Pleomorphic xanthoastrocytoma (PXA) is low-grade glial neoplasm principally affecting children and young adults. Approximately 40% of PXA are reported to recur within 10 years of primary resection. Upon recurrence, patients receive radiation therapy and conventional chemotherapeutics designed for high-grade gliomas. Genetic changes that can be targeted by selective therapeutics have not been extensively evaluated in PXA and ancillary diagnostic tests to help discriminate PXA from other pleomorphic and often more aggressive astrocytic malignancies are limited. In this study, we apply the SNaPshot multiplexed targeted sequencing platform in the analysis of brain tumors to interrogate 60 genetic loci that are frequently mutated in 15 cancer genes. In our analysis we detect BRAF V600E mutations in 12 of 20 (60%) WHO grade II PXA, in 1 of 6 (17%) PXA with anaplasia and in 1 glioblastoma arising in a PXA. Phospho-ERK was detected in all tumors independent of the BRAF mutation status. BRAF duplication was not detected in any of the PXA cases. BRAF V600E mutations were identified in only 2 of 71 (2.8%) glioblastoma (GBM) analyzed, including 1 of 9 (11.1%) giant cell GBM (gcGBM). The finding that BRAF V600E mutations are common in the majority of PXA has important therapeutic implications and may help in differentiating less aggressive PXAs from lethal gcGBMs and GBMs.

Iron availability is critical to Pseudomonas aeruginosa. The current authors determined sputum iron, ferritin, microalbumin levels and total cell counts (TCC) in 19 adult patients with cystic fibrosis (CF) during an acute exacerbation and repeated analyses following a median of 12 days antibiotic treatment. The current authors also determined sputum interleukin (IL)-1b and tumour necrosis factor (TNF)-a levels because of their putative role in intracellular iron homeostasis. Additional data were obtained from 17 stable CF patients, eight patients with stable chronic obstructive pulmonary disease (COPD) and six normal subjects.Overall, sputum iron, ferritin, microalbumin, IL-1b and TNF-a concentrations and TCCs were significantly elevated in the CF patients compared to those with COPD and normal controls. Sputum ferritin levels were significantly elevated in acute versus stable CF patients and there was a trend for sputum TCC to be higher, but all other inflammatory indices were similar. In the CF patients, sputum iron was positively and strongly related to IL-1b, TNF-a, ferritin and microalbumin levels, but negatively related to forced expiratory volume in one second % predicted. In those acute patients who clinically improved with antibiotics (n=14), there were significant decreases in sputum TCC, iron, ferritin and IL-1b content, but not TNF-a or albumin levels. However, changes in sputum TNF-a in acute patients were still closely related to changes in iron, ferritin and albumin content, and changes in IL-1b were related to changes in sputum ferritin content.Iron and iron-regulatory cytokines may play a role in cystic fibrosis lung disease and the increased iron content may even facilitate Pseudomonas aeruginosa infection.

Purpose Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine tumor, often metastatic at presentation, for which current chemotherapeutic regimens are largely ineffective. As its pathogenesis is still unknown, we hypothesized that deregulation of signaling pathways commonly activated in cancer may contribute to MCC tumorigenesis and may provide insights into targeted therapy approaches for this malignancy. Experimental Design We retrospectively profiled 60 primary MCC samples using a SNaPshot-based tumor genotyping assay to screen for common mutations in 13 cancer genes. Results We identified mutations in 9 (15%) MCC primary tumors, including mutations in TP53 (3/60) and activating mutations in the PIK3CA gene (6/60). Sanger sequencing of the primary MCC tumors detected one additional PIK3CA mutation (R19K) that had not been previously described in cancer. Merkel cell polyoma virus (MCPyV) was detected in 38 (66%) MCC cases and patients with MCPyV-positive cancers showed a trend toward better survival. With one exception, the presence of MCPyV and of activating mutations in PIK3CA appeared mutually exclusive. We observed that signaling through the PI3K/pAKT pathway was active in one MCPyV-positive and in all MCPyV-negative MCC cell lines, as evidenced by AKT phosphorylation. Importantly, the presence of a PIK3CA activating mutation was associated with sensitivity to treatment with ZST474, a specific PI3K inhibitor and to NVP-BEZ235, a dual PI3K-mTOR inhibitor, targeted agents under active clinical development. Conclusions PI3K pathway activation may drive tumorigenesis in a subset of MCC and screening these tumors for PIK3CA mutations could help identify patients who may respond to treatment with PI3K pathway inhibitors.