Development Of Retinoblastoma Research Articles

Subset of retinoblastoma tumours is associated with BRCA1/2 mutations

BackgroundWe investigated the potential association between pathogenic BRCA1/2 variants and retinoblastoma pathogenicity.MethodsIn this single-centre, retrospective case series, we performed hereditary cancer panel tests using blood samples for patients with retinoblastoma...

MiR-889-3p targeting BMPR2 promotes the development of retinoblastoma via JNK/MAPK/ERK signaling

MicroRNAs (miRNAs) are vital regulators of tumor pathogenesis, including that of retinoblastoma (Rb). This study investigated the functions and mechanisms of action of miR-889-3p in Rb. BMPR2 and miR-889-3p levels were assessed by quantitative reverse transcription PCR (qRT-PCR) or western blotting. Through several cell function tests, the effects of miR-889-3p and BMPR2 on cell proliferation, migration, and JNK/MAPK/ERK signaling were evaluated. The interaction between miR-889-3p and BMPR2 was investigated using a luciferase reporter assay. In vivo tumor development was investigated using a xenograft test. The association between miR-889-3p and BMPR2 expression was identified using Pearson’s correlation analysis. miR-889-3p was increased in Rb cells, and miR-889-3p knockdown inhibited Rb cell proliferation, migration, and phosphorylation of c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and ERK1/2 in vitro, as well as tumor growth in vivo. Further, they were inversely associated in Rb tissues and miR-889-3p may directly attached to the 3′-UTR of BMPR2 mRNA. Finally, the inhibition of BMPR2 inverted the negative effects of the miR-889-3p inhibitor on migration, proliferation, and activation of JNK, p38 MAPK, and ERK1/2 in Rb cells. Our results indicate that miR-889-3p, which targets BMPR2 and promotes Rb growth by controlling the JNK/MAPK/ERK pathway, is an oncogene in Rb. These results suggested that the miR-889-3p/BMPR2 axis may be a new therapeutic target for Rb.

METTL14-Mediated m6a Modification of CDKN2A Promotes the Development of Retinoblastoma by Inhibiting the p53 Pathway.

The methyltransferase 14, N6-adenosine-methyltransferase subunit (METTL14) and Cyclin-dependent kinase inhibitor 2A (CDKN2A) have been identified as involved in the regulation of various cancer progression, while their mechanism and regulatory effect in retinoblastoma (RB) is still unclear. Cell colony formation, CCK-8 as well as Western blotting were used to evaluate the proliferation, apoptosis as well as p53 protein level of RB cell line. The METTL14 and CDKN2A levels were detected by qRT-PCR or Western blotting when METTL14 was up-regulated or CDKN2A was down-regulated. MeRIP and Pearson analysis were performed to confirm the regulatory relationship between METTL14 among CDKN2A. We found that the levels of CDKN2A and METTL14 were abundant in RB samples, as well as RB cells. METTL14 enhances N6-methyladenosine (m6A) modification of CDKN2A to upregulate its mRNA and protein levels. The proliferation of RB cells can be inhibited by silencing CDKN2A, which promotes apoptosis and p53 protein level. Furthermore, high-expression of METTL14 eliminated the anti-tumor effect of CDKN2A silencing in RB progression in vitro. CDKN2A is mediated by METTL14-m6A modified and restrains p53 pathway activation to accelerate the malignancy of RB. This points to the METTL14-m6A-CDKN2A-p53 pathway axis as a possible prospective target for the future RB treatment.

LncRNA RBAT1 reduces chemosensitivity of cancer cells to carboplatin/paclitaxel by sponging miR‑27b in endometrial carcinoma

