Combined DNA methylation and gene expression profiling in gastrointestinal stromal tumors reveals hypomethylation of SPP1 as an independent prognostic factor

Gastrointestinal stromal tumors (GISTs) have distinct gene expression patterns according to localization, genotype and aggressiveness. DNA methylation at CpG dinucleotides is an important mechanism for regulation of gene expression. We performed targeted DNA methylation analysis of 1.505 CpG loci in 807 cancer‐related genes in a cohort of 76 GISTs, combined with genome‐wide mRNA expression analysis in 22 GISTs, to identify signatures associated with clinicopathological parameters and prognosis. Principal component analysis revealed distinct DNA methylation patterns associated with anatomical localization, genotype, mitotic counts and clinical follow‐up. Methylation of a single CpG dinucleotide in the non‐CpG island promoter of SPP1 was significantly correlated with shorter disease‐free survival. Hypomethylation of this CpG was an independent prognostic parameter in a multivariate analysis compared to anatomical localization, genotype, tumor size and mitotic counts in a cohort of 141 GISTs with clinical follow‐up. The epigenetic regulation of SPP1 was confirmed in vitro, and the functional impact of SPP1 protein on tumorigenesis‐related signaling pathways was demonstrated. In summary, SPP1 promoter methylation is a novel and independent prognostic parameter in GISTs, and might be helpful in estimating the aggressiveness of GISTs from the intermediate‐risk category.     

Evaluation of thoracic tumors with 18F-fluorothymidine and 18F-fluorodeoxyglucose-positron emission tomography

STUDY OBJECTIVES: 18F-fluorodeoxyglucose (FDG) is the most widely used positron emission tomography (PET) imaging probe used for the diagnosis, staging, restaging, and monitoring therapy response of cancer. However, its specificity is less than ideal. A new molecular imaging probe (18F-deoxyfluorothymidine [FLT]) has been developed that might afford more specific tumor imaging. The aims of this study were as follows: (1) to compare the use of FDG-PET and FLT-PET for tumor staging, (2) to compare the degree of FDG and FLT uptake in lung lesions, and (3) to determine the correlation between PET uptake intensity and tumor cell proliferation. DESIGN: FDG-PET and FLT-PET scans were performed in 11 patients with solitary pulmonary nodules and another 11 patients with known non-small cell lung cancer (NSCLC). Tracer uptake was assessed quantitatively by standardized uptake values (SUVs). Histologic evaluation of tissue samples obtained from biopsy specimens or surgical resections served as the "gold standard." Tumor cell proliferation was assessed by Ki-67 staining. RESULTS: Pathology verification was available from 99 tissue samples in the 22 patients (29 pulmonary lesions, 66 lymph node stations, and 4 extrapulmonary lesions). Thirty-three samples (33.3%) were positive for tumor tissue (22 pulmonary, 9 lymph node stations, and 2 extrapulmonary). FDG-PET findings were false-positive in three pulmonary lesions, while FLT-PET findings were false-positive in one lesion. There were two false-negative findings by FDG-PET and six false-negative findings by FLT-PET. FDG uptake of the malignant lesions was significantly higher than FLT (maximum SUV, 3.1 +/- 2.6 vs 1.6 +/- 1.2 [mean +/- SD]; p < 0.05). A significant correlation was observed between FLT uptake of pulmonary lesions and Ki-67 labeling index (r = 0.60, p = 0.02) but not for FDG uptake (r = 0.27, p = not significant). CONCLUSIONS: Compared to FDG-PET, detection of primary and metastatic NSCLC by FLT-PET is limited by the relatively low FLT uptake of the tumor tissue. Thus, FLT-PET is unlikely to provide more accurate staging information or better characterization of pulmonary nodules than FDG-PET. Nevertheless, the correlation between FLT uptake and cellular proliferation suggests that future studies should evaluate the use of FLT-PET for monitoring treatment with cytostatic anticancer drugs.     

Management of thymomas

Thymoma is a rare neoplasm usually with an indolent growth pattern, however, local invasion and/or metastases may occur. The association with several paraneoplastic syndromes, especially myasthenia gravis, is noteworthy. Surgery has been the standard of care for early stage disease with high cure rates anticipated. The most important prognostic factors after resection are Masaoka stage, World Health Organization (WHO) histology, complete resection status and size. Multimodality therapy can result in long-term disease-free survival for patients presenting with locally advanced disease. Thymomas are sensitive to both chemotherapy and radiation therapy and are utilized with good effects in unresectable patients.     

