Editorial: chemotherapy for retinoblastoma.
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Combined chemotherapy and local treatment in the management of intraocular retinoblastoma.
BACKGROUND: To assess the efficacy of chemotherapy (chemoreduction) plus local treatments as an alternative to external beam and enucleation for intraocular retinoblastoma. MATERIALS AND METHODS: A prospective study was performed on 21 patients with retinoblastoma treated in our institution from September 1997 to December 2000 to study the ocular outcome of those 33 eyes. RESULTS: There were 9 unilateral and 12 bilateral retinoblastoma cases. There were 12 eyes with Reese-Ellsworth group I-IV and 21 eyes with group V. Among 33 eyes, nine eyes (27%) were initially managed by enucleation. The remaining 24 eyes (73%) were initially treated with chemoreduction (maximum of six cycles of carboplatin, vincristine, etoposide) or chemothermotherapy. Among those 24 eyes, 20 were successfully treated with local treatments (thermotherapy plus cryotherapy in 16 eyes and thermotherapy plus cryotherapy plus (125)I plaque radiotherapy in 4 eyes), enucleation eventually underwent in two eyes and was proposed but refused in one child with bilateral group V retinoblastoma. With a median follow-up of 21 months, conservative management without external beam radiation was successful in all 12 eyes with group I-IV and in a total of 20/33 eyes (60%). Among the nine cases of unilateral retinoblastoma, eight were enucleated but among the 24 eyes with bilateral retinoblastoma, 19 (79%) were successfully treated with conservative therapy. CONCLUSIONS: It may be possible to eradicate viable tumor in all eyes with Reese-Ellsworth group I-IV retinoblastoma by chemoreduction followed by local treatments. Although 8 out of 21 eyes (38%) with group V retinoblastoma may be salvaged after chemoreduction and local therapies, enucleation remained the treatment of choice in those eyes with total retinal detachment and diffuse vitreous seeding.
Antineoplastic Combined Chemotherapy Protocols↗
Episcleral plaque brachytherapy for retinoblastoma.
BACKGROUND: The purpose of this study was to report our experience using episcleral plaque brachytherapy (EPBRT) to treat retinoblastoma and to demonstrate its applicability in multimodality treatment. PROCEDURE: We treated 26 tumors in 25 eyes from a group of 21 children with unilateral (n = 4) or bilateral (n = 17) retinoblastoma. The group comprised 8 girls and 13 boys; the median age was 25 months (range: 2-64 months) at the time of EPBRT. Iodine-125 ((125)I) was used for all applications. The median dose was 44 Gy (range: 35-47.6 Gy). EPBRT was administered primarily at the time of relapse after primary chemotherapy or radiation therapy. RESULTS: For eyes treated with EPBRT, the eye preservation rate was 15/25 with a median follow-up of 47 months (range: 2-198 months); the lesion control rate was 25/26 with a median follow-up of 13 months (range: 1-140 months). The median time to additional whole-eye treatment after EPBRT was 12 months (range: 2-105 months). CONCLUSIONS: Similar to previously reported series, EPBRT shows a high rate of successful tumor control as a primary treatment for retinoblastoma, as well as a secondary therapy at the time of relapse. EPBRT also allows for a clinically significant delay in the time to additional measures for the affected eye. Therefore, EPBRT should be considered as a form of local ophthalmic therapy that avoids or delays the use of external-beam radiotherapy, especially for patients primarily treated with chemotherapy who might require consolidation therapy.
Brachytherapy↗
Outcome of retinoblastoma in east Africa.
We estimated the proportion of patients reaching a pediatric ophthalmology unit (Comprehensive Community Based Rehabilitation for Tanzania Disability Hospital, CCBRT) or an oncology unit (ORCI) in east Africa and investigated presentation, histology, and treatment outcomes of patients with retinoblastoma. A 5-year retrospective study identified 91 patients, representing approximately 18% of the nationwide total. Mean lag time was 10 months (standard deviation (SD) = 17) and mean follow-up was 8 months (SD = 11, range 0-40, n = 91). Thirty months disease-free survival probability was 0.23 (standard error = 0.07). Outcomes for retinoblastoma in Africa remain poor. The data presented here suggest strategies for improving the outcomes, including encouraging earlier presentation and establishment of multi-disciplinary treatment centers.
