Clinical, epidemiological, and care profile of hospitalized patients with retinoblastoma in Brazil.

PURPOSE: To describe the epidemiological and clinical profile of hospitalized patients with retinoblastoma in Brazil. METHODS: Using data from the Hospital Cancer Registry of the Instituto Nacional de Câncer, patients with the morphological codes of retinoblastoma who were diagnosed between 2000 to 2018, aged 0-19 years, and followed up in registered hospitals (analytical cases) were selected. The relative and absolute frequencies of demographic, clinical, diagnostic, therapeutic, and outcome variables were described. Hospital performance indicators were calculated and compared between hospitals qualified and not qualified to treat pediatric oncology cases and between hospitals with different case volumes (<20, 20-75, >75 cases). RESULTS: Of the 2,269 identified analytical cases from 86 institutions, 48% were from the Southeast, 54% were male, and 66% were aged <4 years. The proportion of missing data (NA) was too high for several variables. Approximately 84% of the patients were from the public health system, 40% had a positive family history, and 88% had unilateral involvement. The first treatment included surgery in 58.3% of the patients (NA=2), Approximately 36.6% of these patients achieved complete remission, 10.8% achieved partial remission, and 12.7% died (NA=59%). Hospital performance indicators were within the target in >90% of the patients. The median time between the first appointment and diagnosis (6 days, interquartile range [IQR] 1-14) was significantly lower and the median time to death was longer (343 days, IQR, 212-539) in high-volume hospitals (>75 cases) than in medium- and low-volume hospitals. CONCLUSIONS: Despite the high proportion of missing data, we found that the delay in diagnosis is due to prehospital factors. Additionally, there is a need for educational programs for healthcare professionals and families that emphasize early identification and referral to specialized centers. Future studies should focus on the impact of Hospital Cancer Registry data completeness on outcomes, causes of delay in diagnosis, regional inequalities, and barriers to accessing specialized services.

Polydopamine-Based Targeted Nanosystem for Chemo/Photothermal Therapy of Retinoblastoma in a Mouse Orthotopic Model.

Background: At present, the few photothermal/chemotherapy studies about retinoblastoma that have been reported are mainly restricted to ectopic models involving subcutaneous implantation. However, eyeball is unique physiological structure, the blood-retina barrier (BRB) hinders the absorption of drug molecules through the systemic route. Moreover, the abundant blood circulation in the fundus accelerates drug metabolism. To uphold the required drug concentration, patients must undergo frequent chemotherapy sessions. Purpose: To address these challenges above, we need to develop a secure and effective drug delivery system (FA-PEG-PDA-DOX) for the fundus. Methods: We offered superior therapeutic efficacy with minimal or no side effects and successfully established orthotopic mouse models. We evaluated cellular uptake performance and targeting efficiency of FA-PEG-PDA-DOX nanosystem and assessed its synergistic antitumor effects in vitro and vivo. Biodistribution assessments were performed to determine the retention time and targeting efficiency of the NPs in vivo. Additionally, safety assessments were conducted. Results: Cell endocytosis rates of the FA-PEG-PDA-DOX+Laser group became 5.23 times that of the DOX group and 2.28 times that of FA-PEG-PDA-DOX group without irradiation. The fluorescence signal of FA-PEG-PDA-DOX persisted for more than 120 hours at the tumor site. The number of tumor cells (17.2%) in the proliferative cycle decreased by 61.6% in the photothermal-chemotherapy group, in contrast to that of the saline control group (78.8%). FA-PEG-PDA-DOX nanoparticles(NPs) exhibited favorable biosafety and high biocompatibility. Conclusion: The dual functional targeted nanosystem, with the effects of DOX and mild-temperature elevation by irradiation, resulted in precise chemo/photothermal therapy in nude mice model.

Electroretinographic changes in the inner and outer retinal layers before and after intravenous chemotherapy for retinoblastoma.