Restricted dendritic cell and monocyte progenitors in human cord blood and bone marrow

In mice, two restricted dendritic cell (DC) progenitors, macrophage/dendritic progenitors (MDPs) and common dendritic progenitors (CDPs), demonstrate increasing commitment to the DC lineage, as they sequentially lose granulocyte and monocyte potential, respectively. Identifying these progenitors has enabled us to understand the role of DCs and monocytes in immunity and tolerance in mice. In humans, however, restricted monocyte and DC progenitors remain unknown. Progress in studying human DC development has been hampered by lack of an in vitro culture system that recapitulates in vivo DC hematopoiesis. Here we report a culture system that supports development of CD34⁺ hematopoietic stem cell progenitors into the three major human DC subsets, monocytes, granulocytes, and NK and B cells. Using this culture system, we defined the pathway for human DC development and revealed the sequential origin of human DCs from increasingly restricted progenitors: a human granulocyte-monocyte-DC progenitor (hGMDP) that develops into a human monocyte-dendritic progenitor (hMDP), which in turn develops into monocytes, and a human CDP (hCDP) that is restricted to produce the three major DC subsets. The phenotype of the DC progenitors partially overlaps with granulocyte-macrophage progenitors (GMPs). These progenitors reside in human cord blood and bone marrow but not in the blood or lymphoid tissues.DCs, monocytes, and macrophages are closely related cell types whose interrelationship were long debated and only recently elucidated in the mouse (Geissmann et al., 2010; Merad et al., 2013). In mice, DCs and monocytes arise from a macrophage/dendritic progenitor (MDP; Fogg et al., 2006), which produces monocytes, and a common dendritic progenitor (CDP) that is restricted to the DC fate (Shortman and Naik, 2007; Liu et al., 2009; Geissmann et al., 2010; Merad et al., 2013). The CDP produces pre–plasmacytoid DCs (pDCs) and pre–conventional DCs (cDCs), the latter of which leaves the BM and circulates in the blood before entering tissues and developing into the different DCs subsets (Naik et al., 2006, 2007; Onai et al., 2007b, 2013; Ginhoux et al., 2009; Liu et al., 2009; Onai et al., 2013).In the mouse, DC differentiation is dependent on a hematopoietin, Flt3L, whose receptor, Flt3 (CD135), is expressed throughout DC development (McKenna et al., 2000; Karsunky et al., 2003; Waskow et al., 2008). In contrast, other hematopoietin receptors such as monocyte colony-stimulating factor receptor (M-CSFR or CD115) and granulocyte macrophage colony-stimulating factor receptor (GM-CSFR or CD116) are restricted to hematopoietic progenitors of DCs but not expressed on all mature DCs (Kingston et al., 2009).DC development in the human is far less well understood than in the mouse. Human monocytes can be induced to differentiate into potent antigen-presenting cells with some phenotypic features of DCs after in vitro culture with cocktails of cytokines (Sallusto and Lanzavecchia, 1994). However, these monocyte-derived DCs are more closely related to activated monocytes than to cDCs (Naik et al., 2006; Xu et al., 2007; Cheong et al., 2010; Crozat et al., 2010). Progress in defining the human DC lineage has been hampered, in part, by a paucity of reliable markers to distinguish these cells from monocytes, limited access to human tissues, the relatively small number of circulating DCs in blood, and the lack of a robust tissue culture system for the in vitro development of all DC subsets (Poulin et al., 2010; Ziegler-Heitbrock et al., 2010; Proietto et al., 2012).Here we report a stromal cell culture system that supports the development of CD34⁺ hematopoietic stem cell (HSC) progenitors into the three major subsets of human DCs, monocytes, granulocytes, and NK and B cells. Using this culture system, we have been able to define the sequential origin of human DCs from a human granulocyte-monocyte-DC progenitor (hGMDP), which develops into a more restricted human monocyte-dendritic progenitor (hMDP), which produces monocytes, and a human CDP (hCDP), which is restricted to produce the three major subsets of DCs.     

Evading and embracing normality: estrangement and ambivalence in the accounts of methamphetamine consumers

While much has been made of the governmentality evinced in drug policy, its effects on people who use drugs have received less attention. Scholars who have investigated these effects commonly focus on the views and experiences of individuals receiving treatment for their drug use, often reporting an explicit desire among individuals in treatment for a return to a normal, healthy life. Many authors trace this desire to the normalisation inherent in drug policy, and the governmentality involved in the delivery of drug treatment more directly. This article adds to these discussions by shifting focus from the experience of individuals in treatment to those out of treatment settings. In so doing, we aim to develop a more nuanced understanding of how heavy drug users negotiate power, governmentality and the modulations of health and illness in the course of everyday life. We ground our discussion in qualitative research conducted in Melbourne, Australia, with 31 current methamphetamine consumers. We argue that regular methamphetamine consumption involves a complex and ambivalent relationship with the ideas of health and normal life, imposing as well as reflecting a form of estrangement between its consumers and mainstream (or normal) society. This ambivalence has important implications for the delivery of health and social services among methamphetamine consumers, insofar as the restoration of normal health and the reintegration of former drug users into mainstream society are typical health service goals. We address some of these policy implications by way of conclusion.