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Concomitant loss of chromosome 3 and whole arm losses and gains of chromosome 1, 6, or 8 in metastasizing primary uveal melanoma.

PURPOSE: To elucidate the genetic differences between metastasizing and nonmetastasizing primary tumors, uveal melanoma samples were screened for DNA copy number alterations by comparative genomic hybridization (CGH). METHODS: DNA copy number changes were studied on 14 primary uveal melanomas that had not metastasized, 15 primary uveal melanomas that had metastasized, and on 6 metastases that were available from 6 primary uveal melanomas. CGH is based on quantitation of the fluorescence intensity of differentially labeled DNAs. Tumor DNA labeled with FITC dCTP and dUTP and normal DNA labeled with Texas red dCTP and dUTP were hybridized to normal metaphase chromosomes. The hybridizations were analyzed using an Olympus fluorescence microscope and the ISIS digital image analysis system to identify gain or loss of genetic material. RESULTS: Primary uveal melanomas that had metastasized and metastases had significantly more changes than primary uveal melanomas that had not metastasized. Comparison between primary nonmetastasizing tumors, metastasizing tumors, and metastases showed that the most common DNA copy number changes were -3 (21%, 73%, 67%, respectively), -6q (7%, 40%, 83%), -1p (0, 33%, 33%), -13q (14%, 13%, 50%), -8p (14%, 27%, 0), -18 (7%, 13%, 33%), +8q (14%, 53%, 100%), +6p (29%, 20%, 17%), +1q (0, 7%, 33%), and +16p (0, 7%, 33%). CONCLUSIONS: Loss of chromosome 3, loss of 6q, and gain of 8q were significantly associated with poor overall survival. In addition, losses of 1p were only found in primary uveal melanomas that had metastasized and in metastases, which suggests that this region may harbor a tumor suppressor gene important in the tumor progression. Finally, loss of chromosome 3 may be associated with isochromosome formation of 1q, 6p, 8q, 16p, 20q, and 22q.

Adult↗

[Heterochromatic regions and the nondisjunction of human chromosome 21. I. Polymorphism of the C-bands of chromosomes 1, 9 and 16 in children with Down's syndrome].

To test a hypothesis on potential role of large heterochromatic regions in chromosome nondisjunction polymorphism of C segments of chromosomes 1, 9, and 16 in 70 children with Down's syndrome were examined. The C segment lengths of the above chromosomes were shown not to deviate from the normal. To solve the problem, it seems unreasonable to examine children with Down's syndrome.

Adolescent↗

[Heterochromatic regions and chromosome 21 nondisjunction in man. II. A comparative analysis of the polymorphism of the C bands of chromosomes 1, 9 and 16 in the fathers and mothers of Down's disease children].

To test a hypothesis on potential role of large heterochromatic regions in chromosome non-disjunction, a comparative analysis of C segment lengths of chromosomes 1, 9, and 16 in fathers and mothers of children with Down's syndrome was carried out. No difference was found between the two groups. The non-disjunction in mothers is known to occur 4 times as frequently as in fathers. This fact does not allow to suppose that the heterochromatic regions may play a certain part in non-disjunction of chromosome 21.

Adult↗

DNA replication sequence in a dicentric (functionally monocentric) X chromosome formed by the joining of two X chromosomes at region p22.

In this study we used densitometry to evaluate DNA replication kinetics in a rearranged chromosome formed by the joining of two X chromosomes at region p22. No 45X mosaicism is present in peripheral blood or fibroblast cultures. The patient has primary amenorrhea, short stature, and gonadal dysgenesis. The sequence of replication in the majority of cells is p11, q11, q13, q22-24, q12, p22, q26, q28, q27, q25, and p21, q21. Thus p11 is the earliest region to replicate, and q21 is the last. In 66% of 127 cells analyzed, the replication pattern is asymmetric, and bands q12, q26, and q28 are most likely to be out of phase on the two sides of the breakpoint. We find that band p22 has a delay of replication compared to an abnormal X derived from two X chromosomes joined at the q23 region previously reported by us. Structural rearrangement may therefore delay replication in the region of the break.

