Chemoreduction in the management of retinoblastoma.
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Antineoplastic Combined Chemotherapy Protocols↗
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Pars plana vitrectomy for juxtapapillary capillary retinal angioma.
PURPOSE: To describe the treatment of juxtapapillary capillary angioma by pars plana vitrectomy (PPV) and tumor excision. DESIGN: Interventional case report. METHODS: A 6-year-old girl with symptomatic juxtapapillary capillary retinal angioma with associated epiretinal membrane (ERM) underwent PPV and extraction of the tumor and ERM. A clinical and molecular genetic workup for the presence of von Hippel-Lindau disease (VHL) was performed. RESULTS: A favorable functional result without tumor recurrence was achieved. Capillary retinal angioma was confirmed by histology of the surgical specimen, and familial VHL was revealed. CONCLUSIONS: PPV and extraction of the tumor is applicable in juxtapapillary capillary retinal angioma with associated ERM. A workup for the presence of VHL is pertinent in patients presenting with this tumor entity.
Child↗
Ischemic necrosis and atrophy of the optic nerve after periocular carboplatin injection for intraocular retinoblastoma.
PURPOSE: To report four cases of optic nerve neuropathy in three children treated with periocular carboplatin injections for unilateral or bilateral intraocular retinoblastoma. DESIGN: Retrospective, observational case series. METHODS SETTING: University-based Ophthalmology Practice. STUDY POPULATION: Four eyes of three children with retinoblastoma enucleated after nonsuccessful multimodality treatment including periocular carboplatin injections. OBSERVATION PROCEDURES: The enucleated eyes were routinely processed and evaluated by light microscopy. A retrospective chart review of all four cases was performed. RESULTS: Three enucleated eyes (Reese-Ellsworth groups III and VB) were obtained from two children with bilateral multifocal retinoblastoma, and one eye (Reese-Ellsworth group IIB) was harvested from a child with unilateral retinoblastoma. All affected eyes underwent three to seven periocular carboplatin injections before enucleation. Additional treatment modalities included systemic chemotherapy, transpupillary thermotherapy, transscleral cryotherapy, and external beam radiotherapy. Histopathologic evaluation of the enucleated eyes revealed focal areas of ischemic necrosis or atrophy of the optic nerve along with dystrophic calcification and mild inflammation in the surrounding fibrovascular adipose tissue. CONCLUSIONS: Periocular injections of carboplatin may be a useful treatment approach in the management of patients with advanced intraocular retinoblastoma and may minimize systemic side-effects. However, ophthalmologists and pediatric oncologists should be aware of potential marked local complications with periocular carboplatin delivery, including ischemic optic neuropathy. Modifying the injection site/location (for example, subtenon space) or adding other delivery routes adjuncts (for example, fibrin sealant) deserves further study.
Antineoplastic Agents↗
The expression of cyclooxygenase 2 in retinoblastoma: primary enucleated eyes and enucleation after conservative treatment.
PURPOSE: To provide insight into the relationship between cyclooxygenase-2 (COX-2) expression and histopathologic features of retinoblastoma specimens treated either by primary or secondary enucleation. DESIGN: Laboratory investigation. METHODS: Twenty-five retinoblastoma specimens received between 1994 and 2003 were retrieved for this study from the Ocular Pathology Registry, Federal University of São Paulo, Brazil and the Henry C. Witelson Ocular Pathology Laboratory and Registry, McGill University, Montreal, Canada. The specimens retrieved were divided into two groups: Group I, enucleation was performed as a form of primary treatment (n = 15) and Group II, enucleation after failure of conservative treatment (n = 10). Patient information and formalin-fixed, paraffin-embedded specimens were obtained. New sections of these blocks were used for hematoxylin and eosin stain and for immunoassay using a monoclonal mouse anti-COX-2 antibody. Two independent ophthalmic pathologists reviewed all of the microslides. RESULTS: Twenty-three specimens (92%) presented a high expression of COX-2 (15 in Group I; eight in Group II) and there was no statistical difference in COX-2 expression between the two groups (P = .07). However, all specimens expressed COX-2 to a different degree. The areas of tumor invasion were positive for COX-2 in 87.5% of the two groups. CONCLUSION: Most retinoblastoma specimens revealed a high COX-2 expression. Future studies will be necessary to correlate the high expression of COX-2 in retinoblastoma and a possible applicability of anti-COX-2 medications in the treatment of these tumors.
