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Query: UMLS:C0006826 (cancer)
 1,092,456 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Clonal cytogenetic abnormalities found in 30 non-small cell lung carcinomas (NSCLC), including 28 newly diagnosed primary tumor specimens, are summarized. Multiple chromosome alterations were identified in every case, and 19 of 30 tumors had near-triploid or near-tetraploid karyotypes. Polysomy 7 and partial gains of 7p, including 7p11-p13 (site of the EGFR gene), were particularly frequent, occurring alone or in combination in 26 tumors. Recurrent losses involving 1p, 3p, 6q, 9p, 11p, 15p, and 17p (where the TP53 gene is located) were each seen in 16-25 cases. Five tumors exhibited double minutes, which were associated with amplified MYC1 (1 case) and EGFR (1 case), as determined by Southern analysis. The cytogenetic data were compiled from either short term cultures of tumor tissue harvested within 1-9 days (18 cases) or later harvests performed on long term cultures or cell lines (6 cases); in the other 6 cases results were obtained from both short term and long term cultures. Two studies were performed to validate the use of long term culture for cytogenetic analysis of solid lung tumors. First, in order to determine whether cytogenetic results from cultures are representative of the original tumor, the modal chromosome number of 13 specimens placed into culture was compared to the DNA index of the original tumor tissue, as measured by flow cytometry. The DNA indices of the solid tumor biopsies agreed with the degree of aneuploidy observed by cytogenetic analysis in every case. Second, in 6 cases we performed direct comparisons of karyotypes obtained from cells cultured by both methods. Identical chromosome abnormalities were detected in short term cultures and later harvests of the same specimen. Overall, our findings indicate that tumorigenesis in NSCLC is characterized by the accumulation of multiple chromosome alterations. Furthermore, these data demonstrate that recurrent cytogenetic changes can be identified in NSCLC and that detailed karyotypes from long term cultures are relevant to the original tumor. Chromosome abnormalities detected by these techniques may have clinical and biological significance. However, the complex pattern of karyotypic changes seen in newly diagnosed NSCLC emphasizes the need for future investigations of premalignant bronchial lesions in order to identify primary genetic changes important for early detection and intervention in this aggressive neoplasm.
Cancer Res 1992 May 01
PMID:Chromosome abnormalities in human non-small cell lung cancer. 131 34

We have compared the protein tyrosine kinase activities of the chicken epidermal growth factor receptor (chEGFR) and three ErbB proteins to learn whether cancer-activating mutations affect the kinetics of kinase activity. In immune complex assays performed in the presence of 15 mM Mn2+, ErbB proteins and the chEGFR exhibited highly reproducible tyrosine kinase activity. Under these conditions, the ErbB and chEGFR proteins had similar apparent Km [Km(app)] values for ATP. The ErbB proteins appeared to be activated, as they had at least 3-fold-higher relative Vmax(app) for autophosphorylation and approximately 2-fold higher relative Vmax(app) for the phosphorylation of the exogenous substrate TK6 (a bacterially expressed fusion protein containing the C-terminal domain of the human EGFR). The ErbB kinases had both higher Km(app) and higher Vmax(app) for the phosphorylation of the exogenous substrate TK6 than did the chEGFR. The ratios of the Vmax(app) to the Km(app) for TK6 phosphorylation suggested that the ErbB proteins had lower catalytic efficiencies for the exogenous substrate than did the chEGFR. The three tested ErbB proteins had cytoplasmic domain mutations that conferred distinctive disease potentials. These mutations did not affect the kinetics for the phosphorylation of the exogenous substrate TK6. Two of the ErbB proteins contained all of the sites used for autophosphorylation. In these, a mutation that broadened oncogenic potential to endothelial cells caused an additional increase in Vmax(app) for autophosphorylation. Thus, mutations that change the EGFR into an ErbB oncogene cause multiple changes in the kinetics of protein tyrosine kinase activity.
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PMID:Protein tyrosine kinase activities of the epidermal growth factor receptor and ErbB proteins: correlation of oncogenic activation with altered kinetics. 131 48

To document over-expression of proto-oncogenes in tumors, it is necessary to determine the level of expression in the progenitor normal tissue. These studies compare the levels of nuclear transcription of a series of growth-factor related genes and proto-oncogenes in human glioblastoma cell lines with those in three normal glial cell populations. The unusual finding was that levels in the three normal glial cell populations varied considerably for several genes and thus overexpression of a specific gene in a tumor cell when compared to just one normal glial cell population would not necessarily represent overexpression. In this study, we compared the level of 17 genes in 7 tumors to the highest level of each gene found in any of three normal glial cell populations. Over-expression of PDGF-B in 4/7 glioblastoma cell lines, EGFR in 1/7, neu in 1/7 IGF-2 in 1/7 and ros in 2/7 was observed. The variation observed in the normal glial cell populations emphasizes the possibility that the normal glial cell populations represent different glial cell lineages and/or stages of differentiation and that the tumors could have arisen from different normal glial cells. Matching lineages of normal and tumor cells, probably by monoclonal antibody reactions, may be required to accurately define over-expression.
Cancer Lett 1992 Jul 31
PMID:Transcriptional patterns of growth factors and proto-oncogenes in human glioblastomas and normal glial cells. 132 85