Child, Preschool↗
High-precision isotope ratio mass spectrometry and stable isotope precursors for tracer studies in cell culture.
The use of stable isotope-labeled tracers is demonstrated in an in vitro system with analysis by high-precision isotope ratio mass spectrometry (IRMS), using n-3 long-chain polyunsaturated fatty acid (LCP) biosynthesis from [U-(13)C]18:3n-3 (18:3n-3*) in Y79 human retinoblastoma cells as a model system. The cells were cultured as a suspension in RPMI 1640 medium supplemented with 15% fetal calf serum at 37 degrees C with 5% CO(2) in air. They were harvested by sedimentation and cell lipids were extracted to determine the presence of 18:3n-3* metabolites using gas chromatography-combustion (GCC)-IRMS. As the dose of 18:3n-3* was systematically increased from treatment to treatment, the atom percent excess and the amounts of biosynthesized LCP* increased, while the percentage dose in each n-3 LCP* remained constant. Cultures incubated with 0.5 micromol (10 microM) of albumin-bound 18:3n-3, composed of 18:3n-3* diluted 1/60 or 1/100 with natural abundance 18:3n-3, yielded products with enrichments about 1.5 at.% excess (delta(13)C(PDB) < 1500 per thousand), which is optimal for high-precision measurements. Kinetics in Y79 cells incubated with 18:3n-3* showed that n-3 LCP* incorporation increased over time; 18:3n-3*, 20:5n-3*, 22:5n-3*, and 22:6n-3* were detected at all time points with the 1/60 dilution. These data document experimental parameters for optimal stable isotope use and IRMS detection for in vitro tracer methodology.
Carbon Isotopes↗
Design and implementation of a relational database used in the management of patients with retinoblastoma.
Clinical data are most useful in the management of patients with complex medical problems if they are accurate, reliable, and easily accessible by physicians and the medical community at large. Furthermore, the data are most valuable when they can be shared among cooperating institutions. We describe a computer system which exhibits a uniform taxonomy, an integrated on-line dictionary of clinical terms, a coherent temporal layout, and persistent spatial integrity with regard to the values of the variables. The system is user friendly and provides real time data access which can be retrieved by structured query language or may be programmed to be used as part of an international network in the management of patients with retinoblastoma, a malignant and potentially fatal tumor of childhood. Furthermore, because of its design flexibility, this system provides for potential application to other ophthalmic disorders, such as malignant uveal melanoma, and other areas of medicine as well.
Databases, Factual↗
Involvement of p53 and WAF1/CIP1 in gamma-irradiation-induced apoptosis of retinoblastoma cells.
Retinoblastoma is an intraocular malignancy of childhood, which is very radiosensitive. gamma-irradiation, however, induces side effects, and the precise mechanisms of tumor cell death after the treatment remain unknown. In this study, we demonstrated that gamma-irradiation induced apoptosis (programmed cell death) in human retinoblastoma cell lines Y79 and WERI-Rb-1. The expression levels of p53, tumor suppressor gene product, and its-associated protein, WAF1/CIP1, were both up-regulated, and function of p53 was remarkably activated after the treatment. Moreover, apoptosis was induced in the absence of gamma-irradiation by overexpression of the WAF1/CIP1 gene in both retinoblastoma cells. These results indicate that the transfer of the WAF1/CIP1 gene may have potential for the treatment of human retinoblastomas instead of gamma-irradiation.
Apoptosis↗
Expression of tyrosinase-related protein 2/DOPAchrome tautomerase in the retinoblastoma.
