1/21. Establishment and characterization of a second primary osteosarcoma cell line (OSrb/N-M) from a patient cured of bilateral retinoblastoma.A cell line, designated OSrb/N-M, was established from the second primary osteosarcoma that developed in a 17-year-old Japanese female patient who had suffered from bilateral retinoblastoma at infancy. The OSrb/N-M cells grew as an adherent monolayer and retained some osteogenic biochemical phenotypes. In cytogenetic analyses, this cell line revealed many structural and numerical abnormalities, however, the bands q14 of both chromosomes 13 appeared to be normal, whereas the constitutional cells displayed normal female karyotypes. Immunoblot studies using monoclonal antibodies specific to RB protein demonstrated that the tumor cells did not express RB protein, suggesting that the OSrb/N-M cells might suffer from a loss-of-function mutation at this gene locus. Thus, this cell line is useful to study the molecular mechanism for the tumorigenesis of osteosarcoma with regard to an association with retinoblastoma.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
2/21. Boy with bilateral retinoblastoma due to an unusual ring chromosome 13 with activation of a latent centromere.We present a patient with bilateral retinoblastoma and developmental delay who has an abnormal male karyotype containing 47 chromosomes, including an acentric derivative chromosome 13. We postulate that the derivative 13 occurred after a break at 13q14, with the proximal portion of the chromosome forming a ring and the distal portion undergoing duplication. Thus, this patient is trisomic for 13q14-->qter. The derivative chromosome with duplicated distal portion (13q14-->qter) lacked the 13 centromere and was negative for chromosome 13 alpha-satellite dna by low stringency FISH. Nevertheless, this chromosome is stably transmitted in lymphocytes and fibroblasts. A single primary constriction was observed at band 13q21, consistent with activation of a latent centromere (neocentromere) at this band. The neocentromere on der(13) was positive for multiple centromeric proteins, suggesting that it acts as the functional centromere. By FISH, the Rb gene was present on the normal 13, the proximally derived ring chromosome, but not on the derivative chromosome. Although there was no evidence for disruption of the Rb gene, this chromosome rearrangement most likely results in abnormal expression of the Rb gene product. copyright Wiley-Liss. Inc.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
3/21. Interstitial deletion of 13q and a 13;x chromosome translocation results in partial trisomy 13 and bilateral retinoblastoma.BACKGROUND: Abnormalities of chromosome 13 have been associated with bilateral retinoblastoma. Deletion of a retinoblastoma gene is a common primary mechanism. Other abnormalities are more rare. To our knowledge, a balanced translocation of the long arms of the X and 13 chromosomes associated with bilateral retinoblastoma has been reported five times. We report an unbalanced X;13 translocation resulting in partial trisomy 13 and an interstitial deletion of an RB locus. methods: Case report. RESULTS: A 19-month-old child presented with seizures to the emergency department. A CT scan revealed bilateral intraocular calcification, and retinoblastoma (RB) was confirmed with an ophthalmic exam. Abnormal facies and developmental delay were noted. A partial trisomy derived from the translocation of X;13 was observed in both bone marrow and peripheral blood cells. fluorescence in-situ hybridization (FISH) studies confirmed triplication of a region on the q arm of chromosome 13 spanning the RB locus. One of the normal chromosome 13 homologues had an interstitial deletion of the RB locus since no signal was observed for the RB-1 probe despite the visible presence of the 13q14 region. Additional evidence of the interstitial deletion is supported by the typical facial features and developmental delay found. Presumably, the translocated X underwent X inactivation precluding systemic features typically observed in trisomy 13. Parental karyotypes were normal. The chromosomal abnormality was a de-novo constitutional event. CONCLUSIONS: Only two RB loci were present in this patient despite triplication of 13q. The third locus was deleted. We believe that the second locus was not expressed due to X inactivation of the RB gene on the der(X)t(Xq:13q) chromosome. The emergence of bilateral retinoblastoma points towards lack of heterozygosity at the third and last remaining RB loci in tumor cells. To our knowledge, an unbalanced translocation resulting in partial trisomy 13 with retinoblastoma has not been previously reported.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
4/21. Cytogenetic abnormalities in an ossifying fibroma from a patient with bilateral retinoblastoma.cytogenetic analysis of a cemento-ossifying fibroma from a patient with nonfamilial bilateral multicentric retinoblastoma revealed three reciprocal translocations with the karyotype 46,XY,t(1;18)(q21;q21.3),t(3;10)(p13;q22),t(6;11)(p22;p15). Routine and high-resolution cytogenetic analysis of peripheral blood leukocytes showed an apparently normal, 46,XY chromosome pattern with no deletion of chromosome 13. Molecular analysis demonstrated no gross differences in the retinoblastoma gene or the TP53 gene between constitutional and tumor dna. This is the first cytogenetic analysis of a cemento-ossifying fibroma and the first report of this tumor in a retinoblastoma patient. The data may be added to the small, but growing literature on cytogenetic aberrations in benign tumors and may lend insight into genes involved in cell proliferation and neoplastic transformation.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
