A case of recurrent histiocytic sarcoma with MAP2K1 pathogenic variant treated with the MEK inhibitor trametinib.

Histiocytic sarcoma in advanced clinical stages is typically an aggressive neoplasm, with poor response to conventional chemotherapy. An 18-year-old male with refractory histiocytic sarcoma that had transformed from Rosai-Dorfman disease was admitted to our hospital. A pathogenic variant of MAP2K1 was detected by next-generation sequencing of tumor specimens. Affected regions showed excellent responses to the MEK inhibitor trametinib. It has been reported that RAS/MEK/ERK pathway is activated in many cases of histiocytic sarcoma. MEK inhibition may represent a useful treatment option in histiocytic sarcoma.

Therapy-related Secondary Malignancy After Treatment of Childhood Malignancy: Cases from a Single Center.

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.

Melatonin overcomes resistance to clofarabine in two leukemic cell lines by increased expression of deoxycytidine kinase.

Drug resistance remains a serious problem in leukemia therapy. Among newly developed nucleoside antimetabolites, clofarabine has broad cytotoxic activity showing therapeutic promise and is currently approved for relapsed acute lymphoblastic leukemia. To investigate the mechanisms responsible for clofarabine resistance, we established two clofarabine-resistant lymphoblastic leukemia cell lines from parental lines. To elucidate the mechanisms against clofarabine resistance in two newly established clofarabine-resistant cell lines, we measured the expression of export pumps multidrug resistance protein 1, multidrug resistance-associated protein 1, and ATP-binding cassette subfamily G member 2. There were no differences in the expression between clofarabine-sensitive and -resistant cell lines. Next, we determined expression of deoxycytidine kinase (dCK), which phosphorylates clofarabine to exert cytotoxicity, in clofarabine-sensitive and -resistant cells. Clofarabine-resistant cells showed significantly decreased expression of dCK RNA when compared with sensitive cells. To elucidate the mechanisms of decreased dCK expression in clofarabine-resistant cells, we analyzed the methylation status of CpG islands of the dCK promoter and found no differences in methylation status between clofarabine-sensitive and -resistant cells. Next, we measured the acetylation status of histone and found that total histone acetylation, and histone H3 and H4 acetylation on chromatin immunoprecipitation assay were significantly decreased in resistant cells. Melatonin is an indolamine that functions in the regulation of chronobiological rhythms to exert cytotoxic effects. We examined the effects of melatonin in clofarabine-resistant cells and found that melatonin treatment led to significantly increased cytotoxicity with clofarabine in resistant cells via increased acetylation. Melatonin may be a useful candidate for overcoming clofarabine resistance in two newly established clofarabine resistant leukemia cell lines.

Efficacy of eculizumab in a patient with paroxysmal nocturnal hemoglobinuria requiring transfusions 14 years after a diagnosis in childhood.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired clonal disorder characterized by chronic complement-mediated hemolysis. The humanized anti-C5 antibody eculizumab binds to the C5 protein and suppresses hemolysis by inhibiting C5b-9 generation. Here, we report on a 27-year-old woman who was found to have PNH in 1997 (at 13 years of age), without subsequent transfusions, thrombosis, or renal disorder. She had been experiencing frequent malaise and fatigue and was sometimes unable to participate in social activities. She had also experienced repeated hemolytic episodes due to infection, and the hemoglobin level had decreased from 7.0 to 5.0 g/dL several times since February 2010. Red blood cell transfusion was necessary, and 6 months later, treatment with eculizumab was started. The hemoglobin level stabilized, and the patient became transfusion-independent. Furthermore, the patient showed significant improvements in fatigue scale scores and quality of life. Six months after the start of eculizumab therapy, the percentage of PNH-type red blood cells was found to have increased from 82.0% (1.95 × 10(12) cells/L) to 89.1% (2.78 × 10(12) cells/L). Furthermore, during treatment with eculizumab, intravascular hemolysis occurred due to a viral infection accompanied by a high fever. We also observed a persistent elevation in reticulocytes and total bilirubin levels, as well as a persistent reduction in haptoglobin levels. Extravascular hemolytic findings were also observed. Because treatment with eculizumab was started at a young age (27 years) and will be continued for many years, careful observation of the patient is required.

A 6-year-old girl with hemoglobin H disease.

Hemoglobin H (HbH) disease is the severe nonfatal form of α-thalassemia syndrome. It is usually caused by molecular defects of 3 of 4 α-globin genes (--/-α) which cause α-globin expression to be decreased. HbH disease is rare in Japan. Here, we report on a 6-year-old girl with HbH disease who had profound hypochromatic and microcytic anemia. Analysis of the α-globin genes of the patient's family showed that the father, who was Japanese, had an abnormal gene with a 3.7-kb deletion (-α(3.7)/αα), and the mother, who was Filipino, had a deletion removing both α-globin genes of the Filipino type (--(FIL)/αα). Neither parent had anemia. The patient was found to have HbH disease with a heterozygous genetic abnormality (--(FIL)/-α(3.7)). Recently, the number of marriages of Japanese to natives of areas where thalassemia is epidemic has increased. Therefore, the incidence of HbH disease can be expected to increase in Japan. Long-term follow-up will be needed to evaluate the long-term complications and to improve the quality of life of patients with HbH disease.