Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0149925 (small cell lung cancer)
 6,491 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Typical carcinoid, atypical carcinoid, and small cell lung cancer (SCLC) fall within the spectrum of neuroendocrine lung neoplasms. This paper investigates the immunohistochemical expression of the products of tumour suppressor genes p53 and retinoblastoma (RB), together with proliferation (PCNA and Ki67) and neuroendocrine differentiation markers, in 14 typical carcinoids, ten atypical carcinoids, four borderline atypical carcinoid/SCLC, and 11 SCLC. We demonstrated that the phosphoprotein p53 and RB product can be immunolocalized on routine histological material. p53 protein was absent in all typical and atypical carcinoids, while it was abnormally expressed in eight SCLC and one borderline case. RB product was detected in all typical carcinoids and in two atypical carcinoids, while it was consistently absent in the other cases. PCNA-labelled cells were less than 4 per cent in typical carcinoids, about 40 per cent in atypical carcinoids, and over 70 per cent in SCLC. PCNA labelling index discriminates between typical and atypical carcinoids. Neuroendocrine differentiation was evaluated by a semi-quantitative method: a mean score value was obtained, which was high in typical carcinoids, intermediate in atypical carcinoids, and low in SCLC. Our data was obtained, which was high in typical carcinoids, intermediate in atypical carcinoids, and low in SCLC. Our data show that the decrease in neuroendocrine features from typical carcinoid to SCLC is paralleled by an increase in proliferative activity and by an altered expression of tumour suppressor gene products. The above findings have diagnostic relevance.
 ...
PMID:Tumour suppressor gene products, proliferation, and differentiation markers in lung neuroendocrine neoplasms. 135 31

Studies of mutant genotypes of the retinoblastoma susceptibility gene (RB1) in different solid tumors have mainly been concentrated on the demonstration of loss of heterozygosity (LOH) at both internal and external polymorphic sites. One reason for this is the complex organization of the gene. The p105RB protein has been shown to interact with both DNA and regulatory cellular proteins and oncoproteins. The amino acids encoded by exon 21 are implicated in several of these interactions. Both point mutations and intragenic deletions involving exon 21 have previously been reported in human tumors. We have examined RB1 exon 21 from a number of human tumor types where significant LOH in or around the RB1 gene has been reported. DNA from 78 primary tumors was amplified using the polymerase chain reaction (PCR) with primers covering exon 21, followed by constant denaturant gel electrophoresis (CDGE). The 78 tumors included 11 breast carcinomas, 30 nonsmall cell lung carcinomas, 6 colon carcinomas, and 31 sarcomas. The small cell lung cancer cell line NCI-H209, previously shown to harbour a point mutation in codon 706: TGT- greater than TTT (Cys- greater than Phe), was detected using CDGE. Apart from this control mutant cell line, we did not detect any mutations in the examined region in any of the tumors.
 ...
PMID:No alterations in exon 21 of the RB1 gene in sarcomas and carcinomas of the breast, colon, and lung. 138 57

Major new insights into carcinogenesis have come from recent advances in cellular and molecular biology. The concept of oncogenes provides a simple explanation for how agents as diverse as radiation, chemicals or retroviruses can induce tumors that are indistinguishable one from another. Oncogenes may be activated by a point mutation, by a chromosome translocation, or by amplification. Ionizing radiations are efficient at the first two mechanisms. While oncogenes are frequently associated with leukemias and lymphomas, they are associated with only 10 to 15% of human solid cancers. The importance of the loss of suppressor genes was suggested first from studies with human-hamster hybrid cells, but has since been shown to be of importance in an increasing number of human solid tumors, from rare tumors such as retinoblastoma to more common tumors such as small cell lung cancer and colorectal cancer. The mechanism of somatic homozygosity clearly involves several steps, some of which, such as a deletion, could be readily produced by ionizing radiation. The multi-step nature of carcinogenesis can be demonstrated in the petri dish, where the transfection of multiple oncogenes is required to transform normal cells from short-term explants. It can be shown, too, in colorectal cancer in the human, where the activation of an oncogene and the loss of more than one suppressor gene may be involved in the progression from normal epithelium to a frank malignancy.
 ...
PMID:The molecular biology of radiation carcinogenesis. 181 75