PURPOSE: To study the inner and outer retinal functions using a full-field electroretinogram (ERG) before and after intravenous chemotherapy (IVC) in children with retinoblastoma (RB). METHODS: Of the 11 eyes, seven had RB and four were normal. All children were examined under anesthesia using a handheld ERG machine with a standard protocol - light-adapted single-flash ERG (fERG), photopic single-flash 3.0- and 30-Hz flickers, and photopic negative response (PhNR) amplitudes at 72 ms (P72). The amplitudes and peak times were compared before and after IVC. RESULTS: Post-chemotherapy tumor regressed in all seven eyes. Of the seven eyes, the fERG peak time (a-wave) was delayed in two eyes (29%), whereas the b-wave was delayed in six eyes (86%). The fERG amplitude height for a- and b-waves decreased in five eyes (71%) and six eyes (86%), respectively. In addition, photopic flicker 30-Hz b-wave peak time delayed in five eyes (71%), whereas the b-wave amplitude height decreased in six eyes (86%). Simultaneously, the P72 amplitude height decreased in six eyes (86%), whereas the P-ratio increased in all seven eyes (100%). In comparison, the ERG responses improved in three of the four contralateral normal eyes. Overall, the cone function improved in two eyes (29%), whereas cone bipolar cell and retinal ganglion cell (RGC) function improved in one eye (14%) each. CONCLUSION: Comparison of light-adapted ERG changes before and after IVC showed reduced amplitudes and delayed peak times for both a and b waveforms, as well as reduced PhNR amplitude attributable to bipolar and RGC injury.

A retrospective study on adjuvant chemotherapy in retinoblastoma: validation of the new recommendation against treatment for pT2a tumors based on the 8th AJCC classification.

BACKGROUND: Retinoblastoma (RB) is an intraocular malignant tumor detected in early childhood with variable global impact. Histopathological classification of the tumor in enucleated globes with RB is the key for the decision of adjuvant chemotherapy use. We aim to validate the use of adjuvant chemotherapy in cases with combined pre-laminar/intralaminar optic nerve (ON) invasion and focal choroidal invasion according to the American Joint Committee on Cancer (AJCC) 8th classification. METHODS: This is a retrospective study conducted at King Abdulaziz University Hospital (KAUH) and King Khalid Eye Specialist Hospital (KKESH) in Riyadh, Saudi Arabia of all RB cases who underwent enucleation over 22 years (2000 to 2021). The histopathological findings were reviewed to identify the enucleated globes classified as pT2a tumors, as an inclusion criterion. Basic demographic and clinical data were collected via chart review Simple descriptive and basic statistical analysis of the data was used where applicable. RESULTS: Thirty-one patients who had an enucleated globe with RB that fit into the above classification were included. Sixteen were males and 15 were females. The median age was 14 months (IQR = 14 months). Most of the patients (93.5%) had no family history of RB. The commonest presentation was leukocoria in 87.1% followed by squint in 32.3%. Fourteen patients (45.2%) were treated by enucleation alone while 17 patients (54.8%) received adjuvant chemotherapy. Out of these, 7 patients had unilateral RB and the remaining 10 patients had bilateral RB. None of our patients developed recurrence or metastatic disease irrespective of the indication for adjuvant chemotherapy use after a maximum period of follow up reaching 17.84 years and a median of 10.6 years (IQR = 5.92). CONCLUSIONS: In patients with 8th AJCC histopathological classification of pT2a, chemotherapy following enucleation might not be justified. The outcome in our untreated group of patients did not differ from the treated group with the absence of metastasis after a relatively long period of follow up with a median exceeding 10 years in both groups. Therefore, the risk and benefit of post enucleation adjuvant chemotherapy in the treatment of unilateral RB should be carefully decided and discussed with the primary caregivers taking into consideration the most recent evidence and recommendations in the literature.

Histone Deacetylases in Retinoblastoma.