5/21. retinoblastoma, pinealoma, and mild overgrowth in a boy with a deletion of RB1 and neighbor genes on chromosome 13q14.We report on a 10-year-old boy with a normal karyotype and a chromosome 13q14 deletion of the retinoblastoma gene (RB1) by fluorescence in situ hybridization (FISH). He showed subtle signs of overgrowth, including macrocephaly, hepatomegaly, and inguinal hernia. The boy also had cryptorchism and mild developmental delay. In his first months of life, variant Wiedemann-Beckwith syndrome was tentatively suspected and he was included in a careful tumor prevention program. At the age of 11 months, bifocal retinoblastoma of the left eye was diagnosed. pinealoma was suspected at the age of 19 months and was removed by neurosurgery at the age of 29 months. At 4 years and 4 months, the deletion of the RB1 gene was suspected on clinical grounds and was diagnosed by FISH and molecular studies. At that time, he was a near-normal healthy playful kindergarten child, height 107 cm (-0.3 SD), OFC 52.5 cm ( 0.8 SD), developmental age 3-3.5 years. The combination of retinoblastoma, pinealoma, and deletion of the RB1 gene diagnosed by FISH has not been reported previously. The deletion spans at least 370-420 kb in size and is predicted to include proximal and distal neighbor genes. This report may assist in establishing the clinical signs of the contiguous gene syndrome at the RB1 locus on 13q14.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
6/21. Nongonadal neoplasia in patients with turner syndrome.In a prospective study of 50 patients with retinoblastoma, a 10-year-old girl with unilateral (right eye) retinoblastoma was found to have 45,X karyotype. Because there is increasing evidence of nongonadal neoplasia occurring in patients with turner syndrome in addition to the gonadal tumor from dysgenetic gonads, we reviewed the occurrence of nongonadal neoplasia in turner syndrome cases. Of all the nongonadal neoplasia, neurogenic tumors show a preponderence among children and young adults with turner syndrome. To the best of our knowledge, this is the first reported case of turner syndrome with retinoblastoma. The available literature strongly suggests that patients with turner syndrome may be at risk of developing neurogenic tumors. Further studies are necessary to identify the role of some X-linked genes that escape X-inactivation in tumorigenesis in patients with turner syndrome.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
7/21. Increased number of chromosome aberrations in the peripheral blood culture of a retinoblastoma patient.Chromosome studies were performed on blood lymphocytes from an eight-year-old patient whose left eye had been enucleated earlier because of retinoblastoma. GTG-banded karyotypes showed both numerical and structural chromosome aberrations, and the number of the patient's lymphocytes with chromosome aberration increased. It was concluded that retinoblastoma survivors need continuous control because of the increased risk of second primary tumors.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
8/21. Lymphocyte chromosome survey in 80 patients with retinoblastoma.cytogenetic analysis of eight cases of retinoblastoma patients was carried out to determine the occurrence of chromosome aberrations and to identify consistently associated clinical abnormalities. Among the 80 cases, 55 cases were unilateral, 25 cases were bilateral, seventy patients had a positive family history of Rb in 10 families. Normal chromosomes were found in 70 patients. Ten patients showed abnormal karyotypes: two cases of 13q deletion, one case of mosaicism of 13q deletion, one case of translocation between chromosomes 13 and 15 with the interstitial deletion of 13q, one case of 47, xxy, three cases of pericentric inversion of heteromorphic region of chromosome 9, two cases of pericentric inversion of chromosome Y. The patient who had the translocation between 13 and 5 with 13q deletion was found to have the characteristic midfacial appearance associated with 13q-deletion syndrome.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
9/21. Constitutional karyotype in retinoblastoma. Case report and review of literature.High resolution karyotype was performed in 13 retinoblastoma patients. A mosaic pattern for del(13)(q14.1;q14.3) was found in a girl with sporadic bilateral retinoblastoma and midface dysmorphism. In addition, 162 cases of 13q aberrations were reviewed, including 140 retinoblastoma patients and 22 non-penetrance 13q14 deletions. Some epidemiological and genetic involvements are discussed.- - - - - - - - - - ranking = 5keywords = karyotype (Clic here for more details about this article) |
10/21. Cytogenetic evidence for involvement of erythroid progenitors in a child with therapy linked myelodysplasia.A 6-year-old male with prior metastatic retinoblastoma developed a therapy linked myelodysplastic syndrome. Whole bone marrow cytogenetics showed monosomy 7 and a marker chromosome. To determine the progenitor level of origin of the malignant clone, we studied the karyotypes of marrow erythroid and granulocyte/macrophage colonies grown in methyl cellulose. All erythroid and granulocyte/macrophage colonies had an abnormal karyotype with 45 chromosomes (monosomy 7) and several colonies contained the marker chromosome. These findings give direct evidence that this patient's myelodysplastic syndrome involved an early stem cell which was capable of both erythroid and granulocyte differentiation.- - - - - - - - - - ranking = 2keywords = karyotype (Clic here for more details about this article) |
| | Next -> |