Management of retinoblastoma: opportunities and challenges

Advancements in the diagnosis, prognosis, and treatment of retinoblastoma

Retinoblastoma (RB) is a prevalent primitive intraocular malignancy in children, particularly in those younger than age 3 years. RB is caused by mutations in the RB1 gene. In developing countries, mortality rates for this type of cancer are still high, whereas industrialized countries have achieved a survival rate of >95%-98%. Untreated, the condition can be fatal, underscoring the importance of early diagnosis. The existing treatments primarily consist of surgery, radiotherapy, and chemotherapy. The detrimental effects of radiation and chemotherapeutic drugs have been documented as factors that contribute to increased mortality rates and negatively affect the quality of life for patients. MicroRNA (miRNA), a type of noncoding RNA, exerts a substantial influence on RB development and the emergence of treatment resistance by regulating diverse cellular processes. This review highlights recent developments in the involvement of miRNAs in RB. This encompasses the clinical significance of miRNAs in the diagnosis, prognosis, and treatment of RB. Additionally, this paper examines the regulatory mechanisms of miRNAs in RB and explores potential therapeutic interventions. This paper provides an overview of the current and emerging treatment options for RB, focusing on recent studies investigating the application of different types of nanoparticles for the diagnosis and treatment of this condition.

Retinoblastoma: An update on genetic origin, classification, conventional to next-generation treatment strategies

The most prevalent paediatric vision-threatening medical condition, retinoblastoma (RB), has been a global concern for a long time. Several conventional therapies, such as systemic chemotherapy and focal therapy, have been used for curative purposes; however, the search for tumour eradication with the least impact on surrounding tissues is still ongoing. This review focuses on the genetic origin, classification, conventional treatment modalities, and their combination with nano-scale delivery systems for active tumour targeting. In addition, the review also delves into ongoing clinical trials and patents, as well as emerging therapies such as gene therapy and immunotherapy for the treatment of RB. Understanding the role of genetics in the development of RB has refined its treatment strategy according to the genetic type. New approaches such as nanostructured drug delivery systems, galenic preparations, nutlin-3a, histone deacetylase inhibitors, N-MYC inhibitors, pentoxifylline, immunotherapy, gene therapy, etc. discussed in this review, have the potential to circumvent the limitations of conventional therapies and improve treatment outcomes for RB. In summary, this review highlights the importance and need for novel approaches as alternative therapies that would ultimately displace the shortcomings associated with conventional therapies and reduce the enucleation rate, thereby preserving global vision in the affected paediatric population.

An Update on Emergent Nano-Therapeutic Strategies against Pediatric Brain Tumors

Pediatric brain tumors are the major cause of pediatric cancer mortality. They comprise a diverse group of tumors with different developmental origins, genetic profiles, therapeutic options, and outcomes. Despite many technological advancements, the treatment of pediatric brain cancers has remained a challenge. Treatment options for pediatric brain cancers have been ineffective due to non-specificity, inability to cross the blood-brain barrier, and causing off-target side effects. In recent years, nanotechnological advancements in the medical field have proven to be effective in curing challenging cancers like brain tumors. Moreover, nanoparticles have emerged successfully, particularly in carrying larger payloads, as well as their stability, safety, and efficacy monitoring. In the present review, we will emphasize pediatric brain cancers, barriers to treating these cancers, and novel treatment options.

Enhanced anti-tumor activity of transferrin/folate dual-targeting magnetic nanoparticles using chemo-thermo therapy on retinoblastoma cancer cells Y79

Malignant neoplasms are one of the main causes of death, especially in children, on a global scale, despite strenuous efforts made at advancing both diagnostic and therapeutic modalities. In this regard, a new nanocarrier Vincristine (VCR)-loaded Pluronic f127 polymer-coated magnetic nanoparticles conjugated with folic acid and transferrin (PMNP-VCR-FA-TF) were synthesized and characterized by various methods. The cytotoxicity of these nanoparticles was evaluated in vitro and ex vivo conditions. The in vitro anti-tumor effect of the nanoparticles was evaluated by colony formation assay (CFA) and reactive oxygen species (ROS) in Y79 cell line. The results showed that nanoparticles with two ligands conferred greater toxicity toward Y79 cancer cells than ARPE19 normal cells. Under an alternating magnetic field (AMF), these nanoparticles demonstrated a high specific absorption rate. The CFA and ROS results indicated that the AMF in combination with PMNP-VCR-FA-TF conferred the highest cytotoxicity toward Y79 cells compared with other groups (P < 0.05). PMNP-VCR-FA-TF could play an important role in converting externally applied radiofrequency energy into heat in cancer cells. The present study confirmed that dual targeting chemo-hyperthermia using PMNP-VCR-FA-TF was significantly more effective than hyperthermia or chemotherapy alone, providing a promising platform for precision drug delivery as an essential component in the chemotherapy of retinoblastoma.