Antineoplastic Combined Chemotherapy Protocols↗
[New developments in 2005 for the management of visual deficit in the infant].
The main progress in ophthalmopediatrics is the knowledge of the importance and efficacy of visual refraction defects screening. This screening has to be the earliest possible, allowing a glass equipment preventing complications: amblyopia, strabismus. This screening allows the same time screening of organic anomalies and early treatment.
Age Factors↗
[Retinoblatoma: a review].
Retinoblastoma is the most frequent eye tumor in children, with an incidence of 1/15 000 births. Sixty per cent are unilateral: the median age at diagnosis is 2 years and most of these forms are not hereditary. Retinoblastoma is bilateral in 40%: the median age at diagnosis is 1 year. All bilateral and multifocal unilateral forms are hereditary. Hereditary retinoblastoma constitutes a cancer predisposition syndrome: a subject carrying a constitutional RB1 gene mutation has a greater than 90% risk of developing retinoblastoma, but is also at increased risk of developing secondary cancers. The 2 most frequent revealing symptoms are leucocoria and strabismus. Diagnosis is made by fundoscopy. US, MRI, CT scans may contribute to diagnosis. Management of patients with retinoblastoma must take into account the various aspects of the disease: the visual risk, the possibly hereditary nature of the disease and the life-threatening risk. Enucleation is still often necessary in unilateral disease; adjuvant treatment is decided according to the histological risk factors. Conservative treatment of at least 1 eye is possible in most of the bilateral cases: laser alone or combined with chemotherapy, cryotherapy and brachytherapy. The indication for external beam radiotherapy should be restricted to large ocular tumors and diffuse vitreous seeding because of the risk of late effects, including secondary sarcoma. Long-term follow-up and early information to retinoblastoma patients regarding the risk of second primary tumors and transmission is actually important.
Child↗
Constitutional genomic instability, chromosome aberrations in tumor cells and retinoblastoma.
Although retinoblastoma (Rb) is initiated as a result of biallelic inactivation of the RB1 gene, additional genetic events (M3) in tumor cells are indicative of their role in the full transformation of retinal cells. We investigated the constitutional genetic instability by fragile site (FS) expression studies and checked its relationship with loci of tumor cytogenetics in a series of 36 retinoblastoma patients (34 nonfamilial and 2 familial cases). Tumor cytogenetics revealed -13/+13, del/t(13)(q14) (50%), +1/del/t(1p/q) (65%), +6/i(6p) (60%), and del(16)(q13)/(q22 approximately q23) (60%). Conventional cytogenetics in leukocytes revealed constitutional del(13q14) in five unilateral Rb (URB) and one trilateral Rb (TRB). Constitutional del(16)(q22) and t(6;12) were also identified in two cases. Constitutional FS analysis showed a significant increase in the cellular fragility, with high prevalence at 13q14, 3p14, 6p23, 16q22 approximately q23, and 13q22 loci in retinoblastoma patients (P<0.05). Patients with constitutional del(13)(q14) demonstrated higher fragility than those with normal constitution. A strong correlation between loci of constitutional FSs and loci of recurrent chromosomal abnormalities in tumors strengthen and support the proposal that FS loci present as inherent genomic instability in retinoblastoma. The chromosomal changes and resultant genetic mutations, along with RB1 mutation events, probably contribute synergistically to the development and progression of Rb malignancy. Implementation of fluorescence in situ hybridization to nonfamilial Rb on a large scale (113 cases) could detect constitutional RB1 deletion in 12.3% of cases, with equally higher incidence in URB (14.7%) and bilateral Rb (13.6%), demonstrating that the true prevalence of patients with predisposition to RB1 mutation in sporadic URB is definitely higher in our populations. Also, higher incidence of constitutional RB1 deletion mosaicism in unilateral than in bilateral Rb indicates that the constitutional genetic mosaicism in URB should be given serious consideration during genetic counseling.
