Investigation of the methylation changes in the promoter region of RB1 gene in retinoblastoma: Unraveling the epigenetic puzzle in retinoblastoma.

Retinoblastoma is an infrequent neoplasm that arises during childhood from retinal nerve cells and is attributed to the biallelic inactivation of the RB1 gene. In conjunction with anatomical anomalies, it is widely acknowledged that epigenetic modifications play a significant role in the pathogenesis of cancer. The association between methylation of the RB1 gene promoter and tumor formation has been established; however, there is currently no scholarly evidence to substantiate the claim that it is responsible for the inheritance of retinoblastoma. The initial hypothesis posited for this work was that familial retinoblastoma disease would be similarly observed in cases with RB1 promotor gene methylation, akin to RB1 mutations. The RB1 gene promoter region was subjected to methylation screening using real-time PCR in individuals diagnosed with familial retinoblastoma but lacking RB1 mutations. The study involved a comparison of the germline methylation status of the RB1 gene in the peripheral blood samples of 50 retinoblastoma patients and 52 healthy individuals. The healthy individuals were carefully selected to match the retinoblastoma patients in terms of age, sex, and ethnicity. The data obtained from both groups were subjected to statistical analysis. The study revealed that the methylation level in a cohort of 50 individuals diagnosed with retinoblastoma and 52 healthy control participants was determined to be 36.1% and 33.9%, respectively. As a result, there was no statistically significant disparity observed in RB1 promoter methylation between the patient and control groups (p = 0.126). The methylation of the promoter region of the RB1 gene in familial retinoblastoma does not exert any influence on the hereditary transmission of the disease.

RB1 gene mutations and genetic spectrum in retinoblastoma cases.

The aim of the study was to investigate the frequency and types of mutations on the retinoblastoma gene (RB1 gene) in Turkish population. RB1 gene mutation analysis was performed in a total of 219 individuals (122 probands with retinoblastoma, 14 family members with retinoblastoma and 83 clinically healthy family members). All 27 exons and close intronic regions of the RB1 gene were sequenced for small deletions and insertions using both the Sanger sequencing or NGS methods, and the large deletions and duplications were investigated using the MLPA analysis and CNV algorithm. The bilateral/trilateral retinoblastoma rate was 66% in the study population. The general frequency of RB1 gene mutation in the germline of the patients with retinoblastoma was 41.9%. Approximately 51.5% of the patients were diagnosed earlier than 12 months old, and de novo mutation was found in 32.4% of the patients. Germline small genetic rearrangement mutations were detected in 78.9% of patients and LGRs were detected in 21.1% of patients. An association was detected between the eye color of the RB patients and RB1 mutations. 8 of the mutations detected in the RB1 gene were novel in the study.

Central Nervous System Fungal Infections in Children With Leukemia and Undergoing Hematopoietic Stem Cell Transplantation: A Retrospective Multicenter Study.

BACKGROUND: Central nervous system fungal infections (CNSFI) are seen in patients with hematologic malignancies and have high morbidity and mortality. Because of their rarity, there is limited data on CNSFI in children with no established treatment protocols or guidelines. MATERIALS AND METHODS: In this multicenter retrospective study, 51 pediatric patients with leukemia, 6 of whom had undergone bone marrow transplantation, with proven or probable CNSFI were evaluated. Fungal infections were defined as proven or probable based on European Organisation for Research and Treatment of Cancer criteria. Proven CNSFI was diagnosed by appropriate central nervous system (CNS) imaging or tissue sample findings in combination with positive microbiological results of cerebrospinal fluid. A positive culture, microscopic evidence of hyphae, a positive result of the galactomannan assays are defined as positive microbiological evidence. Probable CNSFI was defined as appropriate CNS imaging findings together with proven or probable invasive fungal infections at another focus without CNS when there is no other explanatory condition. Data was collected by using the questionnaire form (Supplemental Digital Content 1, http://links.lww.com/JPHO/A541 ). RESULTS: Seventeen patients had proven, 34 patients had probable CNSFI. Headaches and seizures were the most common clinical findings. The median time between the onset of fever and diagnosis was 5 days. The most common fungal agent identified was Aspergillus . Sixteen patients received single-agent, 35 received combination antifungal therapy. Surgery was performed in 23 patients. Twenty-two patients (43%) died, 29 of the CNSFI episodes recovered with a 20% neurological sequelae. CONCLUSION: CNSFIs should be considered in the differential diagnosis in patients with leukemia and refractory/recurrent fever, headache, neurologicalocular symptoms, and a radiologic-serological evaluation should be performed immediately. Early diagnosis and prompt management, both medical and surgical, are essential for improving clinical outcomes.