Nanoparticle-based delivery systems as emerging therapy in retinoblastoma: recent advances, challenges and prospects

Retinoblastoma is the most common intraocular malignancy in children. The treatment of this rare disease is still challenging in developing countries due to delayed diagnosis. The current therapies comprise mainly surgery, radiotherapy and chemotherapy. The adverse effects of radiation and chemotherapeutic drugs have been reported to contribute to the high mortality rate and affect patients' quality of life. The systemic side effects resulting from the distribution of chemotherapeutic drugs to non-cancerous cells are enormous and have been recognized as one of the reasons why most potent anticancer compounds fail in clinical trials. Nanoparticulate delivery systems have the potential to revolutionize cancer treatment by offering targeted delivery, enhanced penetration and retention effects, increased bioavailability, and an improved toxicity profile. Notwithstanding the plethora of evidence on the beneficial effects of nanoparticles in retinoblastoma, the clinical translation of this carrier is yet to be given the needed attention. This paper reviews the current and emerging treatment options for retinoblastoma, with emphasis on recent investigations on the use of various classes of nanoparticles in diagnosing and treating retinoblastoma. It also presents the use of ligand-conjugated and smart nanoparticles in the active targeting of anticancer and imaging agents to the tumour cells. In addition, this review discusses the prospects and challenges in translating this nanocarrier into clinical use for retinoblastoma therapy. This review may provide new insight for formulation scientists to explore in order to facilitate the development of more effective and safer medicines for children suffering from retinoblastoma.

miRNAs as potential game-changers in retinoblastoma: Future clinical and medicinal uses

Retinoblastoma (RB) is a rare tumor in children, but it is the most common primitive intraocular malignancy in childhood age, especially those below three years old. The RB gene (RB1) undergoes mutations in individuals with RB. Although mortality rates remain high in developing countries, the survival rate for this type of cancer is greater than 95-98% in industrialized countries. However, it is lethal if left untreated, so early diagnosis is essential. As a non-coding RNA, miRNA significantly impacts RB development and treatment resistance because it can control various cellular functions. In this review, we illustrate the recent advances in the role of miRNAs in RB. That includes the clinical importance of miRNAs in RB diagnosis, prognosis, and treatment. Moreover, the regulatory mechanisms of miRNAs in RB and therapeutic interventions are discussed.

Intraocular siRNA Delivery Mediated by Penetratin Derivative to Silence Orthotopic Retinoblastoma Gene

Gene therapy brings a ray of hope for inherited ocular diseases that may cause severe vision loss and even blindness. However, due to the dynamic and static absorption barriers, it is challenging to deliver genes to the posterior segment of the eye by topical instillation. To circumvent this limitation, we developed a penetratin derivative (89WP)-modified polyamidoamine polyplex to deliver small interference RNA (siRNA) via eye drops to achieve effective gene silencing in orthotopic retinoblastoma. The polyplex could be spontaneously assembled through electrostatic and hydrophobic interactions, as demonstrated by isothermal titration calorimetry, and enter cells intactly. In vitro cellular internalization revealed that the polyplex possessed higher permeability and safety than the lipoplex composed of commercial cationic liposomes. After the polyplex was instilled in the conjunctival sac of the mice, the distribution of siRNA in the fundus oculi was significantly increased, and the bioluminescence from orthotopic retinoblastoma was effectively inhibited. In this work, an evolved cell-penetrating peptide was employed to modify the siRNA vector in a simple and effective way, and the formed polyplex interfered with intraocular protein expression successfully via noninvasive administration, which showed a promising prospect for gene therapy for inherited ocular diseases.