Retinoblastoma, a pediatric ocular malignancy, presents significant challenges in comprehending its molecular underpinnings and targeted therapeutic approaches. The dysregulated activity of histone deacetylases (HDACs) has been associated with retinoblastoma pathogenesis, influencing critical cellular processes like cell cycle regulation or retinal ganglion cell apoptosis. Through their deacetylase activity, HDACs exert control over key tumor suppressors and oncogenes, influencing the delicate equilibrium between proliferation and cell death. Furthermore, the interplay between HDACs and the retinoblastoma protein pathway, a pivotal aspect of retinoblastoma etiology, reveals a complex network of interactions influencing the tumor microenvironment. The examination of HDAC inhibitors, encompassing both established and novel compounds, offers insights into potential approaches to restore acetylation balance and impede retinoblastoma progression. Moreover, the identification of specific HDAC isoforms exhibiting varying expression in retinoblastoma provides avenues for personalized therapeutic strategies, allowing for interventions tailored to individual patient profiles. This review focuses on the intricate interrelationship between HDACs and retinoblastoma, shedding light on epigenetic mechanisms that control tumor development and progression. The exploration of HDAC-targeted therapies underscores the potential for innovative treatment modalities in the pursuit of more efficacious and personalized management strategies for this disease.

[Liposome co-delivery of quercetin and doxorubicin in inhibiting retinoblastoma by regulating epithelial-mesenchymal transition process].

Regulating the process of epithelial-mesenchymal transition(EMT) is an essential strategy to inhibit tumor growth and metastasis. This study is based on the EMT process of retinoblastoma and constructs quercetin(QUE) and doxorubicin(DOX) co-loaded liposome(QD Lipo) to investigate the therapeutic effect and mechanisms of combined QUE and DOX treatment on retinoblastoma. Single-factor experiments were conducted to optimize the prescription process of QD Lipo. Eventually, spherical particles with a diameter of(108.87±1.93) nm, a PDI of 0.13±0.02, and a Zeta potential of(-34.83±1.92) mV were obtained. The encapsulation rates of QUE and DOX were 96.20%±4.40% and 91.17%±4.41%, respectively. Y79 human retinoblastoma cells were used as an in vitro cellular model, and confocal microscopy demonstrated that QD Lipo could enhance Y79 uptake efficiency. The CCK-8 assay confirmed that the optimal combination therapy effect of QUE and DOX occurred at a mass ratio of 1∶1 to 1∶2. Flow cytometry showed that QD Lipo enhanced the induction of apoptosis in Y79 cells. Western blot analysis revealed that QD Lipo significantly reduced the expression of EMT pathway-related proteins vimentin and α-SMA. Fluorescence assays detected a significant decrease in ROS levels in Y79 cells after treatment with QD. These results indicated that liposomal co-delivery of QUE and DOX can enhance drug delivery efficiency to retinoblastoma cells, inhibit the EMT process in retinoblastoma by downregulating ROS levels, and enhance the cytotoxicity of DOX against retinoblastoma.

Study on the role of MYCN in retinoblastoma by inhibiting p53 and activating wnt/ßcatenin/Fra-1 signaling pathway by reducing DKK3.