Adult↗

DNA underreplication in intercalary heterochromatin regions in polytene chromosomes of Drosophila melanogaster correlates with the formation of partial chromosomal aberrations and ectopic pairing.

We studied the influence of the Suppressor of Underreplication (SuUR) gene expression on the intercalary heterochromatin (IH) regions of Drosophila melanogaster polytene chromosomes. We observed a strong positive correlation between increased SuUR expression, underreplication extent, amount of DNA truncation, and formation of ectopic contacts in IH regions. SuUR overexpression from heat shock-driven transgene results in the formation of partial chromosomal aberrations whose breakpoints map exclusively to the regions of intercalary and pericentric heterochromatin. It is important to note that all these effects are seen only if SuUR overexpression is induced during early stages of chromosome polytenization. Therefore, we developed the idea that ectopic pairing results from the joining of free DNA ends, which are formed as a consequence of underreplication.

Animals↗

Erythroblastic transformation of Philadelphia chromosome (Ph1)-positive chronic myelogenous leukemia associated with marked chromosomal rearrangements.

In a 22-year-old female with Philadelphia chromosome (Ph1)-positive chronic myelogenous leukemia (CML) a tumor consisting of megaloblastic proerythroblasts appeared in the right ilio-femoral region 2 years and 8 months after the diagnosis of the disease and was treated effectively with irradiation. She developed erythroblastic transformation 3 months after the tumor appeared. Cytogenetic study of the bone marrow cells in the acute phase revealed marked chromosomal rearrangements such as ring, dicentric, or tricentric chromosomes.

Adult↗

Yeast artificial chromosome cloning of a two-megabase-size contig within chromosomal band 18q21 establishes physical linkage between BCL2 and plasminogen activator inhibitor type-2.

The construction of large-scale physical maps requires efficient approaches to generate new probes and link informative markers. The mapping of a human chromosomal segment was initiated by using the 18q21.3 probes, plasminogen activator inhibitor type-2 (PLANH2) and BCL2, to screen a yeast artificial chromosome (YAC) library. An inverse polymerase chain reaction technique rescued genomic ends of the YAC inserts. These new probes were used in a chromosomal walking strategy which established that the PLANH2 gene was 600 kb telomeric and in the opposite transcriptional orientation to that of BCL2. Overall, 16 YACs with a mean size of approximately 300 kb were analyzed using rare-cutting restriction endonucleases and 10 end-rescued probes. A contiguous map within 18q21.3 that spans approximately 2 Mb was assembled. This establishes the feasibility of using YACs in the efficient cloning and physical surveying of expanses of the human genome lacking closely spaced, genetic landmarks.

Animals↗

Chromosome 16-specific repetitive DNA sequences that map to chromosomal regions known to undergo breakage/rearrangement in leukemia cells.

Human chromosome 16-specific low-abundance repetitive (CH16LAR) DNA sequences have been identified during the course of constructing a physical map of this chromosome. At least three CH16LAR sequences exist and they are interspersed, in small clusters, over four regions that constitute more than 5% of the chromosome. CH16LAR sequences were observed in one unusually large cosmid contig (number 55), where the ordering of clones was difficult because these sequences led to false overlaps between noncontiguous clones. Contig 55 contains 78 clones, or approximately 2% of all the clones contained within the present cosmid contig physical map. Fluorescent in situ hybridization of multiple clones, including cosmid and YAC contig 55 clones, mapped the four CH16LAR-rich regions to bands p13, p12, p11, and q22. These regions are of biological interest since the pericentric inversion and the interhomologue translocation breakpoints commonly found in acute nonlymphocytic leukemia (ANLL) subtype M4 fall within these bands. Sequence analysis of a 2.2-kb HindIII fragment from a cosmid containing a CH16LAR sequence indicated that one of the CH16LAR elements is similar to a minisatellite sequence in that the core repeat is only 40 bp in length. Additional characterization of other repetitive elements is in progress.

Animals↗

Renal oncocytoma with loss of chromosomes Y and 1 evolving to papillary carcinoma in connection with gain of chromosome 7. Coincidence or progression?

