation of terminal differentiation pathways and neoplastic transformation of human bronchial epithelial cells.
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PMID:Control of growth and squamous differentiation in normal human bronchial epithelial cells by chemical and biological modifiers and transferred genes. 253 23


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