UMLS:C0684249 - FACTA Search

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

In recent years, a group of new prognostic factors have been added to the list of well-known clinical prognostic factors of non-small cell lung cancer. Among these are mutations in the K-ras oncogene, abnormalities in p53, the presence of N-CAM expression as measured by Mab immunostaining and elevated serum levels of NSE. These factors have provided important clinical insights into the biology of lung cancer and prospective studies using these biomarkers are now warranted to provide further important clues about their potential significance in treatment selection of patients.
Lung Cancer 1995 Apr
PMID:Prognostic factors in NSCLC. Recent experiences. 755 31

The observation that the proteins encoded by ras genes play a central role in the signalling pathways used by cells to respond to growth factors and the fact that mutated ras proteins are constantly promoting cell division have led to a PCR-based hunt for additional clinical information. In the present study, K-ras analysis draws the following conclusions: (1) K-ras point mutation frequency was higher in the surgery group (10 of 24 patients) than in the chemotherapy-surgery group (3 of 20 patients). (2) Mutated K-ras was predominantly observed at codon 12 but five mutations appeared at codon 61. (3) Mutations were identified in the squamous cell carcinoma histological NSCLC subtype except in four cases corresponding to adenocarcinoma. (4) A multifarious pattern of substitutions, especially at codon 12, were noted with aspartic K 12 substitutions more prone to develop bone metastases. (5) Although a genotypic K-ras classification of NSCLC may not yet be formulated, our accumulated data (unpublished) suggest a trend toward it. (6) Patients with mutated K-ras tumors in the surgery group had no different survival than those with normal K-ras. However our pooled data as well as other authors' results assert that mutated K-ras constitute an additional prognostic datum that deserves to be included together with TNM classification. In the design of new preoperative (neoadjuvant) chemotherapy trials, stratification of tumors by K-ras status deserves to be further investigated in order to correlate with response, relapse and survival. Mutated K-ras genotype merits further research. Finally, the paradigm of uneven histological distribution and mutated K-ras spectra among researchers should serve as a stimulus to search for further contributions in this field.
Lung Cancer 1995 Apr
PMID:Mutated K-ras gene analysis in a randomized trial of preoperative chemotherapy plus surgery versus surgery in stage IIIA non-small cell lung cancer. 755 35

This paper reviews mutational activation of ras oncogenes and inactivation of the p53 tumor suppressor gene in human lung cancer. We discuss the frequency, type, and location of mutations in these genes in relation to known etiological factors for lung cancer. The most studied examples of these are exposure to tobacco smoke, and to radon and asbestos fibers at work. We summarize data from our laboratory on K-ras and p53 mutations in fresh tissue samples from patients with resected primary lung carcinoma whose smoking and occupational histories were known. Most of the tumors examined were histologically non-small cell carcinoma (NSCLC), mainly of the squamous cell carcinoma and adenocarcinoma types. We compare the prevalence and nature of mutations in the two histological types of NSCLC.
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PMID:p53 and ras gene mutations in lung cancer: implications for smoking and occupational exposures. 762 Sep 45

K-ras gene point mutation is a highly frequent event in human malignancy. About one third of non-small cell lung cancer (NSCLC) patients harbor K-ras gene point mutational activations. This study investigates the prevalence of K-ras mutation in autopsy tumors with NSCLC, and the correlation of K-ras gene point mutations between primary tumors and metastases in NSCLC. Formalin-fixed, paraffin-embedded tissue sections of 15 primary lung tumors and their metastases, (obtained from autopsy), were examined for the presence of point mutations in K-ras gene codon 12, 13 and 61 by oligodeoxynucleotide hybridization analysis of DNA fragments, amplified by polymerase chain reaction (PCR). K-ras gene point mutations were detected in five cases of lung carcinoma, of which four were adenocarcinomas and one was squamous cell carcinoma. In each of these cases, identical K-ras gene mutations were found in the DNA of both the primary tumor and its corresponding distant metastases. Activating K-ras base-substitutions correlate well between the primary tumor and its corresponding metastases in NSCLC. In the negative cases where no K-ras mutation was found in the primary tumors, no newly acquired K-ras mutation appeared in the metastases. Our study indicates that K-ras point mutation serves as a stable tumor marker in NSCLC.
Lung Cancer 1994 Jul
PMID:K-ras gene point mutation: a stable tumor marker in non-small cell lung carcinoma. 808 2