Identification of candidate genes in a family with cancer overload by whole-exome sequencing.

BACKGROUND: Approximately 120 out of every 1 million children in the world develop cancer each year. In Turkey, 2500-3000 children are diagnosed with new cancer each year. The causes of childhood cancer have been studied for many years. It is known that many cancers in children, as in adults, cause uncontrolled cell growth, and develop as a result of mutations in genes that cause cancer. METHODS: The investigation of family history within this context in the study, a total of 13 individuals consisting of all children and adults in the family were examined using the whole-exome sequencing (WES) with the individuals who were diagnosed with cancer in the family, who were detected to have different cancer profiles, and defined as high risk and to determine the gene or genes through which the disease has developed. RESULTS: At the end of the study, a total of 30 variants with a pathogenic record in the family were identified. A total of 10 pathogenic variants belonging to 8 different genes from these variants have been associated with various cancer risks. CONCLUSIONS: A significant scientific contribution has been made to the mechanism of disease formation by studying a family with a high cancer burden and by finding the genes associated with the disease. In addition, by the results obtained, family members with cancer predisposition were selected after a risk analysis conducted in this family, and the necessary examinations and scans were recommended to provide an early diagnostic advantage.

Childhood Rhabdomyosarcoma of the Female Genital Tract: Association with Pathogenic DICER1 Variation, Clinicopathological Features, and Outcomes.

STUDY OBJECTIVE: Rhabdomyosarcomas (RMSs) of the female genital tract (FGT) have been recently shown to be associated with germline pathogenic variation in DICER1, which can underlie a tumor predisposition disorder. We sought to determine the incidence of a pathogenic variation in DICER1 in a cohort of RMSs of the FGT, as well as to evaluate the clinicopathological features and outcomes of the patients. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: We retrospectively reviewed medical records of the patients diagnosed with RMS of the FGT between 1990 and 2019. Molecular genetic sequencing of the tumor to detect an RNase IIIb domain hot spot mutation in DICER1 samples was performed in 7 patients. Individuals with a missense mutation in the tumor were also screened for a loss of function germline mutation in DICER1. RESULTS: Of 210 cases of pediatric RMS, 11 arose from the FGT. Molecular genetic sequencing of the tumor samples revealed a somatic missense mutation in the RNase IIIb domain of DICER1 in a total of 3 patients, 2 patients with embryonal RMS of the cervix/uterus, and 1 patient with ovarian embryonal RMS. As a result of genetic testing for the loss of function germline mutation in DICER1, a heterozygous pathogenic variant was also found in 2 of these patients. CONCLUSION: Despite the limited number of patients, our findings suggest that it is important to be aware of the possible association between RMS of FGT and pathogenic germline DICER1 variants because the detection of this mutation in a patient or relatives can provide the opportunity for surveillance of related conditions that might improve long-term outcomes and survival.

Lymphoma Predisposing Gene in an Extended Family: CD70 Signaling Defect.

Genome-wide sequencing studies in pediatric cancer cohorts indicate that about 10% of patients have germline mutations within cancer predisposition genes. Within this group, primary immune deficiencies take the priority regarding the vulnerability of the patients to infectious agents and the difficulties of cancer management. On the other hand, early recognition of these diseases may offer specific targeted therapies and hematopoietic stem cell transplantation as an option. Besides therapeutic benefits, early diagnosis will provide genetic counseling for the family members. Within this context, an extended family with multiple consanguineous marriages and affected individuals, who presented with combined immune deficiency (CID) and/or Hodgkin lymphoma phenotype, were examined by exome sequencing. A pathogenic homozygous missense CD70 variation was detected (NM_001252.5:c332C>T) in concordance with CD70 phenotype and familial segregation was confirmed. CD70 variations in patients with CID and malignancy have very rarely been reported. This paper reports extended family with multiple affected members with CID and malignancy carrying a missense CD70 variation, and reviews the rare cases reported in the literature. Primary immune deficiencies appear to be a potential cause for pediatric cancers. Better focusing on these inborn disorders to prevent or make an early diagnosis of malignant transformation and reduce mortalities is important.

