National Cancer Institute®
Last Modified: September 1, 2002
UI - 12091545
AU - Hirooka K; Bertolesi GE; Kelly ME; Denovan-Wright EM; Sun X; Hamid J;
TI - Zamponi GW; Juhasz AE; Haynes LW; Barnes S T-Type calcium channel alpha1G and alpha1H subunits in human retinoblastoma cells and their loss after differentiation.
SO - J Neurophysiol 2002 Jul;88(1):196-205
AD - Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4H7.
Human retinoblastoma cells are multipotent retinal precursor cells capable of differentiating into photoreceptors, neurons, and glia. The current-voltage relation of the undifferentiated cells is dominated by a transient inward current that disappears shortly after differentiation. In 20 mM Ba(2+)-containing bath solutions, the current has an activation midpoint near -25 mV and appears to be fully inactivated at -20 mV. Sr(2+) and Ca(2+) are preferred charge carriers relative to Ba(2+), and the current vanishes in the absence of these divalent cations. Cd(2+) blocks the current with an IC(50) of 160 microM, and Ni(2+) blocks in a biphasic manner with IC(50)s of 22 and 352 microM. The current is unaffected when sodium is replaced with other monovalent cations, and it is insensitive to nifedipine, omega-conotoxin GVIA, omega-agatoxin IVA, and omega-conotoxin MVIIC. RT-PCR revealed the presence of alpha 1G and alpha 1H mRNA in undifferentiated cells, but following differentiation, a striking reduction of both alpha 1G and alpha 1H mRNA was found, and this was paralleled by the loss of T-type Ca channel currents. alpha 1I subunit mRNA levels were low in undifferentiated and differentiated cells. These results suggest that T-type Ca channels could play a role in undifferentiated retinoblastoma cell physiology since alpha 1G and alpha 1H Ca channel subunit expression is reduced in cells that have differentiated and exited the cell cycle.
UI - 12100953
AU - Parekh DJ; Jung C; O'Conner J; Dutta S; Smith ER Jr
TI - Leiomyosarcoma in urinary bladder after cyclophosphamide therapy for retinoblastoma and review of bladder sarcomas.
SO - Urology 2002 Jul;60(1):164
AD - Department of Urologic Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2765, USA.
We report an unusual case of a leiomyosarcoma of the urinary bladder after chemotherapy for retinoblastoma and the results of a review of the published reports of bladder sarcomas. A 22-year-old man presented with hematuria and was found to have a mass in his urinary bladder on computed tomography. Transurethral resection of the mass revealed a leiomyosarcoma. The patient underwent radical cystectomy and an ileal conduit was created. The final pathologic examination confirmed high-grade leiomyosarcoma. Prospective randomized combination trials similar to the Intergroup Rhabdomyosarcoma Study in the pediatric population are necessary to better understand and manage these potentially curable sarcomas.
UI - 12187430
AU - Ata-ur-Rasheed M; Vemuganti G; Honavar S; Ahmed N; Hasnain S; Kannabiran
TI - C Mutational analysis of the RB1 gene in Indian patients with retinoblastoma.
SO - Ophthalmic Genet 2002 Jun;23(2):121-8
AD - L.V. Prasad Eye Institute, L.V. Prasad Marg, Banjara Hills, Hyderabad, Andhra Pradesh, India.
Twenty-one probands, twelve with bilateral and nine with unilateral retinoblastoma, were screened for mutations in the RB1 gene using genomic DNA from peripheral blood leukocytes as well as tumors. Amplification of individual exons and flanking regions of the RB1 gene were carried out, followed by direct sequencing of the amplified products. Sequences of affected individuals were compared with those of controls. Mutations were identified in seven patients, five with bilateral and two with unilateral retinoblastoma. Six out of seven mutations involved the formation of premature termination codons by means of single base substitutions (2), frameshifts due to splice-site mutations (2), or deletion and duplication (2). One missense mutation was identified. Of the remaining fourteen patients, seven with bilateral disease had no mutations in peripheral blood (7 cases) or tumors (3/7 cases). Analysis of the peripheral blood of seven patients with unilateral disease also showed no mutations. Mutations were detected in about one-third of the cases, suggesting that hemizygous deletions at the RB1 locus or mutations outside the coding regions of RB1 may be responsible for the disease in the remaining patients.