BackgroundA recent study reported the role of long non-coding RNA (lncRNA) RBAT1 in promoting the development of retinoblastoma and bladder cancer. However, its function in other cancers is unclear. We then studied the role of RBAT1 in endometrial carcinoma (EC).MethodsThe expression of RBAT1 and miR-27b in EC and paired non-tumor samples from advanced EC patients, as well as in plasma samples of EC patients and healthy controls were detected by RT-qPCR. The direct interaction between RBAT1 and miR-27b, and the subcellular location of RBAT1 were determined by RNA-RNA pulldown assay and subcellular fractionation assay, respectively.ResultsEC tissues showed increased expression levels of RBAT1 and decreased expression levels of miR-27b compared to that in non-tumor tissues. Moreover, EC patients showed higher plasma expression levels of RBAT1 and lower plasma expression levels of miR-27b compared to that in the controls. Drug-resistant (DR) patients showed higher expression levels of RBAT1 and lower expression levels of miR-27b in both EC tissues and plasma samples. RBAT1 was detected in both nuclear and cytoplasm and it directly interacted with miR-27b. RBAT1 and miR-27b did not affect the expression of each other. Upregulation of RBAT1 promoted the expression of multidrug-resistant-related protein (P-gp, MRP1, and BCRP). Overexpression of RBAT1 and inhibition of miR-27b promoted cell viability and impeded cell apoptosis and cell cycle arrest at G0-G1 phase, while knockdown of RBAT1 and overexpression of miR-27b inhibited cell viability and induced cell apoptosis and cell cycle arrest at G0-G1 phase. Moreover, miR-27b could abolish RBAT1-induced effects on cell viability, apoptosis and cell cycle.ConclusionRBAT1 may reduce the chemosensitivity of EC cells to carboplatin/paclitaxel by sponging miR-27b in EC.

The association between maternal nutrient intake during pregnancy and the risk of sporadic unilateral retinoblastoma among offspring

Previous studies have associated maternal diet during pregnancy with the development of sporadic unilateral retinoblastoma (RB), but few studies have focused on the role of individual nutrients. The aim of this study is to investigate the association between maternal nutrient intake during pregnancy and the development of sporadic unilateral RB in the offspring.A modified food frequency questionnaire, with additional questions on supplement use, was completed via a phone interview. Cases were recruited from hospitals and controls were comprised of friends and relatives of the patient without a history of cancer. Overall, 168 sporadic unilateral RB cases and 145 controls were included in case-control study. We performed logistic regression to estimate odds ratios (ORs) and 95 % confidence intervals (CI), adjusting for child’s age, child’s sex, parental race/ethnicity, maternal education, total calorie intake during pregnancy, maternal age at birth, maternal smoking during pregnancy, pre-pregnancy body mass index, maternal weight gain during pregnancy, paternal age at birth, and maternal multivitamin use in the year before pregnancy.In the adjusted model, the interquartile (IQR) increase in vitamin A intake, which was measured in retinol activity equivalent (RAE; OR: 0.64, 95 % CI: 0.46–0.90), and vitamin D intake (OR: 0.62, 95 % CI: 0.42–0.91) significantly reduced the risk of sporadic unilateral RB.These findings suggest that a higher intake of vitamins A and D can be a protective factor for sporadic unilateral RB. Further analyses in consideration of multi-exposures such as parental occupational exposures are warranted to discover the complex etiology of sporadic unilateral RB. In addition, the role of nutritional epigenetics for how maternal nutrient intake influences the risk of sporadic unilateral RB in the offspring still needs to be explored.

Hsa_circ_0119412 Contributes to Development of Retinoblastoma by Targeting miR-186-5p/ELK4 Axis.

Increasing evidences indicate the crucial role of circRNAs in tumorigenesis, but little is understood about their molecular mechanism in retinoblastoma (RB). This paper was designed for exploring the circ_0119412 function in cases with RB and the potential mechanism. RT-qPCR was utilized to ascertain circ_0119412 and miR-186-5p levels in RB tissues and cells, and western blotting was used to quantify ELK4 in RB cells. In addition, CCK-8 and scratch assays were carried out for evaluation of cell proliferation and migration, respectively. Apoptosis-related proteins levels (Bax and Bcl-2) were measure by western blotting. Tumor growth in vivo was detected utilizing xenograft tumor experiment. The targeting relationship between circ_0119412, miR-186-5p, and ELK4 was validated using a dual-luciferase reporter assay and an RNA immunoprecipitation (RIP) assay. In RB tissues and cells, Circ_0119412 and ELK4 expression were upregulated, while miR-186-5p expression was downregulated. In vitro assay revealed that downregulating circ_0119412 accelerated the cell apoptosis of RB cells and slowed down their migration and proliferation, and the in vivo assay indicated that circ_0119412 downregulation reduced the weight and volume of tumor in nude mice. In addition, miR-186-5p interference promoted the malignant behavior of RB cells, while ELK4 silencing showed an opposite trend. Mechanically, circ_0119412 can promote RB malignant phenotypes via miR-186-5p/ELK4 axis. Circ_0119412 was found to be upregulated in RB, and could accelerate the progression of RB via the miR-186-5p/ELK4 axis, indicating circ_0119412 may serve a promising clinical therapeutic target of RB.

