s ?gnised types or, as we should prefer to call them, genera, ^Cles and varieties of tumours. In carrying out this project, \\ve Particularly when making out the series of indexes that e required, we soon made acquaintance with difficulties of enclature and of classification. These difficulties occur 0Ve?*t daily in the course of routine examinations and are th^00.1116 or evaded in varying fashion. It may be argued cl \\ln the present state of our knowledge, a satisfactory j^Slficati?n of tumours is not possible, or that it is easy to Co^ e Ossifications from an armchair for one who is not deeply p0j^erned in using them. But those remarks seem to miss the

Classification of Tumours.

Infantile hemangiomas (IH) affect up to 10% of infants. A rapid proliferative phase is followed by slow spontaneous involution. Approximately 12% of IH

A Randomized, Controlled Trial of Oral Propranolol for Infantile Hemangioma

Cri-du-chat (cat's cry) syndrome, also known as 5p(5p minus) syndrome, is a chromosomal condition that results when a piece of chromosome 5 is missing. Infants with this condition often have a high-pitched cry that sounds like that of a cat. The disorder is characterized by intellectual disability and delayed development, small head size (microcephaly), low birth weight, and weak muscle tone (hypotonia) in infancy. Affected individuals also have distinctive facial features, including widely set eyes (hypertelorism), low-set ears, a small jaw, and a rounded face. Some children with cridu-chat syndrome are born with a heart defect.

[The cri-du-chat syndrome].

Vascular malformations are thought to be monogenic disorders that result in dysregulated growth of blood vessels. In the brain, cerebral cavernous malformations (CCMs) arise owing to inactivation of the endothelial CCM protein complex, which is required to dampen the activity of the kinase MEKK31–4. Environmental factors can explain differences in the natural history of CCMs between individuals5, but why single CCMs often exhibit sudden, rapid growth, culminating in strokes or seizures, is unknown. Here we show that growth of CCMs requires increased signalling through the phosphatidylinositol-3-kinase (PI3K)–mTOR pathway as well as loss of function of the CCM complex. We identify somatic gain-of-function mutations in PIK3CA and loss-of-function mutations in the CCM complex in the same cells in a majority of human CCMs. Using mouse models, we show that growth of CCMs requires both PI3K gain of function and CCM loss of function in endothelial cells, and that both CCM loss of function and increased expression of the transcription factor KLF4 (a downstream effector of MEKK3) augment mTOR signalling in endothelial cells. Consistent with these findings, the mTORC1 inhibitor rapamycin effectively blocks the formation of CCMs in mouse models. We establish a three-hit mechanism analogous to cancer, in which aggressive vascular malformations arise through the loss of vascular ‘suppressor genes’ that constrain vessel growth and gain of a vascular ‘oncogene’ that stimulates excess vessel growth. These findings suggest that aggressive CCMs could be treated using clinically approved mTORC1 inhibitors. Aggressive cerebral cavernous malformations (CCMs) are found to grow through a three-hit cancer-like mechanism, involving gain of function of a gene that promotes vascular growth, and loss of function of genes that suppress it.

PIK3CA and CCM mutations fuel cavernomas through a cancer-like mechanism

Lymphatic vessels maintain tissue fluid homeostasis by returning to blood circulation interstitial fluid that has extravasated from the blood capillaries. They provide a trafficking route for cells of the immune system, thus critically contributing to immune surveillance. Developmental or functional defects in the lymphatic vessels, their obstruction or damage, lead to accumulation of fluid in tissues, resulting in lymphedema. Here we discuss developmental lymphatic anomalies called lymphatic malformations and complex lymphatic anomalies that manifest as localized or multifocal lesions of the lymphatic vasculature, respectively. They are rare diseases that are caused mostly by somatic mutations and can present with variable symptoms based upon the size and location of the lesions composed of fluid-filled cisterns or channels. Substantial progress has been made recently in understanding the molecular basis of their pathogenesis through the identification of their genetic causes, combined with the elucidation of the underlying mechanisms in animal disease models and patient-derived lymphatic endothelial cells. Most of the solitary somatic mutations that cause lymphatic malformations and complex lymphatic anomalies occur in genes that encode components of oncogenic growth factor signal transduction pathways. This has led to successful repurposing of some targeted cancer therapeutics to the treatment of lymphatic malformations and complex lymphatic anomalies. Apart from the mutations that act as lymphatic endothelial cell-autonomous drivers of these anomalies, current evidence points to superimposed paracrine mechanisms that critically contribute to disease pathogenesis and thus provide additional targets for therapeutic intervention. Here, we review these advances and discuss new treatment strategies that are based on the recently identified molecular pathways.