UI - 12187432
AU - Moll AC; Imhof SM; Bouter L; den Otter W; Koten JW
TI - An infant with Down syndrome and retinoblastoma. A possible non-fortuitous association.
SO - Ophthalmic Genet 2002 Jun;23(2):135-6
UI - 12187428
AU - Lubinski W; Zajaczek S; Sych Z; Penkala K; Palacz O; Lubinski J
TI - Electroretinographic changes in the inner retinal layers of the retained eyes of patients with sporadic unilateral retinoblastoma.
SO - Ophthalmic Genet 2002 Jun;23(2):99-107
AD - Clinic of Ophthalmology, Pomeranian Academy of Medicine, Szczecin, Poland. firstname.lastname@example.org
PURPOSE: Examination of retinal function as measured by flash electroretinogram (ERG) including oscillatory potentials (OPs) and pattern electroretinogram (PERG) in a series of patients with unilateral sporadic retinoblastoma. PATIENTS: Studies were undertaken in the retained eye (without clinical evidence of retinoblastoma) of 13 patients with sporadic unilateral retinoblastoma and in 13 healthy controls. METHODS: Standard flash ERG including scotopic OPs and PERG recordings were performed in accordance with the International Society for Clinical Electrophysiology of Vision (ISCEV) standards. RESULTS: Statistically significant differences between the studied and the control groups were observed with flash ERG (OP1 amplitude increase, p < 0.003; photopic flicker amplitude increase, p < 0.05) and PERG (P50 latency increase, p < 0.008). CONCLUSIONS: Inner retinal layer dysfunction may be a characteristic feature of individuals with unilateral sporadic retinoblastoma.
UI - 12210086
AU - Schneider-Stock R; Boltze C; Jaeger V; Stumm M; Seiler C; Rys J; Schutze
TI - K; Roessner A Significance of loss of heterozygosity of the RB1 gene during tumour progression in well-differentiated liposarcomas.
SO - J Pathol 2002 Aug;197(5):654-60
AD - Department of Pathology, Otto-von-Guericke University, 39120 Magdeburg, Leipziger Strasse 44, Germany. email@example.com
Tumour progression can be investigated in liposarcomas showing a transition from a low-grade well-differentiated (WD) to a high-grade dedifferentiated (DD) variant. As RB1 gene alterations are common defects in sarcomas, this study examined the frequency of RB1 loss of heterozygosity (LOH) in a group of 14 well-differentiated liposarcomas (WDLs) and 17 well-differentiated/dedifferentiated liposarcomas (WD/DDLs), using a microdissection approach (PALM laser pressure catapulting) that allows the two histological components to be separated for polymerase chain reaction (PCR) analysis. In addition, RB1 protein expression and the Mib1 proliferation index were determined by immunohistochemistry and interphase FISH was performed with an RB1 probe at 13q14. By the use of four intragenic polymorphic RB1 markers (introns 1, 17, 20, and 25) for PCR, allelic losses were found only in the DD parts, but never in the pure WDLs or in the WD components of the WD/DDLs investigated. Furthermore, DD areas characterized by a heterogeneous RB1 protein expression pattern (35-65% immunopositivity), as compared with 90-100% RB1 positivity in WD areas, showed a marked increase in Mib1 proliferation index (19.6% versus 1.8% in WD areas; p<0.001). Interphase fluorescence in situ hybridization (FISH) detected a higher RB1-LOH rate in the DD components of WD/DDLs. Considering the different detection sensitivities of the three methodologies, it is concluded that loss of RB1 function already begins in the WDL, and that the tumour cell population with RB1-LOH starts prevailing in the tumour mass during progression of a WDL. Copyright 2002 John Wiley & Sons, Ltd.
