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Background: Drug resistance remains a significant impediment in leukemia treatment. While Bendamustine hydrochloride (BH) stands out as a promising therapeutic agent for non-Hodgkin's lymphoma and mantle cell lymphoma, the mechanisms of resistance to BH are not yet fully understood. Our study focuses on elucidating the mechanisms behind bendamustine resistance in leukemia cells, with a specific emphasis on epigenetics., Methods: Bendamustine-resistant cells were cultivated from human B cell lymphoblastic leukemia cell lines through systematic and sustained exposure to bendamustine, using the limiting dilution method. Gene expression was assessed via real-time polymerase chain reaction, while the expression of the multidrug resistance protein 1 (MDR1) was evaluated using flow cytometry., Results: Bendamustine-resistant leukemia cells exhibited a decreased RNA expression level for Polo-like kinase-1 (PLK-1). Notably, after treatment with the demethylating agent 5-aza-2'-deoxycytidine, PLK-1 gene expression surged significantly, enhancing bendamustine's cytotoxicity in the resistant leukemia cells. However, MDR1 expression, as determined by flow cytometry, remained consistent between parental and bendamustine-resistant leukemia cells., Conclusions: Our findings indicate that the methylation of the PLK-1 gene plays a pivotal role in modulating PLK-1 expression and is central to the development of bendamustine resistance in leukemia cells.

Background: Adipose tissue-derived mesenchymal stem cells (ADSCs) are used for the treatment of various diseases because of their rapid proliferation and high anti-inflammatory and tissue repair properties. Kawasaki disease is a systemic vasculitis with coronary arteritis and aneurysms occurring in pediatric patients. In this study, we examined serologically and pathologically whether the administration of human ADSCs (hADSCs) to a mouse model of Kawasaki disease could suppress vasculitis., Methods: Candida albicans water-soluble fractions were intraperitoneally injected into DBA/2 mice for 5 consecutive days to generate a mouse model of Kawasaki disease. The model mice were intravenously administered hADSCs or phosphate-buffered saline (PBS). Serum samples collected on days 15 and 29 were used to compare cytokine levels. Mouse hearts dissected on day 29 were subjected to hematoxylin and eosin and immunohistological staining using Galectin-1 (Gal-1), a protein involved in cardiovascular homeostasis, and CD44, a cell-surface marker of hADSCs., Results: Comparison of inflammation-related cytokines showed a significant decrease in IL-1α expression at day 15 (P<0.05) and IL-6 expression at day 29 (P<0.01) in the hADSCs-treated group compared to the PBS group. Evaluation by hematoxylin and eosin staining showed decreased inflammatory cell infiltration and a tendency towards increased Gal-1 expression in the hADSCs group. CD44 expression was not observed in both the groups. The survival curve showed that the hADSCs group had a significantly longer survival time (P<0.05)., Conclusions: The present experimental results indicate that hADSCs have an early anti-inflammatory effect, and that Gal-1 may be involved in preventing inflammation and reducing tissue damage.

Clear-cell sarcoma of the kidney (CCSK) is a rare, aggressive pediatric renal tumor. Intratumoral hemorrhage and tumor rupture are oncologic emergencies requiring a rapid and appropriate response. An 11-year-old boy visited our hospital with abdominal distension of 1 month's duration. Computed tomography (CT) revealed a tumor in the left kidney (size: 200 mm), and analysis of a biopsy specimen confirmed a diagnosis of CCSK. Chemotherapy was initiated to shrink the large, densely vascularized tumor before surgical removal. Two days after starting chemotherapy, the patient developed abdominal and back pain, anemia, and hypotension. CT scanning showed intratumoral bleeding. Emergency transcatheter arterial embolization (TAE) was performed to control the bleeding. Three tumor feeding vessels were identified: an ascending branch from the celiac artery, an intermediate branch from the left renal artery, and a descending branch from the inferior mesenteric artery, of which the intermediate and descending branches were large and bleeding profusely. Therefore, the intermediate branch was injected with ethanol, and the descending branch was treated by gel-foam embolization. Chemotherapy was resumed, and the patient's condition gradually stabilized. The tumor began to shrink, and subsequent chemotherapy progressed well. In week 12 of chemotherapy, the patient underwent tumor resection and left nephrectomy. Postoperative chemotherapy was completed without complications, and there was no recurrence during a 6-year follow-up period. Therefore, TAE can effectively control intratumoral bleeding in pediatric solid tumors, thus preventing high-risk open surgery.

Hemophagocytic lymphohistiocytosis (HLH) associated with Epstein-Barr virus (EBV) infection can be self-limiting, severe/aggressive, or fatal. We report a case of EBV-HLH with persistent fever, severe pancytopenia, hypertriglyceridemia, and hypofibrinogenemia in a 4-year-old boy. Levels of plasma cytokines and chemokines were measured with a Bio-Plex system at 1, 2, 3, 4, 5, and 8 days after hospital admission. Administration of steroid and high-dose intravenous immunoglobulin (1 g/kg) did not alleviate fever or reduce cytokine production; however, after administration of etoposide (an antineoplastic agent), fever decreased immediately, the patient's general condition improved, and levels of IL-6, IL-10, IL-8, MCP-1, IFN-γ, and TNF-α declined after etoposide administration. In particular, IFN-γ production sharply declined, from 1,104.1 pg/mL to 101.5 pg/mL, and IL-6 level decreased from 229.8 pg/mL to 11.0 pg/mL, on the day after initial etoposide administration. There was no later recurrence of symptoms during treatment with dexamethasone, etoposide, and cyclosporine A. This case suggests that early etoposide administration is critical for treatment success and indicates that etoposide promptly inhibits cytokine production.

Background: Therapeutic outcomes for childhood malignancy have dramatically improved. However, secondary malignancies are a major concern, as they greatly affect the quality of life of survivors. This retrospective study evaluated the cumulative incidence, clinical features, and outcomes of secondary malignancies at Nippon Medical School Hospital., Methods: We examined data from 275 cases of primary childhood malignancy diagnosed between 1980 and 2014. Information regarding treatment of the primary malignancy, including irradiation dose, site, and cumulative dose of anticancer drugs, was assessed. We also collected data on secondary malignancy, including patient sex, age at diagnosis, malignancy site, time from primary to secondary malignancy, and outcomes., Results: Secondary malignancies developed in 11 patients and included acute myeloid leukemia (AML) (4), meningioma (4), Ewing sarcoma (1), germ cell tumor (1), and malignant parotid gland tumor (1). The primary malignancies included acute lymphoblastic leukemia (ALL) (9), non-Hodgkin lymphoma (1) and brain tumor (1). In 7 of the 9 ALL patients, chemoradiotherapy was the primary treatment. The meningiomas and 1 solid tumor developed within the radiation field. All AMLs and meningiomas developed within 5 years and after 20 years, respectively, of the primary diagnosis. The 10- and 20-year cumulative incidence rates for secondary malignancy in our hospital were 1.9% and 5.8%, respectively., Conclusions: Our results revealed that the type of secondary malignancy depends on the interval after the end of treatment for primary malignancy. Meningioma, notably, develops many years after completion of primary malignancy treatment. Early detection during long-term follow-up is therefore essential.