High-dose carboplatin-irinotecan-temozolomide is an effective salvage chemotherapy for relapsed or refractory neuroblastoma.

There is no clear consensus on the most effective treatment for relapsed/refractory high-risk neuroblastoma (NB). We retrospectively assessed seven NB patients with relapsed/refractory disease who received high-dose carboplatin-irinotecan-temozolomide (HD-CIT). Five of seven patients showed favorable therapeutic response (complete remission or partial remission). Regarding toxicity, the cytopenia period tended to prolong when more than three cycles were repeated, but nonhematological toxicities were controllable with general supportive care. Due to its antitumor efficacy and well-tolerated nonhematologic toxicity, HD-CIT is a promising salvage chemotherapy for relapsed/refractory NB. However, it is important to pay attention to the exacerbation of hematological toxicity when repeating the regimen.

Use of Cabozantinib to Treat MET -amplified Pediatric Colorectal Cancer.

Pediatric colorectal cancer (CRC) is extremely rare, with little information about genetic profiles compared with adult CRC. Here, a 13-year-old male with advanced CRC underwent cancer gene panel testing, which detected 4 genetic abnormalities ( MET amplification in addition to TP53 , SMAD4 , and CTNNA1 mutations) that might be associated with a poor prognosis. Based on high-level MET amplification, he received a multikinase inhibitor, cabozantinib, after failure of first-line and second-line chemotherapy, resulting in transient disease stabilization. Tailored targeted therapy based on molecular profiling can be an effective treatment strategy for rare cancers such as pediatric CRC.

Fulminant Type 1 Diabetes Mellitus Caused by Long-Term Nivolumab Administration Followed by Nivolumab plus Cabozantinib Combination.

Nivolumab, an immune checkpoint inhibitor (ICI), is now used to treat many advanced cancers, including non-small cell lung cancer (NSCLC) and renal cancer. Immune-related adverse events are characteristic side effects of ICIs. Among them, fulminant type 1 diabetes mellitus is an infrequent but potentially life-threatening and clinically significant concern. Cabozantinib is known as a multikinase inhibitor. In recent years, combination therapy with nivolumab and cabozantinib has begun to be used to treat renal cell carcinoma. A 74-year-old man with no history of diabetes was treated with nivolumab for 5 years for NSCLC, followed by the combination of nivolumab and cabozantinib for clear cell renal cell carcinoma. He was diagnosed with fulminant type 1 diabetes 5 weeks after starting combination therapy, with symptoms of nausea and dry mouth. He was admitted to the intensive care unit and improved clinically with continuous insulin infusion and saline. The involvement of cabozantinib in the development of fulminant type 1 diabetes with long-term nivolumab use, which has not been reported previously, is unknown, but caution may be necessary in terms of glycemic control in combination therapy with nivolumab and cabozantinib.

PAX5 alterations in an infant case of KMT2A-rearranged leukemia with lineage switch.

Lineage switch is a rare event at leukemic relapse. While mostly known to occur in KMT2A-rearranged infant leukemia, the underlying mechanism is yet to be depicted. This case report describes a female infant who achieved remission of KMT2A-MLLT3-rearranged acute monocytic leukemia, but 6 months thereafter, relapsed as KMT2A-MLLT3-rearranged acute lymphocytic leukemia. Whole exome sequencing of the bone marrow obtained pre-post lineage switch revealed two somatic mutations of PAX5 in the relapse sample. These two PAX5 alterations were suggested to be loss of function, thus to have played the driver role in the lineage switch from acute monocytic leukemia to acute lymphocytic leukemia.

The first Japanese biobank of patient-derived pediatric acute lymphoblastic leukemia xenograft models.

A lack of practical resources in Japan has limited preclinical discovery and testing of therapies for pediatric relapsed and refractory acute lymphoblastic leukemia (ALL), which has poor outcomes. Here, we established 57 patient-derived xenografts (PDXs) in NOD.Cg-Prkdcscid ll2rgtm1Sug /ShiJic (NOG) mice and created a biobank by preserving PDX cells including three extramedullary relapsed ALL PDXs. We demonstrated that our PDX mice and PDX cells mimicked the biological features of relapsed ALL and that PDX models reproduced treatment-mediated clonal selection. Our PDX biobank is a useful scientific resource for capturing drug sensitivity features of pediatric patients with ALL, providing an essential tool for the development of targeted therapies.

Alteration of the immune environment in bone marrow from children with recurrent B cell precursor acute lymphoblastic leukemia.

Due to the considerable success of cancer immunotherapy for leukemia, the tumor immune environment has become a focus of intense research; however, there are few reports on the dynamics of the tumor immune environment in leukemia. Here, we analyzed the tumor immune environment in pediatric B cell precursor acute lymphoblastic leukemia by analyzing serial bone marrow samples from nine patients with primary and recurrent disease by mass cytometry using 39 immunophenotype markers, and transcriptome analysis. High-dimensional single-cell mass cytometry analysis elucidated a dynamic shift of T cells from naïve to effector subsets, and clarified that, during relapse, the tumor immune environment comprised a T helper 1-polarized immune profile, together with an increased number of effector regulatory T cells. These results were confirmed in a validation cohort using conventional flow cytometry. Furthermore, RNA transcriptome analysis identified the upregulation of immune-related pathways in B cell precursor acute lymphoblastic leukemia cells during relapse, suggesting interaction with the surrounding environment. In conclusion, a tumor immune environment characterized by a T helper 1-polarized immune profile, with an increased number of effector regulatory T cells, could contribute to the pathophysiology of recurrent B cell precursor acute lymphoblastic leukemia. This information could contribute to the development of effective immunotherapeutic approaches against B cell precursor acute lymphoblastic leukemia relapse.