To investigate the expression of c-H-ras (p21), c-erb B1 (EGFR) and c-erb B2 (p185) gene products in human bladder cancer, immunohistochemical studies using monoclonal antibodies to these proteins were performed on formaline fixed (within 15 hours)-paraffin sections of tumor tissues from 20 patients with bladder cancer, normal appearing adjacent bladder (non-tumor) tissues from 11 of the 20 patients, and normal bladder tissues from 3 patients who died of non-cancerous diseases as control. p21 Positive staining was demonstrated in the superficial cells of urothelium in 1 of 3 controls, also in 5 of 20 tumor tissues compact cells without vacuole in cells which have an increased nuclear/cytoplasmic ratio. Seven of 11 non-tumor tissues indicated positive staining either in superficial layer only or in whole layers of urothelium, and 1 of the latter group reacted with the monoclonal antibody to human bladder cancer produced in our laboratory. EGFR was found in 5 of 20 tumor tissues and 7 of 11 non-tumor tissues, but not in controls. Most EGFR positive tissues also indicated p21 positivity except in 1 of the tumor tissues. p185 Positive staining was demonstrated in 9 of 20 tumor tissues and 5 of 11 non-tumor tissues, but not in the controls. Furthermore, 5 of 6 tumor tissues from the patients with lymph node metastasis indicated p185 positivity. These results suggest that both p21 and EGFR may have a role in transformation and that p185 has a role in the development of metastasis in some urothelial malignancies.
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PMID:[Expression of c-H-ras, c-erb B1 and c-erb B2 gene products in human bladder cancer]. 135 18

Cytogeneticists first proposed that the karyotypic abnormalities identified on chromosomes 1, 3, 6, 11, 13, 16, 17, and 18 supported a genetic basis for breast cancer. Such abnormal banding patterns, however, may represent either loss-of-function or gain-of-function molecular events. RFLP analyses have since confirmed that 20-60% of primary and spontaneous human breast tumors exhibit allelic losses on these same chromosomes, although the exact genes involved at these chromosomal sites remain largely unknown. Knowledge gained about the Rb-1 and p53 tumor suppressor genes at 13q14 and 17p13 in breast and other human tumors supports the paradigm that for any chromosomal locus, allelic loss associated with a mutation in the remaining tumor allele signifies an involved tumor suppressor gene. Given this paradigm, there are nearly a dozen putative breast tumor suppressor genes under active investigation, with most investigators now focusing on various chromosome 17 loci. Among the known proto-oncogenes found activated in breast cancer, amplification of c-erbB-2 at 17q21 is the most widely studied and clinically significant gain-of-function event uncovered to date, occurring in about 20% of all primary breast tumors. The involvement of this overexpressed membrane receptor has engendered interest in related tyrosine kinase receptors, such as EGFR, IR, and IGF-I-R, as well as their respective ligands, which may be overexpressed in a greater fraction of tumors, contributing to the autocrine and paracrine regulation of breast cancer growth and metastasis. New attention is being given to the potentially oncogenic function of structurally altered nuclear transactivating steroid hormone receptors, such as ER, whose overexpression has long been used to determine endocrine therapy and prognosis for individual breast cancer patients. While c-myc was one of the first known proto-oncogenes to be found amplified and overexpressed in human breast cancers, the actual incidence and clinical significance of its activation remain disputed and in need of further study. Lastly, we can expect greater clarification about the importance of various 11q13 genes found coamplified in nearly 20% of primary breast cancers, and pursuit into the intriguing possibility that a cyclin-encoding gene represents the overexpressed locus of real interest in this amplicon. Virtually all of these important genetic abnormalities identified thus far are associated with but not restricted to human breast cancers. The absence of identifiable molecular defects relating to the tissue specificity of this malignancy must be considered a substantial gap in our basic understanding of breast carcinogenesis.(ABSTRACT TRUNCATED AT 400 WORDS)
Cancer Treat Res 1992
PMID:Activated oncogenes and putative tumor suppressor genes involved in human breast cancers. 136 56

The levels of cell membrane epidermal growth factor receptor EGFR and cytosol (c) and nuclear (n), oestrogen (E) and progesterone (P) receptors (R) were determined in 132 specimens of primary breast cancers. In the tumours of postmenopausal women an inverse significant correlation was demonstrated between the concentrations of EGFR vs. ERc, ERn, and PRc while no such correlation was noted in the tumours of premenopausal women. Premenopausal and postmenopausal EGFR positive tumours (> or = 10 fmol/mg membrane protein) could be regarded as homogenous with respect to the concentration of ER and PR whose mean values were low and without being significantly different. EGFR negative tumours were heterogeneous with respect to the ER and PR concentrations. Postmenopausal EGFR negative (< 10 fmol/mg membrane protein) tumours had evidently higher mean values of ER and PR than premenopausal EGFR negative tumours, but these differences were statistically significant for oestrogen receptors only. The levels of ER and PR of premenopausal EGFR negative tumours were approximated to the corresponding levels of EGFR positive tumours.
Eur J Cancer 1992
PMID:Relations between epidermal growth factor receptor and oestrogen and progesterone receptors in breast cancers of premenopausal and postmenopausal patients in Kuwait. 144 50