Sequencing of RB1 Gene and In Silico Analysis in Western Algerian Population Affected by Retinablastoma

Retinoblastoma (RB) is an intraocular malignant tumour which occurs in children during the first months of life, with an incidence of 1 in 15,000 live births. Antioncogene RB1 located on chromosome 13q14.2, is at the origin of this pathology. For retinoblastoma development, two allele mutations of this gene are required. The aim of this study firstly, was to identify mutations that affect the RB1 gene in constitutional level, to detect early subject at risk or asymptomatic carriers and secondly to contribute on the understanding of the molecular pathogenesis. The study concerned 61 patients with retinoblastoma in Western Algeria. DNA from blood was used for amplification and gene sequencing. The results were completed by in-silico analysis using bio-informatic methods to know the mutation impact on the pRB1 protein function. Amplification and sequencing results gave nineteen different variations bases, including eight exonic changes: three missense mutations and five nonsense mutations located in exons 1,7,8,12,18,19,20 and 23. There are an important number of mutations located in twelve RB1 gene introns. These mutations were identified in germinal level for children with no family history of the disease. In conclusion, this study reported two new RB1 mutations in exons 1 and 7 among the eight identified. The mutations described in sporadic forms of retinoblastoma are transmissible forms in 13.11% of cases in our studied population. This study would improve role of genetic testing for management and family screening.

Prenatal ambient pesticide exposure and childhood retinoblastoma.

Retinoblastoma is a rare tumor of the retina, most commonly found in young children. Due to the rarity of this childhood cancer, few studies have been able to examine prenatal pesticide exposure as a risk factor. To examine the relationship between childhood retinoblastoma and prenatal exposure to pesticides through residential proximity to agricultural pesticide applications. We conducted a population-based case-control study using cases aged 5 and younger identified from the California Cancer Registry, and controls randomly selected from California birth certificates. Frequency matching cases to controls by age resulted in 221 cases of unilateral retinoblastoma and 114 cases of bilateral retinoblastoma, totaling 335 cases and 123,166 controls. Based on addresses from birth certificates we employed Pesticide Use Reports and land use information within a geographic information system approach to individually assess exposures to specific pesticides within 4000m of the residence reported on birth certificates. The associations between retinoblastoma (all types combined and stratified by laterality) and individual pesticides were expressed as odds ratios estimates obtained from unconditional logistic regression models including a single pesticide, and from a hierarchical logistic regression model including all pesticides. We found that exposures to acephate (OR: 1.70, 95% CI: 1.20, 2.41) and bromacil (OR: 1.87, 95% CI: 1.07, 3.26) were associated with increased risk for unilateral retinoblastoma. In addition to acephate, we found that pymetrozine (OR: 1.45, 95% CI: 1.00, 2.08) and kresoxim-methyl (OR: 1.60, 95% CI: 1.00, 2.56) were associated with retinoblastoma (all types combined). Our findings suggest that certain types of prenatal ambient pesticide exposure from residing near agricultural fields may play a role in the development of childhood retinoblastoma.

The role of maternal age & birth order on the development of unilateral and bilateral retinoblastoma: a multicentre study

Background/ObjectivesRetinoblastoma is a common childhood intraocular malignancy, the bilateral form of which most commonly results from a de novo germline pathogenic variant in the RB1 gene. Both advanced maternal age and decreasing birth order are known to increase the risk of de novo germline pathogenic variants, while the influence of national wealth is understudied. This cohort study aimed to retrospectively observe whether these factors influence the ratio of bilateral retinoblastoma cases compared to unilateral retinoblastoma, thereby inferring an influence on the development of de novo germline pathogenic variants in RB1.Subjects/MethodsData from 688 patients from 11 centres in 10 countries were analysed using a series of statistical methods.ResultsNo associations were found between advanced maternal age, birth order or GDP per capita and the ratio of bilateral to unilateral retinoblastoma cases (p values = 0.534, 0.201, 0.067, respectively), indicating that these factors do not contribute to the development of a de novo pathogenic variant.ConclusionsDespite a lack of a definitive control group and genetic testing, this study demonstrates that advanced maternal age, birth order or GDP per capita do not influence the risk of developing a bilateral retinoblastoma.

