Side population (SP) is identified as cells capable of excluding the fluorescent Hoechst dye and anticancer drugs, and represents hematopoietic stem cells and chemoresistant cells from several solid tumors. In this study, we confirmed the presence of SP cells in tumors from melanoma patients. Melanoma SP cells overexpressed ATP-binding-cassette (ABC) transporters, ABCB1 and ABCB5. We generated a direct in vivo xenograft model, and demonstrated that SP cells were resistant to paclitaxel, a substrate of ABCB1, both in vitro and in vivo. However, melanoma SP cells were also resistant to temozolomide, which is not a substrate for ABC transporters, through IL-8 upregulation. In addition, gene profiling studies identified three signaling pathways (NF- κB, α6-β4-integrin and IL-1) as differentially upregulated in melanoma SP cells, and there was a significant increase of PCDHB11 and decrease of FUK and TBX2 in these cells. Therefore, we provide evidence that SP is an enriched source of chemoresistant cells in human melanomas, and suggest that the selected genes and signaling pathways of SP cells may be a potential target for effective melanoma therapies. To our knowledge, this is previously unreported study to isolate SP cells from melanoma patients and to investigate the gene expression profiling of these cells.

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a b s t r a c t R-spondin (Rspo) encodes a multi-domain protein that modulates the Wnt-signaling pathway. Two distinct rspo2 zebrafish mutants were generated by TALEN-mediated mutagenesis: a null mutant, rspo2 null , lacking all functional domains, and a hypomorphic mutant, rspo2 tsp , lacking the two N-terminal domains. Mutants were analyzed mainly for abnormalities in the skeletal system. Fin ray skeletons were formed normally in the rspo2 tsp mutants, but were absent from the rspo2 null mutants. Hypoplasia of the neural/hemal arches and ribs was observed in both mutants. Thus, the two rspo2 mutants help to identify the functions of Rspo2 in skeletogenesis, as well as functional differences among multiple Rspo2 domains.

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Percutaneous sclerotherapy has been previously described in the literature for the treatment of microcystic CPAMs with secondary hydrops. This is the first reported case of an adverse event after fetal sclerotherapy.

STAT1 gain-of-function (GOF) mutations are associated with a rare autosomal dominant immunodeficiency disorder with main clinical manifestations including chronic mucocutaneous candidiasis (CMC) and bronchiectasis. In addition, these patients show higher incidences of cerebral and extracerebral aneurysm, malignancies and various autoimmune conditions compared to the general population. Although previous publications have reported clinical findings in patients with STAT1 GOF mutation, they did not include histopathologic features. Herein, we describe the first case with detailed histologic findings in the lung of a 5-year-old patient with a de novo STAT1 GOF mutation, who presented with CMC and bronchiectasis. The biopsy showed severe bronchiolectasis with extensive airway dilatation and occasional disruptions. Peribronchiolar inflammation was not always present and evident mainly in areas of airway disruption; inflammation may have not been a main driver of the airway damage in this case. The airway dilatation often showed an interesting herniating pattern, possibly implying a connective tissue etiology. This case also demonstrates the diagnostic utility of whole exome sequencing as STAT1 GOF mutations are not detected by routine workup. The definitive diagnosis will lead to more specific treatments and increased surveillance for serious conditions, such as cerebral aneurysms and malignancies.

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