Nanotechnology for Pediatric Retinoblastoma Therapy

Retinoblastoma is a rare, sometimes hereditary, pediatric cancer. In high-income countries this disease has a survival rate approaching 100%, while in low- and middle-income countries the prognosis is fatal for about 80% of cases. Depending on the stage of the disease, different therapeutic protocols are applied. In more advanced forms of the disease, surgical removal of the entire globe and its intraocular contents (enucleation) is, unfortunately, necessary, whereas in other cases, conventional chemotherapy is normally used. To overcome the side-effects and reduced efficacy of traditional chemotherapic drugs, nanodelivery systems that ensure a sustained drug release and manage to reach the target site have more recently been developed. This review takes into account the current use and advances of nanomedicine in the treatment of retinoblastoma and discusses nanoparticulate formulations that contain conventional drugs and natural products. In addition, future developments in retinoblastoma treatment are discussed.

Drug Delivery Challenges and Current Progress in Nanocarrier-Based Ocular Therapeutic System

Drug instillation via a topical route is preferred since it is desirable and convenient due to the noninvasive and easy drug access to different segments of the eye for the treatment of ocular ailments. The low dose, rapid onset of action, low or no toxicity to the local tissues, and constrained systemic outreach are more prevalent in this route. The majority of ophthalmic preparations in the market are available as conventional eye drops, which rendered <5% of a drug instilled in the eye. The poor drug availability in ocular tissue may be attributed to the physiological barriers associated with the cornea, conjunctiva, lachrymal drainage, tear turnover, blood-retinal barrier, enzymatic drug degradation, and reflex action, thus impeding deeper drug penetration in the ocular cavity, including the posterior segment. The static barriers in the eye are composed of the sclera, cornea, retina, and blood-retinal barrier, whereas the dynamic barriers, referred to as the conjunctival and choroidal blood flow, tear dilution, and lymphatic clearance, critically impact the bioavailability of drugs. To circumvent such barriers, the rational design of the ocular therapeutic system indeed required enriching the drug holding time and the deeper permeation of the drug, which overall improve the bioavailability of the drug in the ocular tissue. This review provides a brief insight into the structural components of the eye as well as the therapeutic challenges and current developments in the arena of the ocular therapeutic system, based on novel drug delivery systems such as nanomicelles, nanoparticles (NPs), nanosuspensions, liposomes, in situ gel, dendrimers, contact lenses, implants, and microneedles. These nanotechnology platforms generously evolved to overwhelm the troubles associated with the physiological barriers in the ocular route. The controlled-drug-formulation-based strategic approach has considerable potential to enrich drug concentration in a specific area of the eye.

Update on the Treatment of Retinoblastoma

Retinoblastoma (Rb) is the most common pediatric ocular malignancy and accounts for 2% of all childhood cancers. Rb is initiated by a mutation of the RB1 tumor suppressor gene and occurs in 2 forms: 1) unilateral and unifocal, characterized by a single tumor in 1 eye, and 2) bilateral or unilateral, multifocal Rb with multiple tumor foci in 1 or both eyes. Rb is a disease of young children and if left untreated can result in visual morbidity as well as systemic mortality. Fortunately, because of the greater availability of genetic testing and earlier diagnosis, novel targeted therapies, and multimodal treatment approaches, disease-free survival rates and visual prognoses have improved dramatically. Current efforts to expand the accessibility of the newest Rb treatments aim to improve Rb outcomes worldwide. In this article, we will review the clinical presentation, diagnosis, and management of Rb, with a focus on the newest treatment approaches.

Recent Developments in Nanomedicine for Pediatric Cancer

Cancer is the second biggest cause of death in children in the US. With the development of chemotherapy, there has been a substantial increase in the overall survival rate in the last 30 years. However, the overall mortality rate in children with cancer remains 25%, and many survivors experience a decline in overall quality of life and long-term adverse effects caused by treatments. Although cancer cells share common characteristics, pediatric cancers are different from adult cancers in their prevalence, mutation load, and drug response. Therefore, there is an urgent unmet need to develop therapeutic approaches specifically designed for children with cancer. Nanotechnology can potentially overcome the deficiencies of conventional methods of administering chemotherapy and ultimately improve clinical outcomes. The nanoparticle-based drug delivery systems can decrease the toxicity of therapy, provide a sustained or controlled drug release, improve the pharmacokinetic properties of loading contents, and achieve a targeted drug delivery with achievable modifications. Furthermore, therapeutic approaches based on combining nanoformulated drugs with novel immunotherapeutic agents are emerging. In this review, we discussed the recently developed nanotechnology-based strategies for treating blood and solid pediatric cancers.