RUNX1 transactivates BCR-ABL1 expression in Philadelphia chromosome positive acute lymphoblastic leukemia.

The emergence of tyrosine kinase inhibitors as part of a front-line treatment has greatly improved the clinical outcome of the patients with Ph+ acute lymphoblastic leukemia (ALL). However, a portion of them still become refractory to the therapy mainly through acquiring mutations in the BCR-ABL1 gene, necessitating a novel strategy to treat tyrosine kinase inhibitor (TKI)-resistant Ph+ ALL cases. In this report, we show evidence that RUNX1 transcription factor stringently controls the expression of BCR-ABL1, which can strategically be targeted by our novel RUNX inhibitor, Chb-M'. Through a series of in vitro experiments, we identified that RUNX1 binds to the promoter of BCR and directly transactivates BCR-ABL1 expression in Ph+ ALL cell lines. These cells showed significantly reduced expression of BCR-ABL1 with suppressed proliferation upon RUNX1 knockdown. Moreover, treatment with Chb-M' consistently downregulated the expression of BCR-ABL1 in these cells and this drug was highly effective even in an imatinib-resistant Ph+ ALL cell line. In good agreement with these findings, forced expression of BCR-ABL1 in these cells conferred relative resistance to Chb-M'. In addition, in vivo experiments with the Ph+ ALL patient-derived xenograft cells showed similar results. In summary, targeting RUNX1 therapeutically in Ph+ ALL cells may lead to overcoming TKI resistance through the transcriptional regulation of BCR-ABL1. Chb-M' could be a novel drug for patients with TKI-resistant refractory Ph+ ALL.

CN470 is a BET/CBP/p300 multi-bromodomain inhibitor and has an anti-tumor activity against MLL-rearranged acute lymphoblastic leukemia.

Acute lymphoblastic leukemia with chromosomal rearrangements involving the mixed-lineage leukemia (MLL) gene (MLL-r ALL) remains an incurable disease. Thus, development of a safe and effective therapeutic agent to treat this disease is crucial to address this unmet medical need. BRD4, a member of the bromodomain and extra-terminal domain (BET) protein family, and cyclic AMP response element binding protein binding protein (CBP) and p300, two paralogous histone acetyltransferases, are all considered cancer drug targets and simultaneous targeting of these proteins may have therapeutic advantages. Here, we demonstrate that a BET/CBP/p300 multi-bromodomain inhibitor, CN470, has anti-tumor activity against MLL-r ALL in vitro and in vivo. CN470, potently inhibited ligand binding to the bromodomains of BRD4, CBP, and p300 and suppressed the growth of MLL-r ALL cell lines and patient-derived cells with MLL rearrangements. CN470 suppressed mRNA and protein expression of MYC and induced apoptosis in MLL-r ALL cells, following a cell cycle arrest in the G1 phase. Moreover, CN470 reduced BRD4 binding to acetylated histone H3. The in vivo effects of CN470 were investigated using SEMLuc/GFP cells expressing luminescent markers in an orthotopic mouse model. Mice administered CN470 daily had prolonged survival compared to the vehicle group. Further, CN470 also showed anti-tumor effects against an MLL-r ALL patient-derived xenograft model. These findings suggest that inhibition of BET/CBP/p300 by the multi-bromodomain inhibitor, CN470, represents a promising therapeutic approach against MLL-r ALL.

Low-Level Germline 48,XYY,+21 Mosaicism Associated with Transient Abnormal Myelopoiesis in a Phenotypically Normal Neonate.

Transient abnormal myelopoiesis (TAM) is a unique neonatal leukemoid reaction caused by a pathognomonic GATA1 mutation in conjunction with the gene dosage effect of trisomy 21, which is either of germline or somatic origin. We encountered a 48,XYY,+21 phenotypically normal neonate with Down syndrome who developed TAM due to cryptic germline mosaicism. Quantification of the mosaic ratio was complicated by an overestimation bias of hyperproliferating TAM within the germline component. To establish a workflow for such a clinical scenario, we analyzed the cytogenetic findings of neonates with TAM associated with somatic or low-level germline mosaicism. We showed that multistep diagnostic procedures (i.e., paired cytogenetic analyses of peripheral blood specimens in culture with or without phytohemagglutinin; serial cytogenetic studies of more than one tissue, such as the buccal membrane; and complementary DNA-based GATA1 mutation screening) can verify the specificity of cytogenetic testing for phenotypically normal neonates with TAM suspected of mosaicism.