Adolescent↗
Regulation of CDKN2A/B and Retinoblastoma genes in Xiphophorus melanoma.
Xiphophorus interspecies hybrids provide several well-characterized genetic models of melanoma susceptibility. The Xiphophorus CDKN2A/B gene, homologous to mammalian CDKN2A/B cyclin-dependent kinase inhibitors (p16 and p15), is a candidate tumor susceptibility gene in these models. Using real-time PCR and Western blot analysis, we analyzed expression of CDKN2A/B in spontaneous and UV-induced primary melanomas from individual backcross hybrid fish. We found that CDKN2A/B mRNA is highly expressed in melanomas (18-fold), relative to other fish tissues. Expression is also elevated, to a lesser extent (9.5-fold), in melanized skin from tumor-bearing fish. However, quantitative levels of CDKN2A/B mRNA in tumors varied considerably and positively correlated with expression of the Xmrk oncogene, suggesting possible functional interaction between Xmrk and CDKN2A/B expression. As a homolog corresponding to members of the mammalian CDKN2 family which regulate cell cycle progression at the G1 checkpoint, the CDKN2A/B p13 protein is a putative regulator of the G1 checkpoint apparatus in Xiphophorus. Since CDKN2A is often observed to be inversely regulated compared to RB in some human tumors, and is capable of transcriptionally regulating RB in human ovarian tumors, we cloned the Xiphophorus maculatus RB cDNA and analyzed RB expression by real-time PCR and Western blot analysis in the fish melanomas. These experiments were designed to ascertain whether CDKN2A/B and RB expression were inversely correlated. Our results indicate that RB mRNA was consistently expressed at only a 2-fold higher level in both tumors and melanized skin than in muscle. Qualitatively similar results were obtained for protein expression. These results collectively suggest that (i) Xmrk and CDKN2A/B may be co-regulated at the transcriptional level, and (ii) there is little, if any, alteration of RB expression in Xiphophorus melanomas.
Amino Acid Sequence↗
Molecular studies of loss of heterozygosity in Chinese sporadic retinoblastoma patients.
BACKGROUND: Retinoblastoma, an embryonic neoplasm of retinal origin, is the most common and severe intra-ocular tumor affecting infants and young children. METHODS: Loss of heterozygosity (LOH) on chromosome 13 was investigated in 16 Chinese sporadic RB patients, using 14 microsatellite markers spanning the complete chromosome 13, to determine whether those alterations different from the alteration of RB1 gene on 13q14 may play a role in the development of RB. Loss of RB1 allele is commonly encountered in sporadic RB. Microdissected RB tissues and their matched blood DNAs were analyzed for PCR-based LOH by using fluorescence-based DNA sequencing technology. RESULTS: Of 16 RB cases, 13 showed LOH on chromosome 13. The frequency of LOH on 13q14 was about 75% (12/16), consistent with other reports. Investigation of parental origin of lost RB1 alleles showed that, in all these cases, the paternal alleles were preferentially lost. Aside from the RB1 locus, other regions with the frequency of LOH above 30% in these tumors were D13S265, D13S158, D13S170, D13S218, D13S285 and D13S159. In particular, the D13S265 locus at 13q31-32 showed the highest rate of allele loss (64%, 9/14 informative cases), suggesting the presence of 1 or several genes whose loss of function may contribute to the development of RB. Comparison of the genotypic characteristics of 3 sites of frequent LOH (D13S153, D13S263 and D13S265) with the clinicopathological phenotype, respectively, showed that LOH of each locus was preferentially associated with a significantly younger age at diagnosis of RB. CONCLUSIONS: LOH analysis at some specific loci on chromosome 13 may be of a value in RB patients as diagnostic markers.