Children with malignant melanoma: a single center experience from Turkey.

AIM: Malignant melanoma is the most frequent skin cancer in children and adolescents. It comprises 1-3% of all malignancies. In this study, we aimed to evaluate the clinical aspects, histopathologic features, and treatment outcomes of our patients with malignant melanoma. MATERIAL AND METHODS: Patients aged <15 years who were treated between 2003 and 2018 for malignant melanoma were retrospectively analyzed. RESULTS: Seventeen patients (10 females, 7 males), with a median age of 7 years (range, 7 months-13 years) were evaluated. Five patients had congenital melanocytic nevi. All had cutaneous melanoma except one with mucosal (conjunctival) melanoma. The most frequent primary tumor site was the lower extremities (35%). Sentinel lymphoscintigraphy, sentinel node biopsy, and PET/CT were performed as the staging procedures at initial diagnosis. Localized disease was present in eight patients; nine had regional lymph node metastasis. The only treatment was surgery in localized disease; surgery and adjuvant interferon treatment was given in patients with regional lymph node metastasis. Three developed distant metastasis (bone, lung, brain) at a median of 9 months. A three-year-old patient received a BRAF inhibitor (vemurafenib), and a 13-year-old patient received a check point inhibitor (ipilimumab); both died of progressive disease. The median follow-up for all patients was 25 months. The 5-year overall survival was 76.6%. CONCLUSION: Although malignant melanoma is rare in children, prognosis is good if diagnosed early. Physicians should be aware of skin lesions and full-layer biopsy should be obtained in suspicious skin lesions. Patients with congenital melanocytic nevi should also be followed up cautiously.

FGFR4 c.1162G > A (p.Gly388Arg) Polymorphism Analysis in Turkish Patients with Retinoblastoma.

PURPOSE: Various molecular variations are known to result in different gene variants in the FGFR4 gene, known for its oncogenic transformation activity. The goal of this study was to investigate the FGFR4 p.Gly388Arg variant that plays role in the progression of cancer and retinal growth and may be an effective candidate variant in the Turkish population in retinoblastoma patients with no RB1 gene mutation. METHODS: Using the Sanger sequencing methods, the FGFR4 p.Gly388Arg variant was bidirectionally sequenced in 49 patients with non-RB1 gene mutation in retinoblastoma patients and 13 healthy first-degree relatives and 146 individuals matched by sex and age in the control group. RESULTS: In Turkish population-specific study, the FGFR4 p.Gly388Arg variant was found in 27 (55.1 percent) of 49 patients; mutation was found in 7 (53.8 percent) of these patients' 13 healthy relatives screened. When FGFR4 p.Gly388Arg mutation status is evaluated in terms of 146 healthy controls, in 70 (47.9 percent) individuals, mutation was observed. Our analysis showed that the FGFR4 p.Gly388Arg allele frequency, which according to different databases is seen as 30 percent in the general population, is 50 percent common in the Turkish population. CONCLUSIONS: In patients with advanced retinoblastoma who were diagnosed with retinoblastoma prior to 24 months, the FGFR4 p.Gly388Arg allele was found to be significantly higher. As a result, these results indicate that the polymorphism of FGFR4 p.Gly388Arg may play a role in both the development of tumors and the progression of aggressive tumors.

DICER1-Related Embryonal Rhabdomyosarcoma of the Uterine Corpus in a Prepubertal Girl.

