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Query: UMLS:C0012872 (DNA marker)
 929 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Malignant melanoma has been documented to display recurring abnormalities of chromosome 6, particularly the long arm (6q). Restriction fragment length polymorphism analysis was used as a molecular genetic approach to examine loci on chromosome 6q for loss of constitutional heterozygosity (LOH). Five DNA markers that recognize restriction fragment length polymorphisms along 6q and one polymorphic DNA marker for 6p were used to screen 20 autologous pairs of tumor DNA and normal DNA to determine the tumor and constitutional genotypes of each patient. LOH on chromosome 6q was identified at 21 of 53 informative loci (40%). Five patients with more than one informative locus had allele losses consistent with the loss of the entire long arm (or of an entire copy) of chromosome 6, while four other patients demonstrated terminal deletions of 6q. The chromosomal region bearing the highest frequency of 6q allelic loss (60%) is defined by the marker loci c-MYB and ESR (6q22-23 and 6q24-27). In contrast to the frequency of 6q loss, LOH was observed at loci on four other chromosomes (1, 11, 16, 17) in only 5% of cases. These results have led us to conclude that the loss of sequences from the long arm of chromosome 6 is a nonrandom and possibly biologically relevant event in human malignant melanoma.
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PMID:Loss of heterozygosity for loci on the long arm of chromosome 6 in human malignant melanoma. 168 May 51

It is now widely accepted that human neoplasms arise as a result of a sequence of mutations affecting the structure of genes involved in growth control. In humans, indirect measurements based on age dependent tumor incidence predict that, on average, the accumulation of 5 to 6 different steps is needed to initiate tumor formation. These mutations do not appear to be random, in that certain neoplasms show prediction for structural aberrations in specific genes. In thyroid tumors, some of gene abnormalities were found. The point mutations of ras oncogenes, predominantly H-ras codon 12, are found in 20-25% of follicular adenomas and papillary carcinomas. Recently, the gene rearrangements of the oncogenes trk and ret were identified in the DNA from papillary carcinomas. About 25% of papillary carcinomas contained an introchromosomal (10q) gene rearrangement involving the tyrosine kinase domain of the ret oncogene with an unknown amino-terminal sequence. The mutations of trk and/or ret were not observed in other thyroid neoplastic phenotypes. In medullary thyroid carcinoma, which is a tumor of the parafollicular, calcitonin-secreting C cell of the thyroid, approximately 20% of patients have autosomal dominant inherited forms. Germ line abnormalities on chromosome 10 are linked to at least one type of genetic medullary thyroid carcinoma (MEN type 2a). In the present time, the person who has the abnormality of gene causing MEN type 2a is able to detect by using DNA marker before the onset of tumor.
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PMID:[Thyroid carcinoma]. 198 98

Molecular genetic studies of tumor-specific allele loss, originally associated primarily with research regarding childhood hereditary cancers such as retinoblastoma and Wilms' tumors, only lately have been recognized as a relatively fast and fruitful way of locating cancer genes on human chromosomes. To date, over 25 different cancers have been tied to a gene (or genes) on a specific chromosome when this method has been used. During the past year alone, this approach has permitted detection of three genes involved in either hereditary or sporadic colorectal cancers. These three genes, located on chromosomes 5q, 17p, and 18q, are believed to belong to the newly described tumor suppressor (or growth suppressor) gene class, whose effects are opposite those of activated cellular oncogenes, which promote uncontrolled cell growth. Present studies, however, have not shown losses of any of these tumor suppressor genes to be correlated with the presence of activated ras genes in colorectal adenomas or carcinomas. During progression from adenoma to carcinoma, ras gene mutations and 5q allelic deletions are likely to be earlier events, whereas allelic losses from chromosomes 18q and 17p seem to occur more often in advanced tumors. Involvement of the genes on 5q (FAP) and 18q (Lynch syndrome II) in hereditary colon cancer syndromes is supported by linkage studies, but their respective roles (as well as that of the gene on 17p) in familial and sporadic colorectal cancer remain to be precisely defined. Probable isolation of these three genes by molecular cloning within the next few years will help elucidate their specific biologic functions. It will also permit early detection, and thus prevention, of some familial colon cancers (such as FAP), and possibly allow DNA marker-based separation of different colon cancer subtypes of similar histologic appearance.
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PMID:Molecular genetic studies of colon cancer. 264 66