Lymphatic Malformations: Genetics, Mechanisms and Therapeutic Strategies.

Lymphatic anomalies (LAs) include several disorders in which abnormal lymphatic tissue invades the neck, chest, and various organs. Progressive cases may result in lethal outcomes and have proven difficult to treat. Sirolimus is showing promising results in the management of vascular anomalies. We examined the efficacy and safety of sirolimus treatment in patients with progressive LAs. All patients with LAs treated with sirolimus from May 2015 to September 2018 were included. They received oral sirolimus once a day and the dose was adjusted so that the trough concentration remained within 5–15 ng/mL. We prospectively reviewed the response to drugs (the response rate of radiological volumetric change of the target lesion), severity scores, reported quality of life (QOL), and adverse effects at 6 months after administration. Twenty patients (five with cystic lymphatic malformation (LM), three with kaposiform lymphangiomatosis, three with generalized lymphatic anomaly, six with Gorham-Stout disease, and three with central conducting lymphatic anomaly) were treated with sirolimus at our institution. Fifty percent of patients (10/20) demonstrated a partial response by a radiological examination and a significant improvement in disease severity and QOL scores (P = 0.0020 and P = 0.0117, respectively). Ten patients who had no reduction in lesion size (stable disease group) showed no significant improvement in disease severity and QOL scores. Eighty percent of patients (16/20) had side effects, such as stomatitis, infection, and hyperlipidemia. Sirolimus impacts the reduction of the lymphatic tissue volume of LMs and could lead to improvement in clinical symptoms and QOL. UMIN Clinical Trials Registry, UMIN000016580
 . Registered 19 February 2015,

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The impact of sirolimus therapy on lesion size, clinical symptoms, and quality of life of patients with lymphatic anomalies.

Kaposiform lymphangiomatosis (KLA) has recently been distinguished as a novel subtype of generalized lymphatic anomaly (GLA) with foci of spindle endothelial cells. All cases of KLA involve multiple organs and have an unfavorable prognosis. However, the molecular pathogenesis is unknown, and there are no useful biomarkers. In the present study, we performed genetic analysis to elucidate the cause of this disease and detect biomarkers for it. We performed whole-exome sequencing of DNA samples from leukocytes and a biopsy specimen and analyzed cell-free DNA (cfDNA) from plasma and pleural effusion of patients to identify the NRAS c.182A > G (p.Q61R) mutation using the droplet digital polymerase chain reaction (ddPCR). All KLA patients (patients 1–5) had invasive and aggressive features (hemorrhagic pleural effusions, coagulation disorder, and thrombocytopenia) and characteristic findings of KLA in their pathological examinations. In whole exome sequencing for patient 1, c.182A > G missense variant (p.Q61R) in NRAS was identified in fresh frozen samples of a mass on the left chest wall at a frequency of 5% of total alleles but not in his blood leukocytes. Furthermore, the same mutation was detected in cfDNA isolated from plasma and pleural effusion by using ddPCR. ddPCR analysis of plasma/pleural effusion samples from an additional four KLA patients showed that the same mutation was detected in isolated cfDNA in three of the four, as well as in a tissue sample from one of the three plasma/effusion-positive patients that had been obtained to confirm the mutation. These results provide the first evidence that NRAS oncogenic variant was identified in DNA samples from KLA patients from not only two affected lesions but also plasma and pleural effusion.

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Detection of NRAS mutation in cell-free DNA biological fluids from patients with kaposiform lymphangiomatosis.

