Analysis of False-negative Findings of the Incomparable Accuracy and Swiftness of Flow Cytometric Diagnosis of Primary Central Nervous System Lymphoma.

Primary central nervous system lymphoma (PCNSL), a relatively rare brain tumor, bears a dire prognosis. On occasion, the rapid progression of the tumor makes immediate diagnosis and initiation of therapy imperative. To achieve swift diagnosis, we adopt flow cytometry (FCM) in addition to conventional histopathology. This study aimed to reveal the utility of FCM diagnosis for PCNSL and the cause of false-negative results of FCM diagnosis. We investigated 33 patients with suspected PCNSL on neuroradiological findings and received both FCM and histological diagnosis. The patients' electronic medical records were investigated, and histological findings, results of FCM, and other clinical data were evaluated. Overall, 27 patients (14 males and 13 females) were diagnosed with PCNSL by histological confirmation. The median age at diagnosis was 68 years. FCM analysis showed lymphoma pattern in 24 cases; however, FCM results did not show lymphoma pattern (sensitivity: 88.9%, specificity: 100%) in the other three lymphoma cases (FCM discordant: FCM-D) and six nonlymphomatous tumor cases. Analysis of FCM-D cases showed the infiltration of T lymphocytes or astrocytes into the tumor tissue, indicating tumor microenvironmental reaction; it is assumed that these reactions deceived FCM diagnosis. The survival of FCM-D patients was superior to FCM concordant counterpart, although the difference was not significant (p = 0.459). The diagnosis of PCNSL by FCM is rapid and highly reliable. Some FCM-D cases are PCNSLs with strong tumor microenvironmental reactions.

Genetic Alteration May Proceed with a Histological Change in Glioblastoma: A Report from Initially Diagnosed as Nontumor Lesion Cases.

Despite recent signs of progress in diagnostic radiology, it is quite rare that a glioblastoma (GBM) is detected asymptomatically. We describe two patients with asymptomatic nonenhancing GBMs that were not diagnosed with neoplasia at first. The patients had brain scans as medical checkups, and incidentally lesions were detected. In both cases, surgical specimens histopathologically showed no evidence of neoplasia, whereas molecular genetic findings were isocitrate dehydrogenase (IDH)-wildtype, O6-methylguanine-DNA methyltransferase promoter (pMGMT) unmethylated, and telomerase reverse transcriptase (TERT) promoter mutated, which matched to GBM. One patient was observed without adjuvant therapy and the tumor recurred 7 months later. Reoperation was performed, and histopathologically GBM was confirmed with the same molecular diagnosis as the first surgical specimen. Another patient was carefully observed, and chemoradiotherapy was begun 6 months after the operation following the extension of the lesion. Eventually, because of disease progression, both patients deceased. We postulate that in each case, the tumor was not lower-grade glioma but corresponded to the early growth phase of GBM cells. Thus far, cases of malignant transformation from lower-grade glioma or asymptomatic GBM with typical histologic features are reported. Nevertheless, to the best of our knowledge, no such case of nonenhancing, nonhistologically confirmed GBM was reported. We conjecture these cases shed light on the yet unknown natural history of GBM. GBM can take the form of radiological nonenhancing and histological nonneoplastic fashion before typical morphology. Molecular genetic analysis can diagnose atypical preceding GBM, and we recommend early surgical removal and adjuvant treatment.

Stat5b inhibition blocks proliferation and tumorigenicity of glioblastoma stem cells derived from a de novo murine brain cancer model.

Glioblastoma (GBM) is the most common and malignant type of brain cancer in adults with poor prognosis. GBM stem cells (GSCs) reside within niches in GBM tissues and contribute to recurrence and therapy resistance. Previous studies have shown that expression of leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5), a Wnt pathway-related stem cell marker, correlates with a poor prognosis in GBM, and its knockdown in GSCs induces apoptosis accompanied with downregulation of signal transducer and activator of transcription 5b (Stat5b). Here, we show that Stat5b co-localizes with Lgr5 in hypoxia-inducible factor 2α (Hif2α)-positive regions in GBM tissues. Functional analyses using GSCs derived from a murine de novo GBM model induced by oncogenic genes transduction using the Sleeping-Beauty transposon system revealed that expression of Stat5b was induced by culturing under hypoxia together with Lgr5, repressed by Hif2α knockdown, and reduced by Lgr5 knockdown or a Wnt/ß-catenin signaling inhibitor ICG-001 treatment. Stat5b inhibition in the GSCs induced apoptosis and caused downregulation of Cyclin E2 resulted in blockade of entry into S-phase in the cell cycle. Disruption of Stat5b in an orthotopic transplantation model significantly prolongs event-free survival. These results suggest that Stat5b, regulated by hypoxia and the Wnt pathway, plays an important role in the maintenance and tumorigenicity of GSCs and may be a promising therapeutic molecular target to attack GSCs.

Inhibition of Gli2 suppresses tumorigenicity in glioblastoma stem cells derived from a de novo murine brain cancer model.

The prognosis of glioblastoma remains poor despite intensive research efforts. Glioblastoma stem cells (GSCs) contribute to tumorigenesis, invasive capacity, and therapy resistance. Leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5), a stem cell marker, is involved in the maintenance of GSCs, although the properties of Lgr5-positive GSCs remain unclear. Here, the Sleeping-Beauty transposon-induced glioblastoma model was used in Lgr5-GFP knock-in mice identify GFP-positive cells in neurosphere cultures from mouse glioblastoma tissues. Global gene expression analysis showed that Gli2 was highly expressed in GFP-positive GSCs. Gli2 knockdown using lentiviral-mediated shRNA downregulated Hedgehog-related and Wnt signaling pathway-related genes, including Lgr5; suppressed tumor cell proliferation and invasion capacity; and induced apoptosis. Pharmacological Gli inhibition with GANT61 suppressed tumor cell proliferation. Silencing Gli2 suppressed the tumorigenicity of GSCs in an orthotopic transplantation model in vivo. These findings suggest that Gli2 affects the Hedgehog and Wnt pathways and plays an important role in GSC maintenance, suggesting Gli2 as a therapeutic target for glioblastoma treatment.

Progress in the treatment of unruptured aneurysms.

Recent technological progress has reduced the complication rate of unruptured aneurysm. We treated 128 unruptured aneurysms between April 2006 and March 2012. Seventy-six aneurysms (59 %) were clipped and 52 (41 %) were coil embolized. After 2010, we applied new instruments, i.e., near-infrared indocyanine-green videoangiography (ICG), an intraoperative endoscope, preoperative detailed MRI, and a stent-assisted coil embolization. In the results: (1) In 60 aneurysms treated before 2009, three patients showed a deterioration of more than two points in mRS (5 %). In 68 aneurysms treated after 2010, no patients showed deterioration (0 %) (p: n.s.). (2) No patients died and 126 patients (98 %) were discharged to home directly. (3) No patients showed rupture after treatment. In conclusion, the appropriate selection of treatment and recent technological progress have facilitated sophisticated treatment of unruptured aneurysms. Recently, the complication rate in surgery and endovascular surgery for unruptured aneurysms has become acceptably low.