Multi-Functionalized Nanomaterials and Nanoparticles for Diagnosis and Treatment of Retinoblastoma

Retinoblastoma is a rare type of cancer, and its treatment, as well as diagnosis, is challenging, owing to mutations in the tumor-suppressor genes and lack of targeted, efficient, cost-effective therapy, exhibiting a significant need for novel approaches to address these concerns. For this purpose, nanotechnology has revolutionized the field of medicine with versatile potential capabilities for both the diagnosis, as well as the treatment, of retinoblastoma via the targeted and controlled delivery of anticancer drugs via binding to the overexpressed retinoblastoma gene. Nanotechnology has also generated massive advancements in the treatment of retinoblastoma based on the use of surface-tailored multi-functionalized nanocarriers; overexpressed receptor-based nanocarriers ligands (folate, galactose, and hyaluronic acid); lipid-based nanocarriers; and metallic nanocarriers. These nanocarriers seem to benchmark in mitigating a plethora of malignant retinoblastoma via targeted delivery at a specified site, resulting in programmed apoptosis in cancer cells. The effectiveness of these nanoplatforms in diagnosing and treating intraocular cancers such as retinoblastoma has not been properly discussed, despite the increasing significance of nanomedicine in cancer management. This article reviewed the recent milestones and future development areas in the field of intraocular drug delivery and diagnostic platforms focused on nanotechnology.

Laser-induced plasmon-mediated treatment of retinoblastoma in viscous vitreous phantom

Retinoblastoma (RB) is a rare form of cancer of the retina most prevalent in young children. We successfully show that laser-induced cell disruption, mediated by gold plasmonic nanoparticle (NP), is a potential and efficient therapy to kill the cancerous cells. The proof of concept is demonstrated in vitro on cultured Y79 RB cancer cells with a nanosecond laser at 527 nm, for both attached cells at the bottom of a Petri dish and for floating, clustered cells in a viscous vitreous phantom comprised of hyaluronan. We report a cellular death of 82% after irradiation in classic culture medium and a cellular death of 98% in vitreous phantom, for similar number of NPs in each sample. It is found that the NPs efficiently penetrate the floating Y79 clusters cells in the vitreous phantom, leading to a cellular death of over 85% even within the centre of the aggregates. The proposed treatment technique is based on a similar nanosecond laser used to eliminate floaters in the vitreous, but with much lower (100-1000 times) fluences of 20 J cm^-2 .

Magnetic Hyperthermia in Y79 Retinoblastoma and ARPE-19 Retinal Epithelial Cells: Tumor Selective Apoptotic Activity of Iron Oxide Nanoparticle

Purpose

To evaluate selective apoptosis of Y79 retinoblastoma versus ARPE-19 retinal pigment epithelial cells by using different doses of dextran-coated iron oxide nanoparticles (DCIONs) in a magnetic hyperthermia paradigm.

Methods

Y79 and ARPE-19 cells were exposed to different concentrations of DCIONs, namely, 0.25, 0.5, 0.75, and 1 mg/ml. After 2 hours of incubation, cells were exposed to a magnetic field with a frequency of 250 kHz and an amplitude of 4 kA/m for 30 minutes to raise the cellular temperature between 42 and 46°C. Y79 and ARPE-19 cells incubated with DCION without magnetic field exposure were used as controls. Cell viability and apoptosis were assessed at 4, 24, and 72 hours after hyperthermia treatment.

Results

At 4 hours following magnetic hyperthermia, cell death for Y79 cells was 1%, 8%, 17%, and 17% for 0.25, 0.5, 0.75 and 1 mg/ml of DCION, respectively. Cell death increased to 47%, 59%, 70%, and 75% at 24 hours and 16%, 45%, 50%, and 56% at 72 hours for 0.25, 0.5, 0.75, and 1 mg/ml of DCIONs, respectively. Magnetic hyperthermia did not have any significant toxic effects on ARPE-19 cells at all DCION concentrations, and minimal baseline cytotoxicity of DCIONs on Y79 and ARPE-19 cells was observed without magnetic field activation. Gene expression profiling showed that genes involved in FAS and tumor necrosis factor alpha signaling pathways were activated in Y79 cells following hyperthermia. Caspase 3/7 activity in Y79 cells increased following treatment, consistent with the activation of caspase-mediated apoptosis and loss of cell viability by magnetic hyperthermia.