BACKGROUND/AIM Activation of AKT serine/ threonine kinase (AKT) predicts poor outcome in neuroblastoma, which highlights the potential of the AKT pathway as a promising target for neuroblastoma treatment. Several studies reported that blockade of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptors (AMPARs) reduces proliferation in glioblastoma or lung cancer by inhibiting AKT and extracellular signal-related kinase (ERK) pathways. In this study, we examined the effect of the AMPAR antagonist perampanel on human neuroblastoma cells. MATERIALS AND METHODS Cell proliferation, caspase activity, and western blot assays were performed to determine the effect of perampanel on the KP-N-SI9s human neuroblastoma cell line. RESULTS Perampanel inhibited cell proliferation without triggering apoptosis in neuroblastoma cells. Down-regulation of AKT protein levels, AKT phosphorylation, and ERK1/2 phosphorylation were also observed in neuroblastoma cells with perampanel treatment. CONCLUSION Perampanel inhibits neuroblastoma cell proliferation through down-regulation of AKT and ERK pathways and has potential for the treatment of neuroblastoma.

Perampanel Inhibits Neuroblastoma Cell Proliferation Through Down-regulation of AKT and ERK Pathways.

Few hematological complications have previously been reported in association with Cri du Chat syndrome (CdCS). A case of myelodysplastic syndromes (MDS) in a pediatric patient with CdCS is herein presented. A 17-year-old female with CdCS caused by ring chromosome 5 was admitted to the hospital for investigation of a 1-month history of anemia. Based on the morphological findings of bone marrow, the patient was diagnosed with refractory cytopenia with multilineage dysplasia. The risk group was classified as intermediate-1 in the International Prognostic Scoring System (IPSS), and low in the revised IPSS. Assessment by microarray comparative genomic hybridization (CGH) identified the breakpoints of ring chromosome 5 as 46,XX,r(5)(p14.3q35.3). This revealed that the 5q terminal deletion did not include the common deleted region of MDS with del(5q). Treatment with azacitidine was initiated to control disease progression and improve quality of life. At baseline, the patient had a mean transfusion requirement of 3 units/month, which decreased to 2 units/month after six cycles of azacitidine and to 1 unit/month after 10 cycles of azacitidine. Cytopenia observed in the presented case seemed irrelevant to ring chromosome 5 which is the causative cytogenetic abnormality of CdCS, and further analyses may be needed to clarify the pathogenesis.

Myelodysplastic syndromes in a pediatric patient with Cri du Chat syndrome with a ring chromosome 5

Background Kaposiform lymphangiomatosis (KLA) is a recently characterized systemic lymphatic anomaly. Activation of RAS/MAPK and PI3K/AKT/mTOR pathways may affect KLA pathogenesis, but the cellular basis of KLA is unclear. Abnormal-spindle endothelial cells that express lymphatic endothelial cell (LEC) markers are characteristic of KLA histopathology. This study evaluated patient-derived KLA cells to establish their morphological and biological characteristics. Procedure We established cell lines from primary KLA tissues of two patients with KLA and examined their morphological and functional characteristics, messenger RNA and protein expression profiles, gene mutations, and responses to inhibitors of the RAS/MAPK and PI3K/AKT/mTOR pathways. Results Both KLA cell lines showed spindle-shaped morphology, stained positive for podoplanin (PDPN), and exhibited impaired tube-formation properties. They expressed LEC marker PDPN and mesenchymal stem cell markers (CD90, CD105) in the absence of endothelial cell markers (CD34, CD31, VWF), per real-time polymerase chain reaction. Both mTOR inhibitor rapamycin and MEK inhibitor trametinib inhibited growth of the two cell lines. A NRAS p.Q61R variant was found in one of two independent KLA tissue samples, but not in the KLA cells (per targeted next-generation sequencing); and KLA cells with this variant had elevated AKT phosphorylation levels. ERK phosphorylation levels were undetectable in both KLA cell lines. Conclusions Inhibition of the RAS/MAPK and PI3K/AKT/mTOR pathways may represent potential therapeutic targets in KLA. These patient-derived KLA cell lines will be useful research tools to elucidate KLA etiology, and could pave the way for basic, translational, and preclinical studies of this disease.

Saori Endo

Papers

The impact of sirolimus therapy on lesion size, clinical symptoms, and quality of life of patients with lymphatic anomalies.

Detection of NRAS mutation in cell-free DNA biological fluids from patients with kaposiform lymphangiomatosis.

Perampanel Inhibits Neuroblastoma Cell Proliferation Through Down-regulation of AKT and ERK Pathways.

Myelodysplastic syndromes in a pediatric patient with Cri du Chat syndrome with a ring chromosome 5

Characterization of kaposiform lymphangiomatosis tissue-derived cells.