Retinoblastoma (RB) is a pediatric malignancy, typically diagnosed at birth or during early childhood. The pathogenesis of RB is marked by the amplification of the Basic Helix-Loop-Helix (BHLH) Transcription Factor MYCN, which serves as a transcriptional regulator capable of binding to Dickkopf 3 (DKK3). However, the precise role of DKK3 in the malignant progression of RB cells caused by MYCN remains elusive. In the present study, the expression of MYCN was either overexpressed or interfered in RB cells. Subsequently, the expression level of DKK3 was assessed through quantitative real-time polymerase chain reaction and western blot analysis. Cell proliferation was evaluated using the Cell Counting Kit-8 assay and 5-ethynyl-2'-deoxyuridine staining, while cell cycle progression and apoptosis were analyzed by flow cytometry and western blot analysis, respectively. Additionally, the expression of proteins involved in the Wnt/ß-catenin/Fra-1/p53 signaling pathway was evaluated via western blot analysis. To gain further insights, Wnt agonists and the P53 inhibitor PFT-α were introduced into exploration. The current investigation revealed a negative correlation between the expression levels of MYCN and DKK3 in RB cells. Additionally, DKK3 overexpression inhibited cell proliferation, promoted cell apoptosis, and arrested cell cycle in RB cells with high expression of MYCN. Moreover, enhanced DKK3 expression inhibited proliferation, promoted cell cycle arrest and apoptosis of RB cells by modulating the wnt/ßcatenin/Fra-1/p53 signaling pathway. Furthermore, in vivo experiments revealed that overexpression of DKK3 inhibits the growth of RB tumors. Collectively, our findings elucidate that MYCN stimulates the Wnt/ß-catenin/Fra-1 pathway by suppressing DKK3 expression, ultimately suppressing p53 activity and contributing to malignant progression of RB.

Factors influencing parental fatigue in children with retinoblastoma based on the unpleasant symptoms theory.

Parents of children with retinoblastoma, the most common primary ocular malignant tumour in childhood, bear a heavy caregiving burden and are very susceptible to fatigue. However, little is known about their current status of fatigue and factors influencing fatigue; therefore,this study, based on the theory of unpleasant symptoms, and included 317 parents of children with retinoblastoma in China, whose general demographic data were collected, and on whom the fatigue severity scale (FSS), the generalized anxiety disorder (GAD-7) and 2-item patient health questionnaire (PHQ-2) were administered, from 9 March to 1 June 2020. The parents' FSS score and fatigue incidence were 4.41 ± 1.14 and 67.19%, respectively. The fatigue level was positively correlated with anxiety, depression, education, times of hospitalisations, and treatment types (r = 0.125-0.468, P < 0.05) and negatively correlated with health status, sleep quality, economic status, and family economic situation (r = - 0.120 to - 0.322, P < 0.05). Parent's anxiety level, being an only child and female sex of child influenced parents' fatigue. Healthcare personnel need to focus their attention on this high-risk fatigue group and implement appropriate interventions to reduce their fatigue level, promote their physical and mental health, and facilitate better care for children.

A MYCN-driven de-differentiation profile identifies a subgroup of aggressive retinoblastoma.

Retinoblastoma are childhood eye tumors arising from retinal precursor cells. Two distinct retinoblastoma subtypes with different clinical behavior have been described based on gene expression and methylation profiling. Using consensus clustering of DNA methylation analysis from 61 retinoblastomas, we identify a MYCN-driven cluster of subtype 2 retinoblastomas characterized by DNA hypomethylation and high expression of genes involved in protein synthesis. Subtype 2 retinoblastomas outside the MYCN-driven cluster are characterized by high expression of genes from mesodermal development, including NKX2-5. Knockdown of MYCN expression in retinoblastoma cell models causes growth arrest and reactivates a subtype 1-specific photoreceptor signature. These molecular changes suggest that removing the driving force of MYCN oncogenic activity rescues molecular circuitry driving subtype 1 biology. The MYCN-RB gene signature generated from the cell models better identifies MYCN-driven retinoblastoma than MYCN amplification and can identify cases that may benefit from MYCN-targeted therapy. MYCN drives tumor progression in a molecularly defined retinoblastoma subgroup, and inhibiting MYCN activity could restore a more differentiated and less aggressive tumor biology.

Retinoblastoma patients treated in Sri Lanka from 2014 to 2020: epidemiology, clinical status and correlates of lag time in seeking tertiary care services.