Conclusion

Magnetic hyperthermia using DCIONs selectively kills Y79 cells at 0.5 mg/ml or higher concentrations via the activation of apoptotic pathways.

Translational Relevance

Magnetic hyperthermia using DCIONs might play a role in targeted management of retinoblastoma.

Biodegradable reduction-responsive polymeric micelles for enhanced delivery of melphalan to retinoblastoma cells

Melphalan (MEL) is an effective chemotherapeutic agent for treatment of retinoblastoma (Rb) which is the most common childhood malignancy. However, the inherent cardiopulmonary toxicity and hazardous integration limit its therapeutic effect on RB. N-Acetylheparosan (AH), a natural heparin-like polysaccharide in mammals with long circulation effect and good biocompatibility, was linked by d-α-tocopherol acid succinate (VES) via and cystamine (CYS) to synthesize reduction-responsive N-acetylheparosan-CYS-Vitamin E succinate (AHV) copolymers. In addition, CYS was replaced by adipic acid dihydrazide (ADH) to obtain a control of non-reduction-responsive polymers N-acetylheparosan-ADH-Vitamin E succinate (ADV). MEL-loaded AHV micelles (MEL/AHV) as well as ADV micelles (MEL/ADV) were prepared with small particle size and high drug loading content. In vitro drug release showed that MEL/AHV micelles presented obvious reduction-triggered release behavior compared with MEL/ADV. In vitro antitumor effects were investigated using WERI-Rb-1 retinoblastoma cells. Cytotoxicity experiments showed that the IC₅₀ of MEL/AHV was significantly lower than that of free MEL and MEL/ADV, suggesting that MEL/AHV enhanced the cytotoxicity against retinoblastoma cells. Furthermore, MEL/AHV micelles were more easily uptaken by multiple pathways compared with MEL/ADV and free MEL. Therefore, MEL/AHV might be a potential delivery system for enhanced delivery of melphalan to Rb cells.

Comparison of ocular pharmacokinetics of etoposide and its nanoemulsion after subtenon administration in rabbits

Background Subtenon anticancer drugs are given as an adjunct to systemic chemotherapy for conditions like retinoblatoma. This study evaluated the ocular kinetics of nano-emulsion formulation of etoposide (NanoEt) and compared it with an equal dose of commercially available alcohol-based etoposide formulation in healthy rabbits. Methods A nanoemulsion formulation of NanoEt was developed and then evaluated for its ocular kinetics by subtenon administration in healthy rabbits. After the sterile subtenon administration of the drug, the eyes were enucleated after CO2 euthanasia at time intervals of 2 h, 6 h, 12 h, and 24 h, and ocular tissues, blood, and plasma were separated. The concentration of etoposide in the ocular tissues and blood was quantified using liquid chromatography tandem mass spectrometry (LC MS/MS). Results This study found that subtenon injection of NanoEt showed 24 times higher concentration in rabbit retina compared to an equal dose of conventional marketed formulation. Based on the ocular tissue bioavailability calculations (AUC0-24), the present study revealed that the formulation enhanced 90% ocular bioavailability of etoposide, when it was injected in the form of nano-emulsion in most of the tissues. Conclusions NanoEt has better bioavailability compared to the commercial alcohol-based formulation for subtenon injection. Low systemic exposure showed further advantage for its projected use in retinoblastoma (Rb) as an adjunct therapy. Further studies in Rb animal models are required to evaluate its safety and efficacy, for its clinical utility.

Co-delivery of miR-181a and melphalan by lipid nanoparticles for treatment of seeded retinoblastoma

Melphalan is an efficient chemotherapeutic agent that is currently used to treat retinoblastoma (Rb); however, the inherent risk of immunogenicity and the hazardous integration of this drug in healthy cells is inevitable. MicroRNAs are short non-coding single-stranded RNAs that affect a vast range of biological processes. Previously, we focused on the regulatory role of miR-181a during cancer development and progression. In this manuscript, 171 nm switchable lipid nanoparticles (LNP) co-delivered melphalan and miR-181a with encapsulation efficiencies of 93%. Encapsulation of melphalan in LNP significantly improved its therapeutic efficiency. Gene analysis shows that miR-181a decreases the expression of anti-proliferative gene MAPK1 and anti-apoptotic gene Bcl-2, but significantly increased the expression of pro-apoptotic gene BAX. Our results suggest that the two agents have a complementary effect in reducing the viability of cultured Rb cells (primary and cell line) and decreasing Rb cell counts in an in-vivo xenograft Rb model in rats. Our results suggest that the proposed co-delivery technique significantly increases the therapeutic impact, allows for lower administration of melphalan, and consequently, could minimize the cytotoxic side-effects of this drug.