MicroRNA hsa-miR-657 promotes retinoblastoma malignancy by inhibiting peroxisome proliferator-activated receptor alpha expression.

Retinoblastoma is a familial inherited embryonic neuroretinal malignancy with a low survival rate and poor prognosis. Our study aimed to evaluate the potential interaction between microRNA miR-657 and the peroxisome proliferator-activated receptor alpha (PPARA) in retinoblastoma. Expression of miR-657 and PPARA was analyzed in retinoblastoma tissues and cells using RT-qPCR. Cell proliferation, apoptosis, and migration were measured in retinoblastoma cell lines, and xenografting experiments were performed using nude mice. Our study showed that miR-657 expression was markedly increased, whereas that of PPARA was markedly decreased in retinoblastoma. Additionally, PPARA knockdown enhanced the development of retinoblastoma. miR-657 enhanced the retinoblastoma tumorigenesis by directly inhibiting PPARA expression, suggesting that PPARA targeting by miR-657 facilitates retinoblastoma development by enhancing cell growth. This study provides novel insights into the miR-657- and PPARA-mediated mechanisms underlying retinoblastoma progression and suggests that the interaction between miR-657 and PPARA may serve as an effective target for therapeutic intervention.

PRB-Depleted Pluripotent Stem Cell Retinal Organoids Recapitulate Cell State Transitions of Retinoblastoma Development and Suggest an Important Role for pRB in Retinal Cell Differentiation.

Retinoblastoma (Rb) is a childhood cancer of the developing retina, accounting for up to 17% of all tumors in infancy. To gain insights into the transcriptional events of cell state transitions during Rb development, we established 2 disease models via retinal organoid differentiation of a pRB (retinoblastoma protein)-depleted human embryonic stem cell line (RB1-null hESCs) and a pRB patient-specific induced pluripotent (iPSC) line harboring a RB1 biallelic mutation (c.2082delC). Both models were characterized by pRB depletion and accumulation of retinal progenitor cells at the expense of amacrine, horizontal and retinal ganglion cells, which suggests an important role for pRB in differentiation of these cell lineages. Importantly, a significant increase in the fraction of proliferating cone precursors (RXRγ+Ki67+) was observed in both pRB-depleted organoid models, which were defined as Rb-like clusters by single-cell RNA-Seq analysis. The pRB-depleted retinal organoids displayed similar features to Rb tumors, including mitochondrial cristae aberrations and rosette-like structures, and were able to undergo cell growth in an anchorage-independent manner, indicative of cell transformation in vitro. In both models, the Rb cones expressed retinal ganglion and horizontal cell markers, a novel finding, which could help to better characterize these tumors with possible therapeutic implications. Application of Melphalan, Topotecan, and TW-37 led to a significant reduction in the fraction of Rb proliferating cone precursors, validating the suitability of these in vitro models for testing novel therapeutics for Rb.

LncRNA ZFPM2-AS1 promotes retinoblastoma progression by targeting microRNA miR-511-3p/paired box protein 6 (PAX6) axis

ABSTRACT Long non-coding RNAs (lncRNAs) have been shown to play crucial roles in retinoblastoma progression. In this study, we aimed to investigate the mechanism of lncRNA ZFPM2-AS1 (ZFPM2-AS1) in retinoblastoma progression. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and Western blotting assays were performed to determine the expression of lncRNA, microRNA (miRNA), mRNA, and protein. The changes in cell proliferation, apoptosis, and cell migration were assessed by functional experiments. The interaction between ZFPM2-AS1, miR-511-3p, and paired box protein 6 (PAX6) was confirmed by a luciferase assay. Our study found that ZFPM2-AS1 and PAX6 were upregulated, whereas miR-511-3p was downregulated in retinoblastoma. ZFPM2-AS1 inhibition decreased the viability and migration of retinoblastoma cells. We also found that ZFPM2-AS1 targets miR-511-3p to upregulate PAX6 in Y79 and SO-RB50 cells. Moreover, we demonstrated that inhibiting miR-511-3p reversed the negative effects of silencing ZFPM2-AS1 and PAX6 on retinoblastoma cell viability and migration. In conclusion, retinoblastoma development is regulated by the ZFPM2-AS1/511-3p/PAX6 axis.