UI - 12215103
AU - McCaffery S; Wieland MR; O'Brien JM; Cooper KL; Wieland MR; Wendel RT
TI - Atypical retinoblastoma presentations: a challenge for the treating ophthalmologist.
SO - Arch Ophthalmol 2002 Sep;120(9):1222-5
AD - Ocular Oncology Division, Department of Ophthalmology, University of California San Francisco, 10 Koret Way, Room K-301, Box 0730, San Francisco, CA 94143-0730, USA.
UI - 12215105
AU - Abramson DH; Schefler AC; Beaverson KL; Rollins IS; Ruddat MS; Kelly CJ
TI - Rapid growth of retinoblastoma in a premature twin.
SO - Arch Ophthalmol 2002 Sep;120(9):1232-3
AD - DHAMD@aol.com
UI - 11913235
AU - Bouguila H; Malek I; Boujemaa C; Mouelhi M; Daghfous F; Nacef L; Ayed S
TI - [Prognosis of retinoblastoma. Report of 50 cases]
SO - J Fr Ophtalmol 2001 Dec;24(10):1053-6
AD - Service du Pr S. Ayed, Institut Hedi Raies d'Ophtalmologie de Tunis, Bab Saadoun, Tunis.
PURPOSE: The aim of this study was to analyze the factors influencing the prognosis of retinoblastoma. MATERIALS AND METHODS: In 50 children with retinoblastoma, 69 eyes were reviewed. All patients had a full ophthalmic examination, a B-scan ultrasound, a computerized tomography scan and a pediatric examination. We performed enucleation in 47 eyes (with a histopathological study), external beam irradiation in 16 eyes, curitherapy in 4 eyes, cryotherapy in 3 eyes, and adjuvant chemotherapy in 7 cases. RESULTS: The global survival rate was 87.5%. The main aggravating factors were: the size of the tumor and the extraretinal involvement with extension within the chroid, the sclera, and the optic nerve. CONCLUSION: The prognosis of retinoblastoma mainly depends on the extraretinal invasion.
UI - 12144826
AU - Choi HH; Jong HS; Hyun Song S; You Kim T; Kyeong Kim N; Bang YJ
TI - p130 mediates TGF-beta-induced cell-cycle arrest in Rb mutant HT-3 cells.
SO - Gynecol Oncol 2002 Aug;86(2):184-9
AD - Cancer Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea.
OBJECTIVE: The retinoblastoma proteins include Rb and the functionally and structurally related proteins p107 and p130. It has been reported that HT-3 cells are sensitive to TGF-beta growth inhibition, despite the Rb mutation. The purpose of this study was to elucidate the growth-inhibitory mechanism of TGF-beta in Rb mutant HT-3 cells. METHODS: Growth inhibition by TGF-beta in cervical carcinoma cell lines was evaluated by counting cell numbers. Cell-cycle distribution was determined by staining DNA with propidium iodide (PI) and measured using a flow cytometer. The level of each protein expression was determined by Western blot analysis. To evaluate the assembly of cdk2/p21, cdk2/cyclin E, and E2F-4/p130 complexes by TGF-beta, immunoprecipitation was performed. RESULTS: TGF-beta inhibited the proliferation of HT-3 cells expressing mutant Rb protein and efficiently induced cell-cycle arrest at G(1) phase. p21 protein level was elevated in TGF-beta-treated HT-3 cells, while other G(1) regulatory protein levels were unaltered. TGF-beta markedly enhanced the binding of p21 with cdk2 but decreased that of cdk2 with cyclin E and inhibited the phosphorylation of p130 but did not change Rb and p107 protein status. We also found that E2F-1 protein level was lower in TGF-beta-treated cells and suggest that this might be the result of enhanced binding between E2F-4 and p130. CONCLUSIONS: Our results demonstrate that p130, instead of Rb, can mediate growth inhibition by TGF-beta in Rb mutant HT-3 cells.
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