A retroviral vector system was developed to transduce a K-ras antisense construct efficiently into human cancer cells. A 2-kb fragment of K-ras gene DNA in antisense orientation was linked to a beta-actin promoter and inserted into retroviral vector LNSX in two different orientations. The constructs were transfected into amphotropic packaging cell line GP+envAm12 followed by alternating transduction between the ecotropic packaging cell line psi-2 and GP+envAm12. Titers up to 9.7 x 10(7) colony-forming units (cfu)/ml were achieved without detectable replication-competent virus. The human large cell lung carcinoma cell line H460a, which has a homozygous codon 61 K-ras mutation, was transduced with an efficiency of 95% after five to seven repeated transductions. DNA polymerase chain reaction (PCR) and genomic DNA Southern blot analysis showed that the retroviral construct was integrated into the genome of H460a cells. K-ras antisense RNA expression was detected in the cells by Northern analysis, slot blot hybridization, and reverse transcriptase-PCR. Translation of the mutated K-ras p21 protein RNA was specifically inhibited, whereas expression of other p21 species was unchanged. Proliferation of H460a cells was suppressed 10-fold following transduction by the antisense construct. Colony formation in soft agarose and tumorigenicity in an orthotopic lung cancer model in nu/nu mice were dramatically reduced in H460a cells expressing antisense K-ras. We conclude that an antisense construct for K-ras can be expressed effectively in a retroviral vector that can efficiently transduce human cancer cells.
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PMID:Retroviral vector-mediated transduction of K-ras antisense RNA into human lung cancer cells inhibits expression of the malignant phenotype. 839 92

An orthotopic human lung cancer model in nu/nu mice was used to study the effect of an antisense K-ras (AS-K-ras) retroviral construct on tumor growth in vivo. A 2-kilobase genomic AS-K-ras DNA fragment linked to a beta-actin promoter was cloned into the LNSX retroviral vector. The recombinant construct was packaged into GP+envAm12 cells and titers greater than 10(6) colony-forming units/ml were obtained. Irradiated (350 cGy) nu/nu mice were first inoculated intratracheally with 10(5) H460a human large cell lung carcinoma cells which have a codon 61 mutation of the K-ras oncogene. Three days later they received intratracheal instillation of viral supernatant (5 x 10(6) colony-forming units/ml) from either LNSX, LNSX-AS-K-ras, LNSX-sense-K-ras producer cells, or medium daily for 3 days. At autopsy, 30 days after tumor cell inoculation, 90% of the control mice had tumors whereas 87% of mice treated with the LNSX-AS-K-ras viral supernatant were free of tumors. The efficacy of the viral supernatant was dose dependent. Intratracheal administration of retroviral LNSX-AS-K-ras supernatant prevents the growth of human lung cancer cells implanted orthotopically in nu/nu mice.
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PMID:Prevention of orthotopic human lung cancer growth by intratracheal instillation of a retroviral antisense K-ras construct. 846 90

Neuroendocrine tumors of lung, including typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC), and small cell lung carcinoma (SCLC) constitute a spectrum of malignancies in which the pathologist at times has difficulty in discerning tumor subtype and aggressiveness in a reproducible fashion. Therefore, 59 primary neuroendocrine lung tumors including 10 TCs, 26 ACs, 15 LCNECs, and 8 SCLCs were selected from cases collected from 1976 to 1988 and immunostained for p53 protein. All of these tumors were also genotyped for specific point mutational damage affecting p53 (exons 5, 7, and 8; with ACs additionally sequenced for p53 exon 6); 13 tumors for K-ras-2 (exon 1); and 31 tumors for c-raf-1 (exon 15) growth-regulatory genes. Genotyping was performed on topographically selected, minute tumor samples removed from unstained formalin-fixed, paraffin-embedded tissue sections (topographic genotyping) using polymerase chain reaction and direct sequencing. The distribution of p53 immunohistochemical staining had four patterns: negative in TCs, one-half of ACs, 3 of 15 LCNECs, and 1 of 8 SCLCs; less than 10% but more than five tumor cells per 10 high power fields (focal) in a subset (7 of 26) of aggressive ACs; 10 to 49% of tumor cells (patchy) in a subset (6 of 26) of ACs with a higher grade of aggressiveness; and 50 to 100% of tumor cells (diffuse), exclusively seen in LCNECs (12 of 15) and SCLCs (7 of 8). Three patterns of immunohistochemical staining intensity of p53 protein were seen: negative, weak or mild, and moderate to marked. SCLCs and LCNECs accounted for cases of moderate to marked staining and were the only ones to have mutations in p53 exons 5, 7, or 8. No mutations were found in AC and TC, showing absent to weak staining and no staining, respectively. The difference in distribution and staining intensities between LCNEC and SCLC compared with AC and TC was statistically significant (P < 0.001). Patients having AC with patchy p53 immunostaining usually had survival limited to 3 years, whereas those having AC with focal p53 immunostaining subsequently developed metastatic or recurrence of AC disease (P < 0.05). The absence of point mutations in cases with patchy or focal immunostaining suggests increased expression of wild-type p53 tumor suppressor protein likely in response to growth deregulation in a more aggressive subtype of AC. A novel hypothesis is presented in regard to these findings. K-ras-2 and c-raf-1 gene sequence analysis showed no evidence of point mutational change in any of the tumors studied. The TC and AC categories are therefore genetically distinct from the higher grade neuroendocrine SCLC and LCNEC. Immunohistochemistry for p53 on AC lung tumors may be helpful to delineate cases at higher risk for aggressive behavior. Additionally, although LCNEC is categorized as a non-small-cell carcinoma, it is more akin genetically and immunohistochemically to SCLC.
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PMID:Analysis of p53, K-ras-2, and C-raf-1 in pulmonary neuroendocrine tumors. Correlation with histological subtype and clinical outcome. 862 22