Hybrid tumors of the kidney are not rare. Previous studies of hybrid renal tumors have been valuable for the understanding of the pathogenesis and progression pathways of renal cell neoplasm. In this paper we describe the morphologic, immunohistochemical, and genetic features of 2 oncocytomas with evolving papillary renal cell carcinoma (PRCC) in a nephrectomy specimen of a 60-year old male. The patient was referred for urologic oncology consultation after the incidental discovery of a renal tumor. Nephrectomy was performed and two separate masses were present grossly. The tumors were stained with hematoxylin and eosin, cytokeratin 7 and vimentin. Genetic studies included conventional metaphase cytogenetics and fluorescence in situ hybridization (FISH). Morphologically, both tumors were oncocytomas with numerous microscopic papillary nests and psammoma bodies. Papillary carcinoma nests were highlighted with cytokeratin 7 and vimentin positivity and were more prominent in the larger tumor. Conventional cytogenetics and FISH demonstrated loss of chromosomes Y and 1 and gains of chromosome 7. We postulate that the PRCC represents a neoplastic progression by the gain of chromosome 7 oncocytoma with -Y and -1.

Adenoma, Oxyphilic↗

Molecular characterization of the pericentric inversion of chimpanzee chromosome 11 homologous to human chromosome 9.

In addition to the fusion of human chromosome 2, nine pericentric inversions are the most conspicuous karyotype differences between humans and chimpanzees. In this study we identified the breakpoint regions of the pericentric inversion of chimpanzee chromosome 11 (PTR 11) homologous to human chromosome 9 (HSA 9). The break in homology between PTR 11p and HSA 9p12 maps to pericentromeric segmental duplications, whereas the breakpoint region orthologous to 9q21.33 is located in intergenic single-copy sequences. Close to the inversion breakpoint in PTR 11q, large blocks of alpha satellites are located, which indicate the presence of the centromere. Since G-banding analysis and the comparative BAC analyses performed in this study imply that the inversion breaks occurred in the region homologous to HSA 9q21.33 and 9p12, but not within the centromere, the structure of PTR 11 cannot be explained by a single pericentric inversion. In addition to this pericentric inversion of PTR 11, further events like centromere repositioning or a second smaller inversion must be assumed to explain the structure of PTR 11 compared with HSA 9.

Animals↗

Granulocytes with segmented nucleus retain normal chromosomes 17 in Philadelphia chromosome-positive chronic myeloid leukemia with i(17q) and pseudo-Pelger anomaly. A case report studied with fluorescence in situ hybridization.

Previous reports suggested a correlation between the deletion of the terminal region of the short arm of a chromosome 17 and the appearance of dysgranulopoiesis in myeloproliferative disorders. Using the dual-color fluorescence in situ hybridization technique we analyzed the bone marrow and peripheral blood cells of a Philadelphia chromosome-positive chronic myeloid leukemia (CML) patient showing at the onset of transformation into blastic crisis both metaphases with the i(17q) as well as granulocytes without nuclear segmentation. This phenomenon is defined as pseudo-Pelger-Huët anomaly. Using two probes, one specific for 17p and one for 17q, we determined the presence or absence of the i(17q) in both metaphase and interphase cells. Moreover, we observed that all cells with a polysegmented nucleus typical of mature granulocytes did not have i(17q) but had two normal chromosomes 17. This observation confirmed the correlation between 17p deletion and the appearance of pseudo-Pelger anomaly. This finding may also be useful from a clinical point of view: the appearance of pseudo-Pelger cells in CML indicates that 17p deletion actually occurred. This event implies a negative prognosis.

Blast Crisis↗

Mapping chromosome band 11q23 in human acute leukemia with biotinylated probes: identification of 11q23 translocation breakpoints with a yeast artificial chromosome.