BACKGROUND: Germline DICER1 mutations increase the risk of developing a wide variety of generally uncommon tumors. We describe a case of DICER1-related embryonal rhabdomyosarcoma (ERMS) of the uterine corpus in a prepubertal girl. CASE: A 10-year-old- girl with a history of cystic nephroma presented with a 3-week history of vaginal bleeding. A 3-cm mass filling the uterine cavity was detected, and histopathologic examination of hysteroscopy-guided biopsy samples revealed ERMS. Molecular genetic sequencing of the tumor sample revealed a DICER1 mutation. SUMMARY AND CONCLUSION: This report highlights the importance of screening for DICER1 mutations in the presence of the early-onset features of this syndrome, and extends the spectrum of DICER1-related tumors by showing the mutation in a case of ERMS of the uterine corpus.

Investigation of new candidate genes in retinoblastoma using the TruSight One "clinical exome" gene panel.

BACKGROUND: Retinoblastoma (Rb) is the most prevalent intraocular pediatric malignancy of the retina. Significant genetic factors are known to have a role in the development of Rb. METHODS: Here, we report the mutation status of 4813 clinically significant genes in six patients with noncarrier of RB1 gene mutation and having normal RB1 promoter methylation from three families having higher risk for developing Rb in the study. RESULTS: A total of 27 variants were detected in the study. Heterozygous missense variants c.1162G > A (p.Gly388Arg) in the FGFR4 gene; c.559C > T (p.Pro187Ser) in the NQO1 gene were identified. The family based evaluation of the variants showed that the variant, c.714T > G (p.Tyr238Ter), in the CLEC7A gene in first family; the variant, c.55C > T (p.Arg19Ter), in the APOC3 gene and the variant, c.1171C > T (p.Gln391Ter), in the MUTYH gene in second family; and the variant, c.211G > A (p.Gly71Arg), in the UGT1A1 gene in the third family, were found statistically significant (p < 0.05). CONCLUSION: This study might be an important report on emphazing the mutational status of other genes in patients without RB1 gene mutations and having high risk for developing Rb. The study also indicates the interaction between the retinoic acid pathway and Rb oncogenesis for the first time.

Propofol-based balanced anesthesia is safer in pediatric radiotherapy.

BACKROUND AND PURPOSE: To investigate the incidence of complications related to propofol-based anesthesia and the factors associated with complications in children with radiotherapy. MATERIALS AND METHODS: Patients who underwent anesthesia for external beam radiotherapy between May 2013 and November 2017 were included in the study. We assessed the age/weight, sex, oncologic diagnosis, type of radiotherapy procedure, duration of anesthesia, applied agents, and complications related to anesthesia. Complications were evaluated between group I (only propofol group) and group II (propofol plus adjuvant drugs) as respiratory and cardiac. RESULTS: In 130 patients, sedation was given for 1376 radiotherapy procedures. Of these, 1274 (1140 radiation treatment sessions and 134 computed tomography simulations) in 126 patients were propofol-based and were included in the analysis. Although respiratory complications are the most common in both groups, there were no episodes of laryngospasm, broncospasm, and no use of advanced airway intervention. The rate of complication was significantly higher in only propofol anesthesia group than in patients treated with propofol plus adjuvant drugs. In the multivariate analysis, we found three factors that were significantly associated with the risk of complications: total dose of propofol (mg/kg) (p < 0.001), anesthesia with propofol alone (as compared to propofol plus adjunct agents) (p = 0.001), and diagnosis of neuroblastoma (as compared to other diagnosis) (p = 0.043). CONCLUSION: Propofol-based anesthesia is preferred in order to minimize the rate of complications in radiotherapy anesthesia applications. The use of non-opioid adjuvants in combination with propofol to achieve a balanced anesthesia will also reduce the complications that may be encountered.

Vincristine, irinotecan, and temozolomide treatment for refractory/relapsed pediatric solid tumors: A single center experience.