Chemoprevention trials in lung and upper aerodigestive tract (UADT) cancer are guided by the field cancerization hypothesis. Inhaled carcinogens place the entire epithelial lining at risk for the development of cancer. The hypothesis is supported by the occurrence of premalignant lesions, such as leukoplakia or squamous metaplasia, and multiple primary tumors within the field. The concept of carcinogenesis as a multistep process suggests the possibility of blocking or reversing the progression to invasive cancer with systemic treatment. A series of ongoing clinical trials will determine the efficacy of retinoid chemoprevention and will attempt to develop intermediate biomarkers. Biomarkers which reliably reflect progression towards cancer could be used to dramatically improve the efficiency of chemoprevention trials and also would aid in screening potential chemoprevention agents. Genomic biomarkers include non-specific estimates of ongoing DNA injury, such as micronuclei, as well as development of aneuploidy and alterations in oncogenes. A class of biomarkers of increasing importance assess proliferation and growth regulation, and include proliferating cell nuclear antigen (PCNA), TGF-beta, EGFR and retinoid receptors. Other markers, such as the blood group antigens, reflect differentiation and may be associated with the development of premalignant lesions. Preliminary data from several of these markers has suggested an association with carcinogenic exposures and premalignant lesions, but none of these markers either alone or in panels have yet been validated as a reliable surrogate for the development of invasive cancer.
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PMID:Intermediate biomarkers in upper aerodigestive tract and lung chemoprevention trials. 146 3

In this study, 3 human pancreatic adenocarcinoma cell lines (PC-1, PC-2 and PC-3) and 3 other human cancer cell lines (adenocarcinoma of lung, LETP; gastric carcinoma, SGL7901; and breast carcinoma, BCP37) were investigated by adding EGF, anti-EGF antiserum and anti-EGFR monoclonal antibody into culture medium. EGF was found to exert a mild stimulating effect on the growth of PC-1 and LETP cells, but had no effect on the other 4 cell lines. Anti-EGF and anti-EGFR antibodies inhibited the proliferation of PC-1, LETP and SGL7901 cells. No significant effect on the other 3 cell lines was seen. By using the Northern blot technique, expression of EGFR mRNA was identified in all 6 cell lines. There were 3 bands (10.5 kb, 5.8 kb and 2.8 kb) of EGFR mRNA in all cell lines except for LETP, in which the 10.5 kb band was absent. The results indicate that the effect of EGF on the growth of cancer cells is very complicated and may involve an unknown regulatory mechanism of cancer cell growth. EGF may exert stimulating or inhibiting effects on cancer cell proliferation, or it may have no effect at all, even though the EGFR gene was expressed in these cell lines.
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PMID:[Effects of EGF, anti-EGF and anti-EGFR antibodies on the growth of human cancer cells]. 147 18

Epidermal growth factor (EGF) and transforming growth factor alpha (TGF alpha) are important keratinocyte mitogens. Their effects are mediated by a cell membrane receptor (EGFR), quantitative and qualitative abnormalities of which may be responsible for deranged keratinocyte proliferation and differentiation. We have therefore examined EGFR expression immunohistochemically in a variety of benign and malignant epithelial neoplasms using monoclonal antibodies to the extracellular and intracellular receptor domains. In benign tumours (virus wart, seborrhoeic keratosis, keratoacanthoma), there was an ordered pattern of EGFR expression. In malignant tumours (basal and squamous cell carcinoma), there was loss of membrane labelling and cytoplasmic accumulation of the receptor. In premalignant proliferations, there was loss of membrane receptor with either absent cytoplasmic EGFR (actinic keratosis) or cytoplasmic receptor accumulation (Bowen's disease). Evidence of truncated receptors was not found. We suggest that dysregulation of the EGFR may be important in the development of cutaneous epithelial malignancies but that grossly abnormal forms of the receptor do not occur.
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PMID:Abnormal expression of epidermal growth factor receptor in cutaneous epithelial tumours. 155 70

Using a panel of somatic cell hybrids that segregate rat chromosomes, the localization of five cancer-related rat genes was determined: (i) two thyroid receptor genes, THRA1/ERBA1 and THRB/ERBA2 on chromosomes 10 and 15 respectively, (ii) two ERBB genes, namely the epidermal growth factor gene (EGFR, also called ERBB1) and the ERBB2 gene (also designated neu) on chromosomes 14 and 10 respectively, and (iii) the retinoblastoma gene, RB1, on chromosome 15. The THRA1/ERBA1 and ERBB2/neu genes are thus included in a synteny group, conserved on rat chromosomes 10 and human chromosome arm 17q.
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PMID:Chromosomal assignment of five cancer-associated rat genes: two thyroid hormone receptor (ERBA) genes, two ERBB genes and the retinoblastoma gene. 167 28


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