Improvement of Bone Marrow Necrosis by Tyrosine Kinase Inhibitor Substitution in a Pediatric Patient With Philadelphia Chromosome-positive Acute Lymphoblastic Leukemia.

Bone marrow necrosis (BMN) describes necrosis of the myeloid tissues without cortical bone involvement. Imatinib, a tyrosine kinase inhibitor, can trigger BMN during the treatment of malignant disease. In such cases, it is necessary to reduce imatinib dose or discontinue its administration, which could influence treatment outcomes. Here, we report a 6-year-old boy with Philadelphia chromosome-positive acute lymphoblastic leukemia, who developed BMN in response to imatinib. We replaced imatinib with dasatinib, and necrotic lesions gradually disappeared and were never exacerbated. In Philadelphia chromosome-positive acute lymphoblastic leukemia with BMN, tyrosine kinase inhibitor replacement may allow continued chemotherapy without intensity reduction.

High-dose chemotherapy with autologous stem cell transplantation spares re-irradiation for recurrent intracranial germinoma.

The clinical outcome of high-dose chemotherapy (HDC) with autologous stem cell transplantation was retrospectively analyzed in six patients with recurrent intracranial germinoma. Prior to HDC, all patients achieved complete remission after platinum and ifosfamide-based chemotherapy. A melphalan-based conditioning regimen was administered in either a single cycle or multiple sequential cycles. Five of the six patients are alive and free from disease, with a median survival of 65 months, among which four patients avoided re-irradiation. In a significant proportion of patients, recurrent intracranial germinoma is curable by HDC without re-irradiation, provided that the disease remains sensitive to salvage chemotherapy.

Somatic mosaicism for a NRAS mutation associates with disparate clinical features in RAS-associated leukoproliferative disease: a report of two cases.

RAS-associated leukoproliferative disease (RALD) is a newly classified disease; thus its clinical features and management are not fully understood. The cases of two patients with characteristic features of RALD are described herein. Patient 1 was a 5-month-old female with clinical features typical of autoimmune lymphoproliferative syndrome (ALPS) and markedly elevated TCRαß(+)CD4(-)CD8(-) T cell numbers. Genetic analyses failed to detect an ALPS-related gene mutation; however, whole exome sequencing and other genetic analyses revealed somatic mosaicism for the G13D NRAS mutation. These data were indivative of NRAS-associated RALD with highly elevated αß-double-negative T cells. Patient 2 was a 12-month-old girl with recurrent fever who clearly met the diagnostic criteria for juvenile myelomonocytic leukemia (JMML). Genetic analyses revealed somatic mosaicism, again for the G13D NRAS mutation, suggesting RALD associated with somatic NRAS mosaicism. Notably, unlike most JMML cases, Patient 2 did not require steroids or hematopoietic stem cell transplantation. Genetic analysis of RAS should be performed in patients fulfilling the diagnostic criteria for ALPS in the absence of ALPS-related gene mutations if the patients have elevated αß-double-negative-T cells and in JMML patients if autoimmunity is detected. These clinical and experimental data increase our understanding of RALD, ALPS, and JMML.

Identification of the narrow lumen of the ureter using a Fogarty catheter during laparoscopic pyeloplasty.

It is difficult to identify the narrow sites of the ureter from the outside while carrying out laparoscopic pyeloplasty in patients with ureteropelvic junction obstruction. We developed and named a new method, the Fogarty test, to identify the narrow sites of the ureter using a Fogarty catheter. A 4- to 5-Fr Fogarty catheter was inserted through an incision in the pelvis to the proximal ureter, inflated with air and withdrawn gently to determine resistance. The narrow lumen of the ureter was identified under direct vision and spatulated by laparoscopic scissors. This procedure was carried out repeatedly until the ureter was fully spatulated. By using the Fogarty test, we can visualize the narrow position and length of the ureter under direct vision, and confirm whether it is fully spatulated or not. This technique is very simple and easy to carry out. We believe it is useful for sufficient spatulation of intrinsic ureteral stricture, especially in patients where multiple narrow sites exist.

[Case of cystitis glandularis causing bilateral hydronephrosis].

A 38 year-old male was referred to our hospital due to bilateral hydronephrosis. Cystoscopy revealed multiple edematous papillary tumors that exist on the prostatic urethra, bladder neck, trigone, and lateral wall on both sides. He underwent a transurethral resection of bladder tumors. The pathological diagnosis was cystitis glandularis. He was given steroid orally for 6 months and had no sign of recurrence after 2 years.

Two Cases of Exacerbation of Asthma during Treatment with Enfortumab Vedotin.

Enfortumab vedotin is an antibody-drug conjugate against nectin-4 that is recently being used in the management of patients with urothelial carcinoma. The common adverse events include rashes, peripheral neuropathy, and hyperglycemia. Only a few cases of associated respiratory symptoms have been reported. Herein, we describe 2 patients with advanced urothelial carcinoma who experienced asthma exacerbation after initiating enfortumab vedotin treatment. Both patients improved with inhalation therapy. Since nectin-4 is expressed in the tracheal epithelium, its association with asthma is likely. This study highlights that clinicians should caution patients with a history of asthma against the worsening of respiratory symptoms when enfortumab vedotin is administered.