Alleles↗
Cdk2 is dispensable for cell cycle inhibition and tumor suppression mediated by p27(Kip1) and p21(Cip1).
p27(Kip1) and p21(Cip1) are thought to suppress tumor growth and prevent cell cycle progression by inhibiting Cdk2-cyclin E/A kinases. Since Cdk2 is dispensable for mitotic cell division, we analyzed the activity of these inhibitors in Cdk2-deficient cells. Ectopic expression of p27(Kip1) or p21(Cip1) efficiently inhibits cell cycle progression of Cdk2(-/-) fibroblasts. Loss of p27(Kip1) or p21(Cip1) confers similar proliferative advantages to Cdk2(+/+) and Cdk2(-/-) cells. Moreover, Cdk2 is dispensable for p21(Cip1)-induced cell cycle arrest after DNA damage. Finally, ablation of Cdk2 in p27(Kip1) null mice does not suppress their phenotypic defects, including development of pituitary tumors. These results indicate that Cdk2 is not an essential target for p27(Kip1) and p21(Cip1) in cell cycle inhibition and tumor suppression.
Animals↗
Age at diagnosis of isolated unilateral retinoblastoma does not distinguish patients with and without a constitutional RB1 gene mutation but is influenced by a parent-of-origin effect.
Patients with hereditary cancer are usually diagnosed earlier than patients with non-hereditary tumours. In children with isolated unilateral retinoblastoma, some of whom have a hereditary predisposition, this rule has been subject to debate. We have analysed the clinical manifestation of disease in 188 children with completely resolved mutational status. In 24 (13%) of these patients, testing of blood DNA showed a constitutional RB1 mutation. The distribution of age at diagnosis was not different between patients with and without a constitutional mutation. However, patients with loss of the maternally inherited RB1 allele had an earlier age at diagnosis than patients with loss of the paternally inherited RB1 allele. Our data show that early age at diagnosis does not identify patients with isolated unilateral retinoblastoma that have a higher risk of being carriers of a RB1 gene mutation. Our findings suggest that, at least in some patients, age at diagnosis is modified by a parent-of-origin effect.
Age of Onset↗
Unilateral retinoblastoma, lack of familial history and older age does not exclude germline RB1 gene mutation.
Conclusive identification of RB1 mutations in retinoblastoma is predicted to improve the clinical management of affected children and relatives. However, despite clear clinical benefits, RB1 screening remains difficult, most of the alterations being unique and randomly distributed throughout the entire coding sequence. In this report, we present the results of a constitutional RB1 analysis undertaken in our institution over the last four years. The detection of RB1 gene deletion or mutation was performed by Southern blot and sequence analyses in 73 patients (including three families with 2, 3 and 3 probands, respectively). Complementary constitutional chromosome and fluorescent in situ hybridization (FISH) analyses of RB1 gene were applied in cases where hereditary retinoblastoma was suspected despite negative detection. Altogether, germline abnormalities were found in 11% (4/36 patients) of sporadic unilateral retinoblastoma (median age, 21.5 months) and 86% (32/37 patients) of sporadic bilateral or positive familial history retinoblastoma (median age, 5 months). The spectrum of germline alterations found in 31 distinct families included 12 nonsense mutations (39%); 10 point insertions or deletions with frameshift (32%); 4 mutations and 1 deletion affecting splice sites (16%); 2 missense mutations (6%); and 2 large deletions (6%). A total of 15 mutations have not been previously reported. In this small series, splicing mutations were associated with bilateral disease whilst most of the frameshift mutations were identified in patients with an early age at diagnosis, bilateral disease or hereditary forms of the disease. This study confirms that screening for constitutional RB1 mutation should become an integral part of current management of any patient affected by retinoblastoma irrespective of the tumour laterality and familial background.
Adult↗
Assessment of hearing in very young children receiving carboplatin for retinoblastoma.