LncRNA ZFPM2-AS1 Enhances Retinoblastoma Development by Targeting the miR-3612/NT5E Signaling Axis.

Background - Retinoblastoma (RB) is an intraocular malignancy usually observed in children. The zinc finger protein, FOG family member 2 (ZFPM2)-antisense RNA 1 (AS1), an anomalous long non-coding RNA, is detected in many cancers. This study aimed to evaluate the role and underlying mechanism of ZFPM2-AS1 in RB. Methods - ZFPM2-AS1, 5'-nucleotidase ecto (NT5E), and microRNA (miR)-3612 expression levels were determined in RB cells and tissues. Multiple experiments, including cell counting kit-8, 5'-bromo-2'-deoxyuridine, transwell, and enzyme-linked immunosorbent assays, were conducted to evaluate their effects on cell proliferation, migration, and apoptosis. Additionally, the ZFPM2-AS1/miR-3612/NT5E axis was validated using luciferase reporter, anti-AGO2 RNA immunoprecipitation, and RNA pull-down assays. Results - Overexpression of ZFPM2-AS1 and NT5E and downregulation of miR-3612 expression levels were observed in RB cells and tissues. Knockdown of ZFPM2-AS1 decreased the proliferation and migration of RB cells, while enhancing their apoptosis. The ZFPM2-AS1/miR-3612/NT5E axis was further supported by the negative correlation between miR-3612 expression levels and ZFPM2-AS1 or NT5E expression levels in RB tissues. Moreover, the miR-3612 inhibitor restored the inhibitory effect on the malignant behavior of RB cells by silencing ZFPM2-AS1. Furthermore, NT5E silencing phenocopied the effect of ZFPM2-AS1 silencing and abolished miR-3612 inhibitor-induced stimulation of the malignant behavior of RB cells. Conclusion - These results suggest that by targeting the miR-3612/NT5E axis, ZFPM2-AS1 stimulates the proliferation and migration of RB cells, while inhibiting their apoptosis. Therefore, ZFPM2-AS1 may be a promising therapeutic target associated with RB development.

Hsa_circ_0000527 Downregulation Suppresses the Development of Retinoblastoma by Modulating the miR-27a-3p/HDAC9 Pathway

ABSTRACT Background Accumulating evidence indicates that the progression of retinoblastoma (RB) may involve circRNA dysfunction. We aimed to disclose the role of hsa_circ_0000527 and its potential functional mechanism in RB. Methods The expression of hsa_circ_0000527, miR-27a-3p and histone deacetylase 9 (HDAC9) mRNA was monitored using quantitative real-time polymerase chain reaction (qPCR). Functional assays, including cell proliferation and apoptosis, were investigated using cell counting kit-8 (CCK-8) assay, colony formation assay and flow cytometry assay. The expression of apoptosis-associated proteins and HDAC9 protein was detected by western blot. The targeting relationship between miR-27a-3p and hsa_circ_0000527 or HDAC9 was verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Besides, Xenograft models were constructed to confirm the effect of hsa_circ_0000527 in vivo. Results Hsa_circ_0000527 and HDAC9 were upregulated, while miR-27a-3p was downregulated in RB tissues and cells. Hsa_circ_0000527 downregulation repressed RB cell proliferation and induced RB cell apoptosis. MiR-27a-3p was a target of hsa_circ_0000527, and hsa_circ_0000527 suppressed the expression of miR-27a-3p. MiR-27a-3p inhibition reversed the role of hsa_circ_0000527 downregulation. In addition, HDAC9 was a target of miR-27a-3p, and hsa_circ_0000527 indirectly regulated HDAC9 expression by targeting miR-27a-3p. MiR-27a-3p restoration inhibited RB cell proliferation and promoted apoptosis, which was reversed by HDAC9 overexpression. Hsa_circ_0000527 downregulation could inactivate the PI3K/AKT pathway. Moreover, hsa_circ_0000527 downregulation blocked tumor growth rate in vivo. Conclusion hsa_circ_0000527 downregulation blocked the progression of RB by regulating the miR-27a-3p/HDAC9 pathway, which might be associated with the inactivation of the PI3K/AKT pathway.