Inactivation of the retinoblastoma gene (RB gene) is associated with the development of several human malignancies including retinoblastomas, some osteo- and soft tissue sarcomas, small cell lung cancer, and possibly breast and bladder cancers. To our knowledge, this gene has not been evaluated in human germ-cell malignancies. In this study 67 primary testicular germ-cell tumors and 4 testicular non-germ-cell malignancies were examined to determine the prevalence and nature of RB gene alterations. Decreased expression of RB gene mRNA was found in all testicular germ-cell tumors (both seminomas and nonseminomas) examined. The RB protein could not be detected by immunohistochemical analysis in the undifferentiated cells of any germ-cell tumors whereas the differentiated malignant cells present in 14/15 teratocarcinomas expressed the protein. No gross alterations of the RB gene were found at DNA level in any of the examined specimens. This and the presence of the RB protein in the more differentiated tumor cells of teratocarcinomas suggest that changes in transcript levels rather than mutation(s) of the gene may be responsible for the absent or decreased RB expression in human germ-cell tumors. To date studies on the mechanism of RB regulation have demonstrated that it occurs at the protein level by phosphorylation of the p105 gene product. The findings presented here indicate that additional regulation might occur at the transcript level.
 ...
PMID:Correlation between retinoblastoma gene expression and differentiation in human testicular tumors. 186 90

Over the past 200 years, a bewildering array of chemical, physical, and viral agents has been identified that can cause cancer, but the mechanisms involved are only now becoming clear. In the leukemias and lymphomas, it appears that the activation of cellular oncogenes is important. The genes involved are present in all normal cells and are often associated with cell growth and regulation. When activated, they act in a dominant fashion to cause a cell to express the malignant phenotype. There is increasing evidence that in solid tumors, a more important mechanism may be the loss of a suppressor gene. The classic example is retinoblastoma, in which the retinoblastoma gene has been cloned and is also found to be associated with several other common cancers including sarcomas and small cell lung cancer. It is likely to be one of a family of such genes. It may well be that the activation of one or more oncogenes or the loss of one or more suppressor genes, or both, is required for a tumor to progress from initiation through promotion to a metastasizing malignancy.
 ...
PMID:From chimney sweeps to oncogenes: the quest for the causes of cancer. 201 68

Karyotypic and molecular genetic evidence has indicated that deletion or rearrangement of both chromosomes 3 and 13 may be important in the pathology of human small cell lung cancer (SCLC). The retinoblastoma susceptibility gene, RB, on chromosome 13 band q14, has previously been shown to be altered in SCLC [J. W. Harbour et al., Science (Wash. DC), 241: 353-357, 1988; J. Yokota et al., Oncogene, 3: 471-475, 1988]. Our studies of 26 SCLC tumor and normal DNA samples indicate that 6 of 6 patients whose normal cell DNA was heterozygous for an RB restriction fragment length polymorphism have lost one of the two alleles in their tumor DNA. Consistent with other studies, we find 2 of 26 tumors with homozygous deletions within the RB gene. Of 13 SCLC cell lines examined, only 3 expressed greater than trace amounts of RB mRNA. RB protein was detected in 2 of 14 SCLC cell lines examined, unlike the results of Yokota et al. (Oncogene, 3: 471-475, 1988) which showed no RB protein in any of the 9 cell lines they examined. Only unphosphorylated RB protein was detected in SCLC cell line H209, suggesting that the RB protein may be inactivated by a novel mechanism in this cell line. These data suggest that inactivation of the RB gene is a frequent if not universal event in SCLC.
 ...
PMID:Altered structure and expression of the human retinoblastoma susceptibility gene in small cell lung cancer. 215 70

