Promoter swapping of truncated PDGFRB drives Ph-like acute lymphoblastic leukemia.

Philadelphia chromosome (Ph)-like acute lymphoblastic leukemia (ALL) is a subset of ALL that demonstrated a high treatment failure rate. One of the hallmarks of Ph-like ALL is PDGFRB gene fusion, with fusion partner proteins often harboring dimerization domains and enhancing the kinase activity of PDGFRB. We determined a novel oncogenic PDGFRB fusion gene, NRIP1::PDGFRB, from a pediatric patient with ALL, encoding a protein with the carboxy-terminal kinase domain of PDGFRB, without the partner peptide. We confirmed the oncogenic potential of NRIP1::PDGFRB in vitro and the efficacy of all ABL1-specific inhibitor generations, including imatinib, dasatinib, nilotinib, and ponatinib, in suppressing this potential. PDGFRB activation mechanism may include juxtamembrane domain truncation in the predicted peptide. In conclusion, we determined a novel fusion gene pattern in Ph-like ALL.

Pediatric Precision Medicine at the National Cancer Center Japan: Prospective Genomic Study of Pediatric Patients with Cancer as Part of the TOP-GEAR Project.

PURPOSE: This single-center, prospective molecular profiling study characterizes genomic alterations and identifies therapeutic targets in advanced pediatric solid tumors. METHODS: As part of the TOP-GEAR (Trial of Onco-Panel for Gene profiling to Estimate both Adverse events and Response by cancer treatment) project at the National Cancer Center (NCC), Japan, we enrolled pediatric patients with a refractory or recurrent disease during August 2016-December 2021 and performed genomic analysis of matched tumors and blood using originally developed cancer gene panels, NCC Oncopanel (ver. 4.0) and NCC Oncopanel Ped (ver. 1.0). RESULTS: Of 142 patients (age, 1-28 years) enrolled, 128 (90%) were evaluable for genomic analysis; 76 (59%) patients harbored at least one reportable somatic or germline alteration. The tumor samples were collected during the initial diagnosis in 65 (51%) patients, after treatment initiation in 11 (9%) patients, and upon either disease progression or relapse in 52 (41%) patients. The leading altered gene was TP53, followed by MYCN, MYC, CDKN2A, and CDK4. The commonly affected molecular processes were transcription, cell-cycle regulation, epigenetic modifiers, and RAS/mitogen-activated protein kinase signaling. Twelve (9%) patients carried pathogenic germline variants in cancer-predisposing genes. Potentially actionable findings were identified in 40 (31%) patients; to date, 13 (10%) patients have received the recommended therapy on the basis of their genomic profiles. Although four patients had access to targeted therapy through clinical trials, the agents were used in nine patients in an off-label setting. CONCLUSION: The implementation of genomic medicine has furthered our understanding of tumor biology and provided new therapeutic strategies. However, the paucity of proposed agents limits the full potential of actionability, emphasizing the significance of facilitating access to targeted cancer therapies.

Safety and efficacy of multiple tyrosine kinase inhibitors in pediatric/adolescent and young adult patients with relapsed or refractory osteosarcomas: A single-institution retrospective analysis.

BACKGROUND: The prognosis of relapsed or refractory osteosarcoma remains poor. Recent reports have stated that molecular targeting agents, including multiple tyrosine kinase inhibitors (MTKIs), are effective against adult osteosarcoma. To determine the safety and efficacy of MTKI therapy in children, adolescents and young adults (AYAs), we conducted a retrospective study on adverse events and treatment outcomes. METHODS: We retrospectively reviewed the medical records of patients with relapsed or refractory osteosarcoma who received MTKI therapy at the Department of Pediatric Oncology, National Cancer Center Hospital, from December 2013 to May 2021. RESULTS: The study included 31 patients (15 males and 16 females) who received MTKIs, including sorafenib monotherapy (seven patients), sorafenib and everolimus (14 patients), and regorafenib monotherapy (10 patients). Their median age was 17 years (range: 11-22 years). The incidence of treatment-related grade 3 nonhematological adverse events was 14.3% in the sorafenib monotherapy group, 21.4% in the sorafenib with everolimus group, and 20.0% in the regorafenib monotherapy group. No grade 4 nonhematological adverse events were observed. The median progression-free survival (PFS) was 51 days in the sorafenib monotherapy group, 101 days in the sorafenib with everolimus group, and 167 days in the regorafenib monotherapy group. CONCLUSION: The safety profile of MTKI therapies in pediatric and AYA patients was comparable to that in adult patients. MTKI therapies, particularly regorafenib, against pediatric relapsed osteosarcoma can suppress tumor growth and prolong PFS with tolerable adverse events.

[Gemcitabine and Docetaxel for the Treatment of Relapsed and Refractory Malignant Rhabdoid Tumor of Kidney and Atypical Teratoid Rhabdoid Tumor].

Gemcitabine and Docetaxel(GEM/DTX)are well known chemotherapeutic drugs for the treatment of soft tissue sarcomas. However, the efficacy of these drugs in the treatment of malignant rhabdoid tumors(MRTs)has not been well described. We used GEM/DTX as salvage chemotherapy for relapsed and refractory MRTs, including 2 patients with malignant rhabdoid tumor of the kidney(MRTK)and 2 with atypical teratoid rhabdoid tumor(ATRT). At the best, partial response was observed in 3 patients(2 MRTK and 1 ATRT). The remaining patient with ATRT had stable disease. Localized edema in the field of recent radiation therapy was discovered in 2 patients. In addition, one had pleural effusion without any evidence of tumor progression. GEM/DTX can be used as a potential chemotherapeutic drug for relapsed or refractory MRTs, although attention should be paid to its unique adverse events.

Monitoring Ponatinib in a Child with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia.

Ponatinib is a third-generation tyrosine kinase inhibitor (TKI) reported to show a higher efficacy for adult Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) than other TKIs. However, few studies describe ponatinib for pediatric Ph+ALL; therefore, the efficacy, safety, and optimal dosage have not been determined. Here, we report a 3-year-old girl with Ph+ALL treated by a ponatinib-containing regimen with therapeutic drug monitoring in the plasma and cerebrospinal fluid (CSF). In our case, a ponatinib-containing regimen was able to keep minimal residual disease negative, and the pharmacokinetics (PKs) of plasma ponatinib resembled that previously reported in adults. Penetration to the CSF was extremely limited. Thus, ponatinib was feasible and effective for a child with Ph+ALL, although the plasma concentration of ponatinib varied significantly throughout the treatment. The appropriate dosage should be confirmed in a prospective trial, including a detailed PK study.

[Anesthetic Management Using Transesophageal Echocardiography and EV1000 in a Patient with Ebstein's Anomary Undergoing Scoliosis Surgery].

An 18-year-old female patinet with Ebstein anomaly underwent surgical repair of scoliosis under total intravenous anesthesia. In addtition to normal monitors, we used transesophageal echocardiography (TEE) and EV1000 (Edwards Lifesciences, Irvine, USA), which show stroke volume variation and stroke volume index simultaneously in a rectangular coordinates. TEE detected reversal of intracardiac shunt which caused SpO2 decrease during fixing screws at thoracic vertebrae, then manual ventilation with oxygen unproved SpO2. Because of a high venous pressure due to Ebstein anomaly, surgical bleeding seemed to be larger than usual. By using EV1000, volume status and cardiac contractility were estimated and adequate volume loading and inoptrope injection were performed to stabilize circulatory condition. The operation was completed without any cardiac and respiratory complications.