Single-cell transcriptome profiling reveals intratumoural heterogeneity and malignant progression in retinoblastoma

Retinoblastoma is a childhood retinal tumour that is the most common primary malignant intraocular tumour. However, it has been challenging to identify the cell types associated with genetic complexity. Here, we performed single-cell RNA sequencing on 14,739 cells from two retinoblastoma samples to delineate the heterogeneity and the underlying mechanism of retinoblastoma progression. Using a multiresolution network-based analysis, we identified two major cell types in human retinoblastoma. Cell trajectory analysis yielded a total of 5 cell states organized into two main branches, and the cell cycle-associated cone precursors were the cells of origin of retinoblastoma that were required for initiating the differentiation and malignancy process of retinoblastoma. Tumour cells differentiation reprogramming trajectory analysis revealed that cell-type components of multiple tumour-related pathways and predominantly expressed UBE2C were associated with an activation state in the malignant progression of the tumour, providing a potential novel “switch gene” marker during early critical stages in human retinoblastoma development. Thus, our findings improve our current understanding of the mechanism of retinoblastoma progression and are potentially valuable in providing novel prognostic markers for retinoblastoma.

Parental age and retinoblastoma-a retrospective study of demographic data and genetic analysis.

To determine the association between the parental age gap and the absolute parental age with the risk of retinoblastoma (RB) development in an offspring. RB individuals diagnosed between March 2013 and December 2019 in a single tertiary eye care centre were included. We recorded the demographic data, parental age and RB1 gene mutation status in the patient's tumour, blood and the parental blood. We categorised RB1 mutation inheritance as sporadic RB with somatic mutations (only present in tumour), heritable RB with de novo (present in patient's blood) and familial (present in patient and parents' blood) germline mutations. The statistical significance was confirmed by Fisher's exact/Chi-square test. Out of 259 RB patients, 247 were included in our study. Heritable RB with de novo germline mutations was significantly less common (p value: 0.0387; 95% CI: 0.2676-0.9329) and sporadic RB with somatic mutations was more common (p value: 0.0545; 95% CI: 1.025-3.39), if the parental age gap was <10 years. There were increased odds of a heritable RB with de novo germline mutation with an increase in paternal age and this was more intensified when combined with parental age gap of more than ≥10 years. The heritable RB with de novo germline mutations significantly increased as maternal age progressed, only when it was adjusted to ≥10 years parental age gap (p value: 0.0262; 95% CI: 1.26-17.91). An increased parental age gap and increased paternal age are independent risk factors for the development of heritable RB with de novo germline mutation.

The Effects of Breastfeeding on Retinoblastoma Development: Results from an International Multicenter Retinoblastoma Survey.

Simple SummaryBreastfeeding has been shown to lower the risk of oncogenesis in many pediatric cancers, with longer periods of breastfeeding having the most protective effect. However, an association has not yet been determined for the consequence or benefit of breastfeeding in retinoblastoma (RB), the most common intraocular malignancy of childhood affecting 8000 children worldwide each year. Herein, we aimed to understand the role of breastfeeding in the severity of development of nonhereditary RB, specifically its relationship to age at diagnosis, ocular prognosis, and extraocular involvement. Our analysis of 344 patients indicated that neither breastfeeding nor formula feeding was associated with differences in age at diagnosis, ocular prognosis, or extraocular involvement. More research elucidating the factors affecting the development of RB is warranted both to understand the pathophysiology of tumor development and to develop clinical recommendations for preventive care.The protective effects of breastfeeding on various childhood malignancies have been established but an association has not yet been determined for retinoblastoma (RB). We aimed to further investigate the role of breastfeeding in the severity of nonhereditary RB development, assessing relationship to (1) age at diagnosis, (2) ocular prognosis, measured by International Intraocular RB Classification (IIRC) or Intraocular Classification of RB (ICRB) group and success of eye salvage, and (3) extraocular involvement. Analyses were performed on a global dataset subgroup of 344 RB patients whose legal guardian(s) consented to answer a neonatal questionnaire. Patients with undetermined or mixed feeding history, family history of RB, or sporadic bilateral RB were excluded. There was no statistically significant difference between breastfed and formula-fed groups in (1) age at diagnosis (p = 0.20), (2) ocular prognosis measures of IIRC/ICRB group (p = 0.62) and success of eye salvage (p = 0.16), or (3) extraocular involvement shown by International Retinoblastoma Staging System (IRSS) at presentation (p = 0.74), lymph node involvement (p = 0.20), and distant metastases (p = 0.37). This study suggests that breastfeeding neither impacts the sporadic development nor is associated with a decrease in the severity of nonhereditary RB as measured by age at diagnosis, stage of disease, ocular prognosis, and extraocular spread. A further exploration into the impact of diet on children who develop RB is warranted.