Tyrosinase-related protein 2 (TRP-2), also known as DOPAchrome tautomerase, is an enzyme in melanin biosynthesis and may play an important role in detoxification of a metabolite derived from DOPA. TRP-2 is expressed in melanocytes of neural crest origin and retinal pigment epithelium (RPE), derived from the optic cup. TRP-2 has been established as an early differentiation marker for melanoblasts and RPE. It is therefore of significance to study the regulation of TRP-2/DOPAchrome tautomerase expression. Here we show that TRP-2 mRNA is expressed in Y79 human retinoblastoma cell line, derived from a primitive multipotential retinal cell. Retinoblastoma is the common primary intraocular tumor of childhood. Basal expression levels in Y79 retinoblastoma cells of TRP-2 mRNA and protein are comparable to those in melanoma cells, whereas mRNA for tyrosinase, the rate-limiting enzyme in melanogenesis, is undetectable in retinoblastoma cells. Transient transfection assays showed that the TRP-2 gene promoter efficiently directs the reporter gene expression in retinoblastoma cells as it does in melanoma cells. Moreover, the expression of TRP-2 mRNA was induced by retinoic acid in retinoblastoma cells but not noticeably affected by forskolin, a cAMP-elevating reagent, whereas in melanoma cells its expression was induced by forskolin but not by retinoic acid. These results suggest a difference in the regulation of TRP-2 expression between retinoblastoma and melanoma cells. Moreover, TRP-2 mRNA is expressed in the excised retinoblastoma specimens, as assessed by RT-PCR. The present study shows unexpected features of TRP-2 and may enhance our understanding of the pathophysiology of retinoblastoma.
Colforsin↗
Glutamate and antimitotic agents induce differentiation, p53 activation, and apoptosis in rodent neostriatal cell lines immortalized with the tsA58 allele of SV40 large T antigen.
The tsA58 allele of SV40 large T antigen has the ability to immortalize cells, which is thought to be due, in part, to binding of p53 protein by T antigen at 33 degrees C. At the nonpermissive temperature (39.5 degrees C), it is thought that p53 is released, inducing growth arrest, vulnerability to apoptosis, and loss of the immortal phenotype. In cell lines derived from the rat neostriatum immortalized with tsA58, the toxic agents Adriamycin, cytosine arabinoside, and glutamate induced apoptosis and increased p53 activity and differentiation. The apoptosis and p53-inducing effects of the drugs were not greater at 39.5 degrees C compared to 33 degrees C, suggesting that p53 is not effectively blocked even at 33 degrees C. Growth arrest was not induced under most treatment conditions despite p53 induction. On the other hand, process extension was enhanced at 39.5 degrees C compared to 33 degrees C. Therefore, these cell lines are temperature sensitive with respect to differentiation, but not growth regulation or apoptosis.
Alleles↗
Retinoblastoma: the disease, gene and protein provide critical leads to understand cancer.
Retinoblastoma has contributed much to the understanding of cancer. The protein product of the RB gene, pRB, is a multifaceted regulator of transcription which controls the cell cycle, differentiation and apoptosis in normal development of specific tissues. Elucidating the mechanisms in which pRB plays a critical role will enable novel therapies and strategies for prevention, not only for retinoblastoma, but for cancer in general.
Genes, Retinoblastoma↗
Intercellular junctions: downstream and upstream of Ras?
Most human tumors are of epithelial origin, and these tumors gradually lose their epithelial character in a process termed the epithelial-mesenchymal transition. Approximately 40% of human tumors have activating mutations in one of the three RAS genes. Given these statistics, it is critically important to understand the role of Ras signaling in the epithelial-mesenchymal transition. This review considers the mechanisms and effectors through which Ras may regulate intercellular junction formation in epithelial cells. Conversely, intercellular junction proteins themselves may play a role in regulating Ras activation and signaling.
Animals↗
Melatonin enhances retinoic acid induction of cone arrestin gene expression in retinoblastoma cells.
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Arrestin↗
Verification of ophthalmic brachytherapy treatment planning.