Induction (neoadjuvant) chemotherapy has become an accepted treatment for stage IIIA (T1-3N2M0) non-small cell lung cancer. In two recent randomized trials, neoadjuvant chemotherapy plus surgery gave an increase in median survival at least fivefold greater than surgery alone. The Spanish Lung Cancer Group trial of preoperative chemotherapy, in which the cisplatin dose was randomized to either 50 mg/m2 or 100 mg/m2 plus 3 g/m2 ifosfamide and 6 mg/m2 mitomycin, examines the effect of K-ras gene mutations on tumor response and survival. Patients whose tumors contain K-ras gene mutations are more likely to develop distant metastases and have lower median survival than patients without such mutations. Microsatellite instability seems to be a frequent mechanism of genetic aberrations. Knowledge about these genetic alterations could have prognostic importance and may identify the patients who should receive the most aggressive additional treatment.
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PMID:The role of induction (neoadjuvant) chemotherapy in stage IIIA NSCLC. 863 84

In situ PCR is a new technique for the localization of low copy number sequences. We report here a method for the in situ visualization of a point mutation in K-ras codon 12 by indirect in situ PCR. Twenty-five primers were examined to select mutant-specific primers. Harvested cell lines were fixed and suspended in PCR mixture. Forty cycles of PCR in cell suspension was performed in a thermal cycler using a hot start method. Cells were cytocentrifuged onto slides, and post-fixation was performed. The specimens on the slides were then hybridized with a digoxigenin-labeled probe, followed by color reaction. Both Calu-1 (mutated: TGT) and NCI-H460 (wild type: GGT) cells had strong hybridization signals in the nuclei with general primers. But with mutant-specific primers, only Calu-1 cells had hybridization signals. No signal was observed without primers or Taq DNA polymerase. Southern blotting of the same preparation confirmed desired amplification. We also applied direct in situ PCR, but this method failed to detect the point mutation. We conclude that our indirect in situ PCR method shows the feasibility of in situ identification of single cells carrying point mutations.
Lung Cancer 1997 Jul
PMID:Detection of K-ras point mutation by in situ PCR in cell suspensions: comparison of the indirect and direct methods. 923 54

Previous studies have identified and characterized both murine in vivo and human in vitro T cell responses reflecting specific mutations in the ras proto-oncogenes at codon 12, 13, or 61. In an attempt to determine whether peptide epitopes reflecting point mutations in the ras oncogenes are immunogenic in humans for the production of CD4+ and/or CD8+ T cell responses, a phase I clinical trial was initiated in metastatic carcinoma patients whose primary tumors harbor mutations in the K-ras proto-oncogenes at codon 12. The peptides used here as immunogens, which were administered in Detox adjuvant, spanned the ras sequence 5-17 and reflected the amino acid substitution of glycine (Gly) at position 12 to aspartic acid (Asp), cysteine (Cys), or valine (Val). Three of eight evaluable patients have demonstrated peptide-specific cell-mediated immunity, as determined by the production of T cell lines resulting from the vaccination. First, an antigen (Ag)-specific, major histocompatibility complex (MHC) class II (DP)-restricted CD4+ T cell line was established in vitro from postvaccination lymphocytes of a non-small cell lung carcinoma patient whose primary tumor contained a Cys12 mutation when cultured on the immunizing peptide. Moreover, CD4+ proliferation was inducible against the corresponding mutant K-ras protein, suggesting productive T cell receptor recognition of exogenously processed Ag. Second, an Ag-specific, MHC class I (HLA-A2)-restricted CD8+ cytotoxic T lymphocyte (CTL) line was established in vitro from postvaccination lymphocytes of a colon carcinoma patient whose primary tumor contained an Asp12 mutation. To that end, a 10-mer peptide, nested within the 13-mer immunizing peptide, was identified [i.e., ras5-14(Asp12)], which was shown to bind to HLA-A2 and display specific functional capacity for expansion of the in vivo primed CD8+ CTL precursors. Third, both Ag-specific, MHC class II (DQ)-restricted CD4+ and MHC class I-restricted (HLA-A2) CD8+ T cell lines were generated from a single patient with duodenal carcinoma whose primary tumor contained a Val12 mutation when cultured on the immunizing 13-mer peptide or a nested 10-mer peptide [i.e., ras5-14(Val12)], respectively. Evidence is thus provided that vaccination with mutant ras oncogene peptides in adjuvant may induce specific anti-ras cellular immune responses, with no detectable cross-reactivity toward normal proto-ras sequences. Moreover, we have identified for the first time human HLA-A2-restricted, CD8+ CTL epitopes reflecting specific point mutations in the K-ras oncogenes at codon 12 which, in concert with the activation of the CD4+ T cell response, may have important implications for both active and passive immunotherapies in selected cancer patients.
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PMID:Generation of stable CD4+ and CD8+ T cell lines from patients immunized with ras oncogene-derived peptides reflecting codon 12 mutations. 951 98

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