Molecular alterations in retinoblastoma beyond RB1

Retinoblastoma is the most common malignant ocular tumor in children. Although RB1 alterations are most frequently involved in the etiology of retinoblastoma, candidate driver events and somatic alterations leading to cell transformation, tumor onset and progression remain poorly understood. In this study, we identified novel genomic alterations in tumors with a panel of 160 genes. Sanger sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA) were initially performed for identifying patients without apparent RB1 alterations in blood DNA. Subsequently, NGS analyses of 24 paired (blood/tumor) samples of these patients were carried out for identifying somatic mutations and copy number variation in RB1 and other 159 genes. One novel pathogenic RB1 mutation and seven novel VUS were identified as well as 90 novel pathogenic mutations in 61 other genes. Twenty-three genes appeared exclusively mutated in tumors without altered RB1 alleles and three frequently affected biological pathways while five other tumors did not show pathogenic RB1 alterations or SNV/indels in 159 other genes. Curiously, deletion of GATA2, AKT1, ARID1A, DNMT3A, MAP2K2, MEN1, MTOR, PTCH1 and SUFU (in homo- or heterozygosity) were exclusively found in these tumors when compared to those with any pathogenic alterations, probably indicating genes that might be essential for the development of retinoblastoma regardless of a functional RB1. Identification of genes associated with retinoblastoma will contribute to understanding presently unknown aspects of this malignancy, which might be essential for its initiation and progression, as well as providing valuable molecular markers.

Weighted genes associated with the progression of retinoblastoma: Evidence from bioinformatic analysis

Mechanisms underlying the development of malignant retinoblastoma (RB) remain largely unknown. The purpose of this study was to identify weighted genes that are associated with the progression of RB and to assess the usefulness of bioinformatic analysis in RB research. Bioinformatic analysis was performed to construct weighted gene co-expression and protein-protein interaction (PPI) networks and to predict long non-coding RNA (lncRNA)-microRNA (miRNA)-mRNA regulatory networks. RNA extracted from RB and adjacent retinal tissue was used to validate the results obtained from bioinformatic analysis, using a semi-quantitative PCR (qPCR) assay. Twenty-one modules were generated from 5000 most variably expressed genes. Both the light-yellow and red modules were significantly associated with the cellular anaplastic grade of RB. The genes clustered in the light-yellow module included protocadherin beta (PCDHBs) family members. The red module included 5 hub genes involved in cell division. According to the hypothesis that lncRNA may serve as a competing endogenous RNA (ceRNA) for miRNAs and modulates mRNA expression, a network was constructed between lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and cell division-related mRNAs. PCR analysis using 23 tumor tissues and 5 adjacent retinal tissue showed increased expression of PCDHB5 in tumor samples, and supported the predicted upregulation of mitotic checkpoint serine/threonine kinase (BUB1) by MALAT1 via miR-495-3p. Our study highlights the importance of bioinformatic analysis in identifying potential markers and mechanisms associated with the malignant transformation of RB, and provides evidence to suggest that PCDHB5 and the ceRNA regulatory network of MALAT1/miR-495-3p/BUB1 are involved in the progression of RB.

Advances in the role of autophagy in the development of retinoblastoma.

Autophagy is a feedback regulatory mechanism of cells to external stress, which helps cells to adapt to changes in physiological conditions and environmental stress. Autophagy possesses a variety of target genes that control a wide range of signaling pathways. Maintenance of an appropriate level of autophagy is essential for the growth, metastasis and characteristics of tumors. Retinoblastoma (RB) is the most common primary intraocular malignant tumor found in the eyes of children following exposure to extreme environmental factors, such as mitochondrial defects, oxidative stress and excessive autophagy; this leads to the development of DNA damage and progressive loss of the function of the eye, which results in the occurrence of RB. Recent studies have documented the involvement of autophagy in the transformation, occurrence and metastasis of RB. High or low levels of autophagy exert notably promotive or repressive effects on the development, invasion, drug resistance and survival of RB, respectively. The present review reports the research progress on the association between autophagy and RB.