A molecular genetic approach employing polymorphic DNA markers has been used to investigate the role of chromosomal aberrations in meningioma, one of the most common tumors of the human nervous system. Comparison of the alleles detected by DNA markers in tumor DNA versus DNA from normal tissue revealed chromosomal alterations present in primary surgical specimens. In agreement with cytogenetic studies of cultured meningiomas, the most frequent alteration detected was loss of heterozygosity on chromosome 22. Forty of 51 patients were constitutionally heterozygous for at least one chromosome 22 DNA marker. Seventeen of the 40 constitutionally heterozygotic patients (43%) displayed hemizygosity for the corresponding marker in their meningioma tumor tissues. Loss of heterozygosity was also detected at a significantly lower frequency for markers on several other autosomes. In view of the striking association between acoustic neuroma and meningioma in bilateral acoustic neurofibromatosis and the discovery that acoustic neuromas display specific loss of genes on chromosome 22, we propose that a common mechanism involving chromosome 22 is operative in the development of both tumor types. Fine-structure mapping to reveal partial deletions in meningiomas may provide the means to clone and characterize a gene (or genes) of importance for tumorigenesis in this and possibly other clinically associated tumors of the human nervous system.
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PMID:Molecular genetic approach to human meningioma: loss of genes on chromosome 22. 303 50

Rhabdoid tumor of the kidney (RTK) is associated with tumors of the central nervous system (CNS) in approximately 15% of cases. We describe the clinical features, histologic and cytogenetic findings, and molecular analysis of renal and CNS tumors from the same patient. The histology of the renal tumor was consistent with rhabdoid tumor. The CNS tumor was a primitive neuroectodermal tumor (PNET). The karyotype of the RTK was normal male. The PNET of the brain demonstrated monosomy 22 as the only cytogenetic abnormality, similar to reported cases of malignant rhabdoid tumor of the brain, but dissimilar to nonrandom cytogenetic findings in other CNS PNETs. Molecular cytogenetic and DNA marker studies confirmed loss of chromosome 22 in this patient's brain tumor. DNA allelotyping showed retention of both parental chromosome 22 alleles in the RTK and loss of the maternal allele in the PNET. Evaluation of additional RTKs and brain tumors occurring in the same patient may provide insight into the origins and relationships of these enigmatic tumors.
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PMID:Rhabdoid tumor of the kidney with primitive neuroectodermal tumor of the central nervous system: associated tumors with different histologic, cytogenetic, and molecular findings. 753 Apr 83

Multiple endocrine neoplasia types 2A and 2B (MEN 2A and MEN 2B) and familial medullary thyroid carcinoma (FMTC) are dominantly inherited cancers that have in common the clinical feature of medullary thyroid carcinoma (MTC). We have performed both genomic long-range restriction mapping and yeast artificial chromosome (YAC) contig assembly and restriction mapping to establish physical linkage, order, and distances between six loci in 10q11.2 near the genes responsible for these hereditary cancers. RET, D10S94, D10S182, and D10S102 have been mapped in genomic DNA. RET, D10S94, D10S182, D10F38S3, and the 10q11.2 sequences detected by DNA marker DM124 are encompassed by a 1-Mb YAC contig. Six physically linked loci are within 1.4 Mb and have an order and orientation of 10cen, D10F38S3, DM124, RET, D10S94, D10S182, D10S102, 10qter. Mutations in the RET proto-oncogene have recently been demonstrated to be associated with MEN 2A and FMTC. RET is located within a genetically defined MEN2A candidate interval between D10S141 and D10S94; MEN2B has been mapped to a larger, overlapping region between D10S141 and a more distal locus, RBP3. Both our genomic physical map and our YAC contig span the entire MEN2A candidate region and overlap with that of MEN2B. These maps will facilitate the identification of genes that can be considered candidates for MEN2B and the identification of tumor-specific alterations important in sporadic MTC.
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PMID:Genomic and yeast artificial chromosome long-range physical maps linking six loci in 10q11.2 and spanning the multiple endocrine neoplasia type 2A (MEN2A) region. 790 24