The putative retinoblastoma gene (Rb) is a tumor suppressor gene which is believed to cause retinoblastomas when both alleles are inactivated, leading to lack of the encoded Mr 110,000-116,000 phosphoprotein. Inactivation of the Rb gene has also been found in several other tumor types, including small cell lung cancer (SCLC). Absence of the 4.7 kilobase mRNA has been found to be frequent in SCLC, and it has been reported that the Rb Mr 110,000-116,000 protein product is always absent, even in tumors expressing Rb mRNA. Using Western blotting technique with a monoclonal antibody directed against the Rb protein, we investigated the expression of the Mr 110,000-116,000 Rb protein in SCLC tumors grown as xenografts in nude mice and/or as cell lines. Rb messenger RNA expression was determined by Northern blotting, and gross structural gene alterations were investigated by Southern blotting. Tumors established from 23 patients were studied. Seven of the tumors did not express Rb protein, whereas expression was detectable in 13. Three tumors were not investigated for protein expression. Only two tumors expressed Rb mRNA without detectable Rb protein expression. Gross DNA alterations were found in four tumors, of which only one expressed Rb mRNA. Our results demonstrated frequent absence of Rb mRNA and protein in SCLC, but apparently normal Rb mRNA and protein were both expressed in more than one-half of the tumors.
 ...
PMID:Abnormalities in structure and expression of the retinoblastoma gene in small cell lung cancer cell lines and xenografts in nude mice. 216 52

Five hundred and fifty two bone marrow (BM) specimens (497 aspirates, 55 biopsies) from 518 patients with nonhaematological malignancies were examined to determine the frequency of metastatic deposits. BM involvement was highest in neuroblastoma (9/14), prostate cancer (2/4), retinoblastoma (3/7), Ewing's sarcoma (14/47), rhabdomyosarcoma (5/20) and small cell carcinoma of lung (3/18). BM aspiration smears were adequate in paediatric tumours (neuroblastoma, retinoblastoma, rhabdomyosarcoma) while BM biopsies were most useful in patients with Ewing's sarcoma, prostate cancer and small cell lung cancer. We conclude that BM is an easy investigation in the diagnosis and staging of nonhaematological cancers.
 ...
PMID:Frequency of bone marrow involvement in non-haematological malignancies. 224 93

The gene predisposing to retinoblastoma, RB1, has been mapped to 13q14 and a cDNA clone has been isolated. Alterations of this chromosomal region are found not only in retinoblastoma, but in other tumor types including bone and soft tissue sarcomas, gastric tumors, small cell lung cancer, hematologic malignancies, rhabdomyosarcoma, and breast cancer. Genetic alterations implicating RB1 in some of these cancers have been observed. A long-range, overlapping restriction map around RB1 has been derived to provide a basis for study of rearrangements in tumors. Putative CpG islands closely linked to RB1 were identified, the effect of methylation was investigated, and RB1 transcriptional direction was determined. Using data in the literature, the map was oriented with respect to the centromere and it was determined that the distance between esterase D, a nearby gene, and RB1 was greater than 200 kb.
 ...
PMID:A physical map around the retinoblastoma gene. 230 71

A deletion involving chromosome 3p (14-23) characteristically occurs in small cell lung cancer (SCLC). Reduction to homozygosity, rather than complete loss, is typically observed for genes in the deleted region. Lack of expression for genes encoded by this region, implying inactivation of all alleles, has not been previously described. We have examined the expression of aminoacylase-1 (ACY-1), encoded by chromosome 3p21, using both an electrophoretic activity assay and a monoclonal antibody-based ELISA. A variety of human tissues, including lung, brain, liver, kidney, heart, adrenal medulla, and erythrocytes have previously been tested for ACY-1 activity and antigen; all but erythrocytes are positive. Thus, ACY-1 is expressed in all nucleated human cells examined to date. ACY-1 was undetectable in a significant number of SCLC cell lines (4/29) and tumors (1/8), but not in non-small cell lung cancer (NSCLC) cell lines (0/19) or tumors (0/9), nor in a variety of other human cell lines (0/15) or colon tumors (0/8). In addition, reduced (approximately 10% of normal) ACY-1 expression was common in SCLC cell lines (14/29) and tumors (3/8), but not in NSCLC cell lines (1/19) or tumors (0/9), nor in other human cell lines (0/15) or colon tumors (0/8). Thus, low or undetectable ACY-1 expression is highly specific for SCLC and occurs in both cell lines and tumor tissue. The finding of undetectable ACY-1 expression in SCLC supports the hypothesis that inactivation of all alleles of specific chromosome 3p genes occurs in a SCLC in a fashion analogous to Rb gene inactivation in retinoblastoma, and suggests that the structural gene for ACY-1 may be closely linked to a putative SCLC tumor suppressor gene.
 ...
PMID:Lack of expression of aminoacylase-1 in small cell lung cancer. Evidence for inactivation of genes encoded by chromosome 3p. 254 83


1 2 3 4 5 Next >>