Ophthalmic brachytherapy dose calculations were performed as an independent verification of commercial dosimetry software (BEBIG Plaque Simulator). Excel spreadsheets were constructed to follow the formalism of the AAPM Task Group No. 43. As a software commissioning tool, TG43 seed-based coordinates were reformatted to be compatible with plaque-based BEBIG dose tables for centrally positioned seeds. Plaque central axis doses were also calculated for rings of seeds. Close agreement with BEBIG doses was obtained in both cases. Tailored spreadsheet versions were subsequently created to verify patient treatment plans. Treatment time and dose to a specified central-axis point are calculated for ROPES plaques fully loaded with 1-125 model 6702 seeds.
Brachytherapy↗
Retinoblastoma: genetic testing versus conventional clinical screening in India.
INTRODUCTION: Genetic testing is increasingly being used to evaluate susceptibility to hereditary diseases because it is a cost effective screening method. Predictive testing for retinoblastoma can help to save the vision and avoid unnecessary (and invasive) eye examinations for probands and their close relatives. This study was undertaken to evaluate the cost effectiveness of the retinoblastoma genetic screening strategy established in our hospital. STUDY DESIGN: Cytogenetic study of peripheral blood, mutational, and methylation analyses from the tumor DNA of 25 patients with retinoblastoma was undertaken. The cost for retinoblastoma (RB1) gene screening was calculated based on the cost of the chemicals and consumables used and the clinical examination charges at our hospital. A comparison was made between the cost of genetic screening and clinical testing for retinoblastoma. Retinoblastoma patients underwent clinical management and genetic testing at Sankara Nethralaya, Chennai, India. RESULTS: By adopting a genetic screening strategy, a 3.5-fold cost saving was seen for a proband while a 6-fold saving was seen for a family with two sibs compared to the cost of clinical examination. The clinical examination fee and cost of genetic screening for a proband was dollarUS536 and dollarUS152, respectively, while for a nuclear family with two sibs the costs were dollarUS1071 and dollarUS175, respectively. DISCUSSION: Savings for a family will be higher if indirect costs, such as savings in travel times to and from the hospital and labor savings, were taken into account. Cost will be a major factor in determining the implementation of genetic screening for RB1 gene in the clinical practice. CONCLUSION: In our study in India, genetic screening for retinoblastoma was cheaper than conventional screening and was useful in the genetic counseling of the families.
Child, Preschool↗
Retinoblastoma - MR appearance using a surface coil in comparison with histopathological results.
PURPOSE: The purpose of this work was to evaluate the characteristic appearance of untreated retinoblastoma on a large sample in comparison to the histological findings after therapeutical enucleation. MATERIALS AND METHODS: In a prospective clinical trial 46 children with retinoblastoma in 63 affected untreated eyes were examined under general anesthesia on MRI using a 1.5-T system. The examinations were performed with a special surface coil applying an examination protocol including fast T2- and T1-weighted spin echo sequences and additional fast T1-WI after intravenous injection of Gd-DTPA in different planes. The imaging results were compared to the histopathological findings in 29 patients with 30 affected eyes. RESULTS: Comparing MRI findings and histopathological results, optic nerve infiltration was detected with a sensitivity of 53.8% and a specificity of 82.3% on MRI, infiltration of the choroid with a sensitivity of 75.0% and a specificity of 100.0%, and the degree of tumor calcification with a sensitivity of 91.7% and a specificity of 88.9%. In this study the characteristic MR appearance of untreated retinoblastoma was evaluated. CONCLUSION: MRI was helpful in relevant aspects of pretherapeutical retinoblastoma staging, deficits remain regarding optic nerve infiltration.
Child↗
[Unilateral nocturnal glare sensitivity and photopsias].
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Female↗
[Juxtapapillary capillary retinal angioma with epiretinal membrane of the macula in familial Von-Hippel-Lindau-Syndrome].
A case of juxtapapillary capillary retinal angioma associated with a vascularized epiretinal membrane of the macula in a 6-year-old girl is presented. Von-Hippel-Lindau-Syndrome was revealed by molecular genetic methods, and further family members were identified as gene carriers. The retinal angioma embedded in an epiretinal membrane was removed completely with the membrane by pars plana vitrectomy with a good functional result. Histopathology confirmed the diagnosis of capillary angioma.
Child↗