Apoptosis, a form of cell death ("programmed" cell death) in which the nucleus and cytoplasm shrink and often fragment, serves to eliminate excessive or unwanted cells during remodeling of embryonic tissues, during organ involution, and in tumor regression. In acute pathological states, such as ischemia, the cells tend to swell and lyse--a process called necrosis. We hypothesize that the delayed neural death clinically associated with hypoxia may, in part, represent apoptosis. A tissue culture model of 24 hours of hypoxia was employed using sympathetic neurons. Pretreatment with an endonuclease inhibitor (aurintricarboxylic acid) decreased cell death by 53%, depolarizing conditions (55 mM potassium chloride) decreased cell death by 33%, and an RNA synthesis inhibitor (actinomycin D) by 26% (all have been shown to prevent apoptosis). Pretreatment with antisense c-myc had no effect. Fluorescent staining with propidium iodide (a DNA marker) demonstrated chromatin condensation and agarose gel electrophoresis demonstrated a DNA "ladder." These data suggest that apoptosis may play a role in hypoxic cell death and that in this paradigm, expression of c-myc is unnecessary. This would suggest a new approach to our understanding of hypoxia and open new strategies to lessen neuronal damage secondary to this process.
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PMID:Evidence for hypoxia-induced, programmed cell death of cultured neurons. 799 72

Cytogenetic and molecular analyses of human breast cancer cells have identified consistent losses of specific chromosomal regions in these tumors, suggesting that such regions harbor tumor suppressor genes whose homozygous loss or inactivation directly contributes to tumorigenesis. To date, deletions of chromosome 8 sequences have been described infrequently and only in low percentages of breast carcinomas. We report the identification of a new DNA marker on chromosome 8p that is deleted in 6 (75%) of 8 breast carcinoma cell lines and in 1 primary breast carcinoma examined. No deletion of this marker was detected in any normal or nonbreast carcinoma cell lines analyzed. Southern blot and fluorescence in situ hybridization studies indicate that this clone maps to chromosome 8 between bands p12 and p21. These observations suggest that a new gene, whose loss or inactivation may foster breast carcinoma tumorigenesis, may reside in this chromosome 8p region.
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PMID:Loss of chromosome 8p sequences in human breast carcinoma cell lines. 807 45

Specific tumor-associated rearrangements involving the regions 11p13 and 11p15 have been extensively documented. However, cytogenetic definition of the breakpoints occurring at the boundaries of these two regions was not precise enough to correlate with the molecular data. Using probes corresponding to the genes coding for MYOD1, CTSD, LDHA, and RBTN1 and to the anonymous sequence D11S776, we have reassessed the breakpoints of three hybrids (J1.10, BID7, and NYX3.1) and confirmed the localization or more precisely mapped these four genes and the anonymous DNA marker on different subregions of 11pter-->p13, including the smallest region of 11p15.5 duplicated in a patient with Beckwith-Wiedemann syndrome.
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PMID:Reassessment of breakpoints in chromosome 11p15. 842 57

Sixty-three non-small cell lung carcinomas (NSCLCs) and 20 small cell lung carcinomas (SCLCs) were examined for loss of heterozygosity (LOH) on chromosome 2. Fifteen highly polymorphic dinucleotide markers spanning both the short and long arms of chromosome 2 were selected for a polymerase chain reaction (PCR)-based fine mapping. They included a DNA marker localized in the homozygously deleted region at 2q33, which we previously identified in an SCLC cell line. LOH on chromosome arm 2q was detected in 23/63 (37%) of NSCLC and 6/20 (30%) of SCLC, while LOH on 2p was observed in 14/56 (25%) and 4/17 (24%), respectively. There were two commonly deleted regions mapped to 2q32-q37 and 2p16-pter, and the homozygously deleted region at 2q33 was in the commonly deleted region on 2q. In NSCLC, the incidence of LOH on 2p and 2q was significantly higher in brain metastases than in primary tumors (P = 0.005 and 0.001, respectively). In addition, LOH on chromosome arm 2q occurred more frequently in moderately/poorly differentiated tumors than in well-differentiated tumors (P = 0.046). These results suggested that inactivation of tumor suppressor genes on chromosome 2 is involved in the phenotypic alterations of NSCLC cells into more aggressive ones.
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PMID:Deletion mapping of chromosome 2 in human lung carcinoma. 881 58


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