Hypoxia inhibits growth, proliferation, and increases response to chemotherapy in retinoblastoma cells

Retinoblastoma is a malignant tumor of the retina and the most frequent intraocular cancer in children. Low oxygen tension (hypoxia) is a common phenomenon in advanced retinoblastomas, but its biological effect on retinoblastoma growth is not clearly understood. Here we studied how hypoxia altered retinoblastoma gene expression and modulated growth and response to chemotherapy. The hypoxic marker lysyl oxidase (LOX) was expressed in 8 of 12 human retinoblastomas analyzed by immunohistochemistry, suggesting that a hypoxic microenvironment is present in up to two thirds of the cases. WERI Rb1 and Y79 retinoblastoma lines were exposed to 1% or 5% pO₂, cobalt chloride (CoCl₂), or to normoxia (21% pO₂) for up to 8 days. Both 1% and 5% pO₂ inhibited growth of both lines by more than 50%. Proliferation was reduced by 25-50% when retinoblastoma cells were exposed to 1% vs 21% pO₂, as determined by Ki67 assay. Surprisingly, Melphalan, Carboplatin, and Etoposide produced greater reduction in growth and survival of hypoxic cells than normoxic ones. Gene expression profile analysis of both lines, exposed for 48 h to 1%, 5%, or 21% pO₂, showed that glycolysis and glucose transport were the most up-regulated pathways, whereas oxidative phosphorylation was the most down-regulated pathway in hypoxia as compared to normoxia. These data support a role for hypoxia in suppressing growth, proliferation, and enhancing response of retinoblastoma cells to chemotherapy, possibly by impairing energy production through activation of glycolysis and inhibition of mitochondrial respiration. Targeting glucose metabolism or enhancing delivery of chemotherapeutic agents to hypoxic regions may improve treatment of advanced retinoblastomas.

Epidemiological Characteristics of Retinoblastoma in Children Attending Almouassat University Hospital, Damascus, Syria, 2012-2016

Retinoblastoma (Rb) is a malignant tumor that originates from the developing retina. Diagnosis is based on clinical signs and symptoms and usually children under the age of five years are affected. Early diagnosis and treatment of Rb and non-ocular tumors can reduce morbidity and increase longevity. Treatment in the early stages may allow a good prognosis and salvage of visual function.The aim of this study is to present descriptive epidemiological aspects of retinoblastomas in children seen at Almouassat University Hospital (AUH) in Damascus, Syria from 1 January 2012 to 31 October 2016In this retrospective, observational hospital survey, medical records of 37 retinoblastoma cases were reviewed. The male/female (M/F) ratio was 1.6. The most frequent presenting sign was leukocoria (56.7%) and 81% of cases were diagnosed between the ages of 4 months and 3 years. More than 73% of cases were diagnosed early at stages I and II.

Diffuse anterior retinoblastoma: current concepts

Diffuse anterior retinoblastoma is a rare variant of retinoblastoma seeding in the area of the vitreous base and anterior chamber. Patients with diffuse anterior retinoblastoma are older than those with the classical types, with the mean age being 6.1 years. The original cells of diffuse anterior retinoblastoma are supposed to be cone precursor. Patients most commonly present with pseudouveitis, pseudohypopyon, and increased intraocular pressure. The retina under fundus examination is likely to be normal, and the clinical features mimic the inflammation progress, which can often lead to misdiagnosis. The published diffuse anterior retinoblastoma cases were diagnosed after fine-needle aspiration biopsy running the potential risk of inducing metastasis. The most common treatment for diffuse anterior retinoblastoma is enucleation followed by systematic chemotherapy according to the patient’s presentation and clinical course. This review summarizes the recent advances in etiology (including tumorigenesis and cell origin), pathology, diagnosis, differential diagnosis, and new treatment. The challenges of early diagnosis and prospects are also discussed.