BACKGROUND: Retinoblastoma (RB) is a tumour of children < 5 years with a incidence of 1 in 20,000. Around 20 RB cases are diagnosed yearly in Sri Lanka, a lower middle-income country with high literacy levels and healthcare free at point of delivery. Incidence, local and systemic severity and mortality related to RB are reportedly high in low- and middle- income countries in comparison to higher income countries. Aims of this study were to describe demographic, socioeconomic, and clinical characteristics of Sri Lankan RB patients attending the designated RB unit at the Lady Ridgeway Hospital (LRH), Colombo between January 2014 to December 2020, and determine correlates of lag time (LT) for first tertiary care visit after detecting the first symptom/sign. METHODS: Two descriptive cross-sectional studies (DCSS) were conducted, one on 171 RB patients with demographic and clinical data collected between 2017 and 2020. In 2021, the second DCSS took place where socioeconomic and further demographic data were collected using telephone interviews, recruiting a subgroup of 90 (53%), consenting and contactable RB patient/ parent pairs. Bivariate and multivariable analyses were applied to determine correlates of LT of > 4 weeks for first tertiary care visit. Results were expressed as odds ratios and 95% confidence intervals. RESULTS: LRH survey (N = 171): Median age at diagnosis was 15 months (range 1-94 months; IQR: 8-27); 89 (52%) were females. Groups D and E tumours were 25.7% (n = 44) and 62.6% (n = 107) respectively with 121 (71%) enucleations. The number of deaths were 2 (1.2%). Telephone survey (N = 90): Proportion with LT of > 4 weeks for first tertiary care visit was 58% (n = 52). None of the putative risk factors (ethnicity, parental educational level, socioeconomic status, distance from residence to tertiary care unit and receiving financial assistance) were associated with LT in both analyses. CONCLUSION: Despite a high proportion with groups D and E tumours and enucleations, mortality rate was low, most likely due to availability of designated tertiary care. No correlates for LT of > 4 weeks for tertiary care presentation were identified. Early RB detection needs rigorous implementation of screening strategies and increased awareness among primary care health workers and parents.

Retinoblastoma caused by an RB1 variant with unusually low penetrance in a Danish family.

Retinoblastoma is the most common eye cancer in children. It is caused by pathogenic alterations of both alleles of the tumor suppressor gene RB1. In heritable retinoblastoma, a constitutional RB1 variant predisposes the cells to tumor formation, and loss of the other allele is a prerequisite for the development of retinoblastoma. Heritable retinoblastoma is inherited in an autosomal dominant manner; however, the majority of cases are the result of a de novo pathogenic RB1 variant. Penetrance is usually high (>90%), but with marked inter-familial variability. In some families, penetrance is incomplete and family members who develop tumors tend to remain unilaterally affected. Moreover, some families with low penetrance also show a parent-of-origin effect. We describe a patient with unilateral retinoblastoma caused by a previously unreported likely pathogenic RB1 variant (c.1199T>C) that disrupts a highly conserved amino acid residue within the A-box functional domain. Segregation analysis showed that the variant had unusually low penetrance as nine non-affected family members carried the same variant. We emphasize the use of genetic analysis on tumor DNA for classifying the RB1 variant, and underline the challenges in clinical management and counseling of families carrying the specific RB1 variant.

Safety of intravitreal chemotherapy in the management of retinoblastoma: A systematic review of the literature.

Intravitreal chemotherapy is used as a salvage therapy for retinoblastoma with persistent or recurrent vitreous seeding after primary treatment. To assess the safety of this technique, we conducted a systematic review of all studies reporting ocular toxicity data. Forty-eight trials involving 2751 eyes were included. The most common complications were cataract, retinal toxicity, and vitreous hemorrhage. However, severe and permanent adverse events were limited, while the risk of extraocular dissemination, a significant concern, was practically eliminated through preventive techniques. Globe salvage rates ranged from 29 % to 100 %. In conclusion, intravitreal chemotherapy seems to improve prognosis of eyes with advanced disease, with an acceptable safety profile. Nevertheless, most relevant studies are retrospective, and no randomized trials have been performed. Recognizing the challenges regarding the conduct of randomized studies for such a rare pediatric cancer, we believe that multicenter trials through international collaborations can significantly enhance the available information.