BACKGROUND: Although the survival of pediatric cancer has increased dramatically in the last decades, the survival of refractory, relapsed, and metastatic cases is still dismal. The combination of irinotecan and temozolomide has shown activity against refractory/relapsed pediatric solid tumors. METHOD: Thirty-four children with refractory/relapsed solid tumors who had previously been heavily pretreated and who were given vincristine, irinotecan, and temozolomide as third- or further line chemotherapy during 2004-2015 were evaluated. RESULTS: Patients were diagnosed with Ewing sarcoma (n = 15), rhabdomyosarcoma (n = 8), neuroblastoma (n = 8), osteosarcoma (n = 2), and Wilms' tumor (n = 1). Thirty patients presented with disease progression on therapy and the other four presented with relapsing. A total of 141 cycles were administered. Radiotherapy was used in 17 patients and surgery in 4 as local therapy. Among all patients, 6 had complete response, 3 had partial response, 14 had stable disease, and 11 had progressive disease. The objective response was 26.4% (complete response + partial response) and median survival duration was six months. The first and second year overall survival rates were 22.3% and 16.8%. The objective response in Ewing sarcoma patients was 40%. Diarrhea was the most common toxicity and 14 (10%) courses were associated with grade 3-4 diarrhea. CONCLUSIONS: In heavily pretreated patients with refractory/relapsed solid tumors, the vincristine, irinotecan, and temozolomide regimen seemed promising in Ewing sarcoma patients and was well tolerated.

Nimotuzumab-containing regimen for pediatric diffuse intrinsic pontine gliomas: a retrospective multicenter study and review of the literature.

PURPOSE: Nimotuzumab is an IgG1 antibody that targets epidermal growth factor receptor (EGFR). Overexpression of EGFR is detected in some pediatric brain tumors including diffuse intrinsic pontine gliomas (DIPG)s. METHODS: Since May 2010, nimotuzumab, combined with carboplatin or vinorelbine or Temozolomide (TMZ), was administered during progressive disease (PD) after the use of the institutional protocol consisting of radiotherapy (RT) + TMZ and adjuvant TMZ. After May 2012, children with newly diagnosed disease received TMZ during RT, and nimotuzumab and TMZ after RT. Nimotuzumab was given as 150 mg/m2/dose once a week for 12 weeks, and then every other week with TMZ until PD. PD patients were switched to nimotuzumab + vinorelbine combination until death. RESULTS: Nimotuzumab was used in 24 children with DIPG (seven in the PD group, 17 in the newly diagnosed patient group). In the PD group, median survival time was 12 months (7-42 months); 1-year and 2-year overall survival (OS) rates were 42.9 ± 18% and 14.3 ± 13%, respectively. The median survival in this group, after the initiation of nimotuzumab was 6 months (3-8 months). In the newly diagnosed patient group, median survival time was 11 months (3-35 months) and median progression free survival was 4 months (1-21 months). The 1-year OS in this group was 35.3 ± 11% and 2 year OS was 11.8 ± 7%. Nimotuzumab ± chemotherapy was well tolerated with no major adverse effect. CONCLUSION: Nimotuzumab-containing regimens are feasible and tolerable; it might be that some patients either with newly diagnosed DIPG or with progressive disease may benefit modestly from nimotuzumab-containing combinations.

Cutaneous adverse event associated with vemurafenib in a 3-year-old pediatric patient with BRAF mutation-positive metastatic melanoma and factor X deficiency.

Malignant melanoma is very rare in childhood. The approach to diagnosis and treatment in children has been adopted from adult guidelines. Vemurafenib is indicated in adults with BRAF V600 mutation-positive stage IIIc/IV melanoma and causes cutaneous adverse events. We report on a 3-year-old child with recurrent, metastatic (bone) BRAF mutation-positive melanoma. He also had severe factor X deficiency. Four days after vemurafenib treatment, bilateral palpebral edema and violet-colored hyperpigmentation were observed. There was no objective response to vemurafenib; however, bone pain regressed slightly. Our patient is the youngest patient who received vemurafenib for BRAF V600 mutation-positive metastatic melanoma in the literature.

Primary Rhabdomyosarcoma of the Breast: Imaging Findings and Literature Review.