Translocations involving chromosome 11, band q23, are frequent recurring abnormalities in human acute lymphoblastic and acute myeloid leukemia. We used 19 biotin-labeled probes derived from genes and anonymous cosmids for hybridization to metaphase chromosomes from leukemia cells that contained four translocations involving band 11q23: t(4;11)(q21;q23), t(6;11)(q27;q23), t(9;11)(p22;q23), and t(11;19)(q23;p13). The location of the cosmid probes relative to the breakpoint in 11q23 was the same in all translocations. Of the cosmid clones containing known genes, CD3D was proximal and PBGD, THY1, SRPR, and ETS1 were distal to the breakpoint on 11q23. Hybridization of genomic DNA from a yeast clone containing yeast artificial chromosomes (YACs), that carry 320 kilobases (kb) of human DNA including CD3D and CD3G genes, showed that the YACs were split in all four translocations. These results indicate that the breakpoint at 11q23 in each of these translocations occurs within the 320 kb encompassed by these YACs; whether the breakpoint within the YACs is precisely the same in the different translocations is presently unknown.

Adult↗

Refined genetic mapping of the darier locus to a <1-cM region of chromosome 12q24.1, and construction of a complete, high-resolution P1 artificial chromosome/bacterial artificial chromosome contig of the critical region.

Darier disease (DD) (MIM 124200) is an autosomal dominant skin disorder characterized by loss of adhesion between epidermal cells and by abnormal keratinization. We present linkage analysis showing, in four families, key recombination events that refine the location of the DD locus on chromosome 12q23-24.1 to a region of <1 cM. We have constructed a YAC/P1 artificial chromosome (PAC)/bacterial artificial chromosome (BAC)-based physical map that encompasses this refined DD region. The map consists of 35 YAC, 69 PAC, 16 BAC, and 2 cosmid clones that were ordered by mapping 54 anonymous sequence-tagged sites. The critical region is estimated to be 2.4 Mb in size, with an average marker resolution of 37.5 kb. The refinement of the critical interval excludes the ALDH2, RPL6, PTPN11, and OAS genes, as well as seven expressed sequence tags (ESTs) previously mapped in the DD region. The three known genes (ATP2A2, PPP1CC, and SCA2) and the 10 ESTs mapped within the critical region are not obvious candidates for the DD gene. Therefore, this detailed integrated physical, genetic, and partial transcript map provides an important resource for the isolation of the DD gene and, possibly, other disease genes.

Chromosome Mapping↗

The chromosomes of four species of the nasuta complex of Drosophila. I. Chromosome maps and inversion polymorphism.

The salivary chromosomes of four species of the nasuta complex of Drosophila, D. sulfurigaster albostrigata, D, kohkoa, D. albomicans, and D. kepulauana were studied and chromosome maps of each species are presented; the maps of the latter three species are based on the map of D. sulfurigaster albostrigata. Three of the species D. sulfurigaster albostrigata, D. albomicans, and D. kohkoa were shown to be highly polymorphic for chromosomal inversions while the available evidence indicated that D. kepulauana is much less polymorphic. These facts are correlated with the geographic distribution of the species. Transitional homoselection has not been complete in the evolution of three of the species since D. sulfurigaster albostrigata, D. kohkoa, and D. albomicans have a number of naturally occurring polymorphisms in common.

Animals↗

Case reports of autism with interstitial deletion of chromosome 17 (p11.2 p11.2) and monosomy of chromosome 5 (5pter-->5p15.3).

Two cases of autism and autosomal chromosome abnormalities are reported: a 14-year-old boy with interstitial deletion of chromosome 17 and a 19-year-old man with an unbalanced translocation of chromosome 5, resulting in monosomy for part of the short arm (5pter-->5p15.3). The possible implications for research into the aetiology of autism are discussed.

Adolescent↗

Chromosome Y-specific DNA is transferred to the short arm of X chromosome in human XX males.

Y-chromosomal DNA is present in the genomes of most human XX males. In these cases, maleness is probably due to the presence of the Y-encoded testis-determining factor (TDF). By means of in situ hybridization of a probe (pDP105) detecting Y-specific DNA to metaphases from three XX males, it was demonstrated that the Y DNA is located on the tip of the short arm of an X chromosome. This finding supports the hypothesis that XX maleness is frequently the result of transfer of Y DNA, including TDF, to a paternally derived X chromosome.

Cells, Cultured↗