Bmi-1 promotes the proliferation, migration and invasion, and inhibits cell apoptosis of human retinoblastoma cells via RKIP.

Retinoblastoma is one of the most common ocular malignancies in children. Bmi-1, a member of the Polycomb group family of transcriptional repressors, is expressed in a variety of tumors. The purpose of our study was to explore the role of Bmi-1 in retinoblastoma. RT-qPCR and western blot were used for calculating the mRNA and protein levels of Bmi-1 and RKIP. MTT, Wound healing and Transwell assays were performed to measure the proliferation, migration and invasion in retinoblastoma cells. Cell apoptosis was detected by flow cytometry. The volume and mass of transplanted tumors were detected in nude mice. Bmi-1 was over expressed, and RKIP was low expressed in retinoblastoma cells. Bmi-1 promoted cell proliferation, migration and invasion and suppressed cell apoptosis of Y79 and SO-RB50 cells. Downregulation of Bmi-1 and overexpression of RKIP inhibited cell proliferation, migration and invasion, and increased cell apoptosis. The functions of Bmi-1 knockdown on retinoblastoma cells were blocked by RKIP knockdown, but promoted by RKIP. Down-regulated Bmi-1 inhibited xenograft tumor growth, and RKIP exacerbated this inhibitory effect. Bmi-1 served as a potential therapeutic target for improving the efficacy of clinical treatment in retinoblastoma. All the findings revealed the functions of Bmi-1/RKIP axis in retinoblastoma tumorigenesis.

Utility of carboplatin therapeutic drug monitoring for the treatment of neonate and infant retinoblastoma patients in the United Kingdom.

BACKGROUND: Retinoblastoma is the most common intra-ocular malignancy in children and frequently presents in very young patients who commonly require intravenous carboplatin. Delivering this is challenging due to a lack of uniform dosing recommendations, rapid changes in physiological function and the risk of side-effects. METHODS: We conducted a retrospective review of neonates and infants in the UK with retinoblastoma, who have undergone carboplatin therapeutic drug monitoring (TDM). We report on the pharmacokinetic, treatment efficacy and toxicity data. RESULTS: In total, 29 patients (median age 5 weeks at treatment onset) underwent a total of 74 TDM guided cycles of chemotherapy, involving real time sampling and dose adjustment. An additional 13 patients underwent TDM sampling to modify doses between cycles. Without the adoption of TDM guided dosing, carboplatin exposures would have been ≥20% outside the target AUC in 38/78 (49%) of treatment cycles. Excellent responses and a reassuringly low incidence of toxicities were observed following dose adjustment, despite the young patient age and the implementation of dose increases in the majority of cases. CONCLUSIONS: Real time TDM is safe, effective and deliverable for neonates and infants receiving carboplatin for retinoblastoma and should be considered standard of care up to the age of 6 months.

ALYREF/THOC4 expression and cell growth modulation in retinoblastoma.

In this study, we tested the hypothesis that ALYREF/THOC4, a poor prognostic factor in different cancer types, has potential as a drug target and prognostic biomarker for retinoblastoma (RB). Immunostaining (IHC), Western blot, and RT-qPCR analyses detected overexpression of ALYREF in the RB cell lines Y79, RB143, WERI-RB1, and RB116. IHC analysis on RB tumor array showed that 11/14 of RB tumors were ALYREF+ to varying degrees, with eight tumors at maximum 3+ intensity. The IHC analysis also detected ALYREF+ cells in normal retina, mainly in the inner nuclear and ganglion cell layer, while some tumor-bearing human eyes were ALYREF+ in the optic nerve suggesting a role in optic invasion/tumor invasion. The expression of ALYREF within the tumor itself, in the optic nerve, as well as in adjacent "normal" retina, suggest that this pattern of expression may lead to ALYREF being a potentially useful prognostic indicator for RB, as it is for other tumors. siRNA knockdown of ALYREF resulted in a 40 % decrease in cell growth in both WERI-RB1 and Y79 cells (p<0.05) and this was associated with decreased expression of mRNAs for the cell proliferation markers Ki67 and PCNA (p<0.005). These results suggest a role for ALYREF in RB cell growth regulation and its potential as both a target and a biomarker for tumor growth inhibition by anti-cancer therapies.