Children with retinoblastoma have increasingly been treated with carboplatin in the past decade. Ototoxicity is a known, possible, side-effect of carboplatin. Since retinoblastoma patients are very young and frequently have impaired vision, the evaluation of hearing loss is very important. The hearing status of 25 children with retinoblastoma treated with carboplatin (median cumulative dose 2,240 mg/m(2)) was evaluated in detail. Median age at first carboplatin administration was 7 months. The evaluation of hearing loss was performed by an age-appropriate measurement protocol consisting of tympanometry, otoacoustic emission measurements, auditory brainstem responses and (high-frequency) visual reinforcement audiometry (VRA) or play-audiometry. The median follow-up time after last carboplatin dose was 25 months (range 1-94 months). In none of the children was hearing loss detected after carboplatin administration. A measurement protocol that includes tympanometry, distortion product otoacoustic emission measurements and high-frequency VRA is recommended for young children receiving carboplatin or other ototoxic drugs.
Antineoplastic Agents↗
Retinoblastoma incidence and survival in European children (1978-1997). Report from the Automated Childhood Cancer Information System project.
Based on 2283 cases of retinoblastoma diagnosed in children aged 0-14 years, incidence and survival in Europe during the period 1978-1997 are described. Data were provided to the Automated Childhood Cancer Information System (ACCIS) from 60 paediatric and general cancer registries. During 1988-1997, the cumulative incidence of retinoblastoma in the ACCIS regions was found to be between 44.2 and 67.9 per million births. The highest incidence was seen in the first year of life. The age-standardised (World standard) incidence rate for the age-range 0-14 years was 4.1 per million. Approximately one-third of cases had bilateral tumours. Overall incidence increased over the period 1978-1997 by 1% per year, as derived from a model adjusted for sex, age group and type of registry (general or paediatric). The 5-year survival rate improved from 89% to 95% during the period covered by the study. This improvement was seen in both unilateral and bilateral cases but was significant only for the unilateral tumours. Survival was lower in the East region, although smaller differences were also observed between the other four regions (British Isles, North, South and West). Availability and quality of registration data on retinoblastoma need to be improved for effective evaluation of incidence and survival.
Adolescent↗
25 Mb deletion of 13q13.3-->q21.31 in a patient without retinoblastoma.
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Adolescent↗
Biotin uptake and cellular translocation in human derived retinoblastoma cell line (Y-79): a role of hSMVT system.
The objective of this research was to investigate the presence of a specialized carrier-mediated system for biotin and delineate uptake mechanism and intracellular trafficking of biotin in the human derived retinoblastoma cell line (Y-79). Human derived retinoblastoma cell line, Y-79, was used for uptake studies. Uptake of [3H]Biotin was determined at various concentrations, pH, temperatures, in the absence of sodium and in the presence of other vitamins and metabolic inhibitors to delineate the mechanism of uptake. Uptake was determined in the presence of various intracellular regulatory pathways (protein kinase A & C, protein tyrosine kinase and calcium-calmodulin) modulators. Reverse transcription polymerase chain reaction (RT-PCR) was performed to confirm the molecular identity of human sodium-dependent multivitamin transporter (hSMVT). Uptake of [3H]Biotin in Y-79 cells were found to be saturable at micromolar concentration range, with apparent Km of 8.53 microM and Vmax of 14.12 pmol/min/mg protein, but linear at nanomolar concentration range. Uptake was sodium, pH, temperature and energy-dependent, but chloride independent; inhibited by the structural analogue desthiobiotin, pantothenic acid and lipoic acid at milimolar concentrations and not at nanomolar concentrations. Uptake of [3H]Biotin was trans-stimulated by the intracellular biotin. Ca2+/calmodulin pathways appeared to play important roles in the regulation of riboflavin uptake in Y-79 cells via significant reduction in Vmax (66%) and Km (28%) of the uptake process. A human sodium-dependant multivitamin transporter, hSMVT, was identified by RT-PCR in Y-79. These studies demonstrated for the first time the existence of a human sodium dependant multivitamin transporter (hSMVT), a specialized carrier-mediated system for biotin uptake, in human derived retinoblastoma cells.
Biological Transport↗
Antenatal ophthalmology.
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Antineoplastic Agents↗