Panel‑based next‑generation sequencing facilitates the characterization of childhood acute myeloid leukemia in clinical settings

Acute myeloid leukemia (AML) accounts for ~20% of pediatric leukemia cases. The prognosis of pediatric AML has been improved in recent decades, but it trails that of most other types of pediatric cancer, with mortality rates of 30‑40%. Consequently, newer more targeted drugs are required for incorporation into treatment plans. These newer drugs selectively target AML cells with specific gene alterations. However, there are significant differences in genetic alterations between adult and pediatric patients with AML. In the present study, inexpensive and rapid next‑generation sequencing (NGS) of >150 cancer‑related genes was performed for matched diagnostic, remission and relapse (if any) samples from 27 pediatric patients with AML. In this analysis, seven genes were recurrently mutated. KRAS was mutated in seven patients, NRAS was mutated in three patients, and KIT, GATA1, WT1, PTPN11, JAK3 and FLT3 were each mutated in two patients. Among patients with relapsed AML, six harbored KRAS mutations at diagnosis; however, four of these patients lost these mutations at relapse. Additionally, two genetic alterations (FLT3‑ITD and TP53 alterations) were detected among patients who eventually relapsed, and these mutations are reported to be adverse prognostic factors for adult patients with AML. This panel‑based, targeted sequencing approach may be useful in determining the genetic background of pediatric AML and improving the prediction of treatment response and detection of potentially targetable gene alterations. RAS pathway mutations were highly unstable at relapse; therefore, these mutations should be chosen as a target with caution. Incorporating this panel‑based NGS approach into the clinical setting may allow for a patient‑oriented strategy of precision treatment for childhood AML

Survey of understanding and awareness of fertility preservation in pediatric patients: Is conversation about fertility preservation unpleasant for pediatric patients?

ObjectiveTo verify understanding and awareness of fertility preservation (FP) in pediatric patients undergoing FP treatments.MethodsA questionnaire survey was conducted before and after explanation of fertility issues and FP treatments for patients 6–17 years old who visited or were hospitalized for the purpose of ovarian tissue cryopreservation (OTC) or oocyte cryopreservation (OC), or sperm cryopreservation between October 2018 and April 2022. This study was approved by the institutional review board at St. Marianna University School of Medicine (No. 4123, UMIN000046125).ResultParticipants in the study comprised 36 children (34 girls, 2 boys). Overall mean age was 13.3 ± 3.0 years. The underlying diseases were diverse, with leukemia in 14 patients (38.9%), brain tumor in 4 patients (11.1%). The questionnaire survey before the explanation showed that 19 patients (52.8%) wanted to have children in the future, but 15 (41.7%) were unsure of future wishes to raise children. And most children expressed some degree of understanding of the treatment being planned for the underlying disease (34, 94.4%). Similarly, most children understood that the treatment would affect their fertility (33, 91.7%). When asked if they would like to hear a story about how to become a mother or father after FP which including information of FP, half answered “Don’t mind” (18, 50.0%). After being provided with information about FP treatment, all participants answered that they understood the adverse effects on fertility of treatments for the underlying disease. Regarding FP treatment, 32 children (88.9%) expressed understanding for FP and 26 (72.2%) wished to receive FP. “Fear” and “Pain” and “Costs” were frequently cited as concerns about FP. Following explanations, 33 children (91.7%) answered “Happy I heard the story” and no children answered, “Wish I hadn’t heard the story”. Finally, 28 of the 34 girls (82.4%) underwent OTC and one girl underwent OC.DiscussionThe fact that all patients responded positively to the explanations of FP treatment is very informative. This is considered largely attributable to the patients themselves being involved in the decision-making process for FP.ConclusionsExplanations of FP for children appear valid if age-appropriate explanations are provided

Less than 5 Netrin-1 molecules initiate attraction but 200 Sema3A molecules are necessary for repulsion

Guidance molecules, such as Sema3A or Netrin-1, induce growth cone (GC) repulsion or attraction. In order to determine the speed of action and efficiency of these guidance cues we developed an experimental procedure to deliver controlled amounts of these molecules. Lipid vesicles encapsulating 10-10 4 molecules of Sema3A or Netrin-1 were manipulated with high spatial and temporal resolution by optical tweezers and their photolysis triggered by laser pulses. Guidance molecules released from the vesicles diffused and reached the GC membrane in a few seconds. Following their arrival, GCs retracted or grew in 20-120 s. By determining the number of guidance molecules trapped inside vesicles and estimating the fraction of guidance molecules reaching the GC, we show that the arrival of less than 5 Netrin-1 molecules on the GC membrane is sufficient to induce growth. In contrast, the arrival of about 200 Sema3A molecules is necessary to induce filopodia repulsion