BACKGROUND: Primary breast rhabdomyosarcoma (RMS) can occur in children. There is a lack of knowledge regarding radiologic findings and added diffusion-weighted magnetic resonance imaging (MRI) features of RMS in the literature. CASE REPORT: A 12-year-old girl was diagnosed with primary alveolar RMS of the breast. Gray scale ultrasound revealed posterior acoustic enhancement behind a well-circumscribed, multilobulated hypoechoic mass. Doppler ultrasound revealed increased peripheral and central vascularity. Hypointense septations on T2-weighted image exhibiting more enhancement than the stroma on late gadolinium-enhanced images were striking within a hyperintense mass. A hyperintense hemorrhagic focus on T1-weighted image was present in the absence of any necrosis. Avid enhancement on early postcontrast images proceeding from the periphery to the center was depicted. CONCLUSION: A rapidly enlarging mass with an echogenic peripheral rim together with posterior acoustic enhancement on gray scale ultrasound, intense vascularity on Doppler ultrasound, axillary lymphadenopathy, and satellite nodules on MRI should raise suspicion. Enhancing central and peripheral septations are suggestive of RMS. Dynamic contrast-enhanced MRI in suspected cases can provide valuable data in the differential diagnosis.

Osteosarcoma of the rib: A rare presentation.

In children and adolescents with chest pain and dyspnea, pneumonia, pleural effusion, and empyema are the frequent causes in the differential diagnosis. Malignant tumors of the chest wall are rare and most originate from the ribs. In children, the most frequent malignant tumor of the rib is Ewing's sarcoma. Osteosarcomas of the rib are very rare. Osteosarcoma has a predilection for rapidly growing long bones including the femur, tibia and humerus in adolescents. In this paper, we present an adolescent girl who presented with chest pain and dyspnea with osteosarcoma that originated from the rib and extended to the right hemithorax.

Simultaneous Presentation of Wilms' Tumor and Contralateral Ganglioneuroma in a Child: Case Report and Literature Review.

We demonstrate a 4-year-old girl who presented with progressive, asymmetrical, firm abdominal distention and was diagnosed with synchronous Wilms' tumor and left para-aortic ganglioneuroma (GN). Although synchronous tumors in the pediatric population are commonly associated with malignancy-predisposing syndromes, the patient in question was found to be otherwise healthy and had no clinical evidence nor family history of a syndrome. This case is the second one in the literature diagnosed with synchronous presentation of Wilms' tumor and GN in a previously healthy child. In addition, a GN foci presumed to be a previous metastasis of a neurogenic tumor that subsequently matured to GN was depicted within a left para-aortic lymph node. We aimed to emphasize an extremely rare synchronous occurrence of these embryonal tumors, increase the awareness of physicians, and discuss the radiologic differential diagnosis and management.

Respiratory viral infection`s frequency and clinical outcome in symptomatic children with cancer: A single center experience from a middle-income country.

Büyükkapu-Bay S, Kebudi R, Görgün Ö, Mese S, Zülfikar B, Badur S. Respiratory viral infection`s frequency and clinical outcome in symptomatic children with cancer: A single center experience from a middle-income country. Turk J Pediatr 2018; 60: 653-659. In developing countries, acute respiratory tract infections are a significant cause of morbidity and mortality in children, particularly in pediatric cancer patients. A majority of these illnesses are precipitated by viral infections. In our country, studies were conducted on the single respiratory viral infection in a pediatric hematology-oncology unit; however, the analysis of respiratory viral infections in children with cancer is lacking. The present study aimed to provide analysis of multiple respiratory viral infections and clinical outcome in children with cancer who receive chemotherapy and show signs and symptoms of respiratory tract infections. During January, 2014 and January, 2015 children with cancer under treatment who presented with respiratory tract infections were assessed for viruses by using multiplex real-time reverse transcription polymerase chain reaction (rRT-PCR). Specimens were collected by nasal swabbing at in-patient and out-patient clinics. Overall, 72 samples of respiratory tract infection episodes, collected from children with cancer were evaluated with the simultaneous detection of 20 respiratory viruses. A respiratory viral pathogen was obtained in 56.9% samples. Rhinovirus (24.3%) and co-infection with two viruses (19.5%) were the most frequently isolated pathogens. There were four (9.6%) samples of severe pneumonia. Patients with febrile neutropenic episodes and pneumonia were hospitalized and treated with broad-spectrum antibiotics. Other non-neutropenic and mild respiratory tract infections were treated with supportive care as outpatient procedures. There were no deaths. Because there are no effective antiviral agents for certain respiratory viruses, infection control and early diagnosis are crucial in preventing the spread of infection. Clinical findings and serological results of viral respiratory tract infections help us to accurately determine the treatment approach and avoid the unnecessary use of antibiotics.