Targeting GPC2 on Intraocular and CNS Metastatic Retinoblastomas with Local and Systemic Delivery of CAR T Cells.

PURPOSE: Retinoblastoma is the most common intraocular malignancy in children. Although new chemotherapeutic approaches have improved ocular salvage rates, novel therapies are required for patients with refractory intraocular and metastatic disease. Chimeric antigen receptor (CAR) T cells targeting glypican-2 (GPC2) are a potential new therapeutic strategy. EXPERIMENTAL DESIGN: GPC2 expression and its regulation by the E2F1 transcription factor were studied in retinoblastoma patient samples and cellular models. In vitro, we performed functional studies comparing GPC2 CAR T cells with different costimulatory domains (4-1BB and CD28). In vivo, the efficacy of local and systemic administration of GPC2 CAR T cells was evaluated in intraocular and leptomeningeal human retinoblastoma xenograft models. RESULTS: Retinoblastoma tumors, but not healthy retinal tissues, expressed cell surface GPC2, and this tumor-specific expression was driven by E2F1. GPC2-directed CARs with 4-1BB costimulation (GPC2.BBz) were superior to CARs with CD28 stimulatory domains (GPC2.28z), efficiently inducing retinoblastoma cell cytotoxicity and enhancing T-cell proliferation and polyfunctionality. In vivo, GPC2.BBz CARs had enhanced persistence, which led to significant tumor regression compared with either control CD19 or GPC2.28z CARs. In intraocular models, GPC2.BBz CAR T cells efficiently trafficked to tumor-bearing eyes after intravitreal or systemic infusions, significantly prolonging ocular survival. In central nervous system (CNS) retinoblastoma models, intraventricular or systemically administered GPC2.BBz CAR T cells were activated in retinoblastoma-involved CNS tissues, resulting in robust tumor regression with substantially extended overall mouse survival. CONCLUSIONS: GPC2-directed CAR T cells are effective against intraocular and CNS metastatic retinoblastomas.

Focused cancer pathway analysis revealed unique therapeutic targets in retinoblastoma.

Retinoblastoma (RB) is a pediatric cancer of the eye that occurs in 1/15000 live births worldwide. Albeit RB is initiated by the inactivation of RB1 gene, the disease progression relies largely on transcriptional alterations. Therefore, evaluating gene expression is vital to unveil the therapeutic targets in RB management. In this study, we employed an RT2 Profiler™ PCR array for a focused analysis of 84 cancer-specific genes in RB. An interaction network was built with gene expression data to identify the dysregulated pathways in RB. The key transcript alterations identified in 13 tumors by RT2 Profiler™ PCR array was further validated in 15 tumors by independent RT-qPCR. Out of 84 cancer-specific genes, 68 were dysregulated in RB tumors. Among the 68 genes, 23 were chosen for further analysis based on statistical significance and abundance across multiple tumors. Pathway analysis of altered genes showed the frequent perturbations of cell cycle, angiogenesis and apoptotic pathways in RB. Notably, upregulation of MCM2, MKI67, PGF, WEE1, CDC20 and downregulation of COX5A were found in all the tumors. Western blot confirmed the dysregulation of identified targets at protein levels as well. These alterations were more prominent in invasive RB, correlating with the disease pathogenesis. Our molecular analysis thus identified the potential therapeutic targets for improving retinoblastoma treatment. We also suggest that PCR array can be used as a tool for rapid and cost-effective gene expression analysis.