Neogenin May Functionally Substitute for Dcc in Chicken

Dcc is the key receptor that mediates attractive responses of axonal growth cones to netrins, a family of axon guidance cues used throughout evolution. However, a Dcc homolog has not yet been identified in the chicken genome, raising the possibility that Dcc is not present in avians. Here we show that the closely related family member neogenin may functionally substitute for Dcc in the developing chicken spinal cord. The expression pattern of chicken neogenin in the developing spinal cord is a composite of the distribution patterns of both rodent Dcc and neogenin. Moreover, whereas the loss of mouse neogenin has no effect on the trajectory of commissural axons, removing chicken neogenin by RNA interference results in a phenotype similar to the functional inactivation of Dcc in mouse. Taken together, these data suggest that the chick neogenin is functionally equivalent to rodent Dcc

Prominence of NUDT15 genetic variation associated with 6-mercaptopurine tolerance in a genome-wide association study of Japanese children with acute lymphoblastic leukaemia

Inherited genetic variation is associated with 6-mercaptopurine (6-MP) dose reduction and frequent toxicities induced by 6-MP. However, the tolerable dose for 6-MP is not fully predicted by the known variation in NUDT15 and TPMT among Asian children with acute lymphoblastic leukaemia (ALL). We performed a genome-wide association study (GWAS) related to 6-MP dose among Japanese children with ALL. This GWAS comprised 224 patients previously enrolled in Tokyo Children's Cancer Study Group clinical studies with replication attempted in 55 patients. Genome-wide single nucleotide polymorphism (SNP) genotypes were evaluated for association with average 6-MP dose during the initial 168 days of maintenance therapy. Possible associations were observed across five gene-coding regions, among which only variants at 13q14.2 were significant and replicated genome-wide (rs116855232, NUDT15, beta = -10.99, p = 3.7 x 10(-13)). Notable findings were observed for variants in AFF3 (rs75364948, p = 2.05 x 10(-6)) and CHST11 (rs1148407, p = 2.09 x 10(-6)), but were not replicated possibly due to small numbers. A previously reported candidate SNP in MTHFR was associated with higher average 6-MP dose (rs1801133, p = 0.045), and FOLH1 (rs12574928) was associated in an evaluation of candidate regions (p(adjust) = 0.013). This study provides strong evidence that rs116855232 in NUDT15 is the genetic factor predominantly associated with 6-MP tolerable dose in children in Japan

Regional evaluation of childhood acute lymphoblastic leukemia genetic susceptibility loci among Japanese

Genome-wide association studies (GWAS) performed mostly in populations of European and Hispanic ancestry have confirmed an inherited genetic basis for childhood acute lymphoblastic leukemia (ALL), but these associations are less clear in other races/ethnicities. DNA samples from ALL patients (aged 0–19 years) previously enrolled onto a Tokyo Children’s Cancer Study Group trial were collected during 2013–2015, and underwent single nucleotide polymorphism (SNP) microarray genotyping resulting in 527 B-cell ALL for analysis. Cases and control data for 3, 882 samples from the Nagahama Study Group and Aichi Cancer Center Study were combined, and association analyses across 10 previous GWAS-identified regions were performed after targeted SNP imputation. Linkage disequilibrium (LD) patterns in Japanese and other populations were evaluated using the varLD score based on 1000 Genomes data. Risk associations for ARID5B (rs10821936, OR = 1.84, P = 6 × 10⁻¹⁷) and PIP4K2A (rs7088318, OR = 0.76, P = 2 × 10⁻⁴) directly transferred to Japanese, and the IKZF1 association was detected by an alternate SNP (rs1451367, OR = 1.52, P = 2 × 10⁻⁶). Marked regional LD differences between Japanese and Europeans was observed for most of the remaining loci for which associations did not transfer, including CEBPE, CDKN2A, CDKN2B, and ELK3. This study represents a first step towards characterizing the role of genetic susceptibility in childhood ALL risk in Japanese