Musashi-1 Is a Novel Immunohistochemical Marker of Neuroendocrine Carcinoma of the Lung.

Small cell lung cancer (SCLC) and large cell neuroendocrine carcinoma (LCNEC) have recently been grouped as lung neuroendocrine carcinomas (NECs). Because these lung NECs are clinically malignant and their treatment strategies differ from those of non-SCLC, the quality of diagnosis has a significant prognostic impact. The diagnosis of LCNEC requires positive immunohistochemical staining with chromogranin A, synaptophysin, and CD56, along with a morphological diagnosis, and insulinoma-associated protein 1 (INSM1) has been proposed as an additional marker but is still not an ideal or better marker. We investigated Musashi-1 as a novel immunohistochemical marker in 42 patients with SCLCs and 44 with LCNECs who underwent lung resection between 1998 and 2020 at our institution. We found Musashi-1 expression in 98% (41/42) SCLC and in 90% (40/44) LCNEC. These findings were similar to CD56 expression and superior to synaptophysin, chromogranin A, and INSM1. Musashi-1 also tended to show more diffuse and intense staining, especially in LCNEC, with more cases staining > 10% than any other existing markers (Musashi-1, 77%; INSM1, 45%; chromogranin A, 34%; synaptophysin, 41%; and CD56, 66%). In conclusion, we identified Musashi-1 as a novel immunohistochemical staining marker to aid in the diagnosis of lung NEC.

Long Non-coding RNA LINC00152 Requires EZH2 to Promote Mesothelioma Cell Proliferation, Migration, and Invasion.

BACKGROUND/AIM: Long non-coding RNAs (lncRNAs) establish gene regulatory networks in different human cancers and are involved in tumorigenesis. lncRNA LINC00152 is over-expressed in several malignant tumors and involved in tumorigenesis; however, its underlying regulatory mechanisms remain unclear. Mesothelioma, a cancer originating from mesothelial cells, is highly aggressive with a poor prognosis. Therefore, identification of new therapeutic targets is necessary for mesothelioma treatment. MATERIALS AND METHODS: Here, we conducted bioinformatics analyses of LINC00152 and enhancer of zeste homolog 2 (EZH2) expression levels and their correlation with the prognosis of patients with mesothelioma. Small interfering RNAs targeting LINC00152 and EZH2 were transfected into mesothelioma cell lines to analyze their biological functions and regulatory mechanisms. RESULTS: High LINC00152 expression was associated with a poor prognosis of patients with mesothelioma. LINC00152 knockdown inhibited the proliferation, migration, and invasion of mesothelioma cell lines. These results suggest that LINC00152 is a tumor-promoting factor in mesothelioma. EZH2 is highly expressed in mesothelioma and other malignancies. Direct interaction between LINC00152 and EZH2 is associated with cancer development and progression. When EZH2 expression was suppressed, LINC00152 knockdown did not suppress the proliferation, migration, and invasion of mesothelioma cells. Therefore, the tumor-promoting effect of LINC00152 in mesothelioma was dependent on EZH2 expression. CONCLUSION: LINC00152 promotes mesothelioma cell proliferation, migration, and invasion in cooperation with EZH2, highlighting its potential as an effective therapeutic target for mesothelioma.

Differences in invasiveness and recurrence rate among nonfunctioning pituitary neuroendocrine tumors depending on tumor subtype.

PURPOSE: To clarify the invasiveness to surrounding structures and recurrence rate of each subtype of nonfunctioning pituitary neuroendocrine tumor (Pit-NETs) according to the WHO 2022 classification. METHODS: This retrospective study utilized data from 292 patients with nonfunctioning Pit-NETs treated with initial transsphenoidal surgery. Recurrence was evaluated on 113 patients who were available for a magnetic resonance imaging follow-up ≥ 60 months. All tumors were assessed by immunohistochemical staining for Pit-1, T-PIT, and GATA3. Invasiveness to surrounding structures was evaluated based on intraoperative findings. RESULTS: Cavernous sinus invasion was found in 47.5% of null cell tumors, 50.0% of Pit-1 lineage tumors, 31.8% of corticotroph tumors, and 18.3% of gonadotroph tumors. Dura mater defects in the floor of sellar turcica, indicating dural invasion, were found in 44.3% of null cell tumors, 36.4% of corticotroph tumors, 16.7% of Pit-1 lineage tumors, and 17.3% of gonadotroph tumors. In logistic regression analysis, Pit-1 (OR 5.90, 95% CI 1.71-20.4, P = 0.0050) and null tumors (OR 4.14, 95% CI 1.86-9.23, P = 0.0005) were associated with cavernous sinus invasion. Recurrence was found in 8 (4.9%) patients, but without significant differences between tumor subtypes. The presence of cavernous sinus invasion was correlated with recurrence (HR = 1.95, 95% CI 1.10-3.46, P = 0.0227). CONCLUSION: Among nonfunctioning Pit-NETs, Pit-1 lineage tumors tend to invade the cavernous sinus, corticotroph tumors may produce dura mater defects, and null cell tumors tend to cause both. Pit-NETs with cavernous sinus invasion require a careful attention to recurrence.

Residual diffusion-weighted imaging hyperintense signal in primary central nervous system lymphoma can predict early recurrence.

BACKGROUND: The treatment response of primary central nervous system lymphomas (PCNSLs) is mainly evaluated using postcontrast T1-weighted imaging (T1WI). Because poorly enhanced lesions may contain residual tumors, the combination of evaluation methods will potentially improve the accuracy of determining treatment effectiveness. In this study, we evaluated the usefulness of diffusion-weighted imaging (DWI) in predicting recurrence among patients with PCNSL who achieved complete response (CR)/unconfirmed CR (CRu). METHODS: Fifty-four patients newly diagnosed with PCNSL who were treated at our institution and achieved CR/CRu at the end of treatment were included in this study. The patients were divided into two groups according to the presence or absence of residual DWI hyperintense signal at the tumor site at the end of treatment. Kaplan-Meier analysis was performed to analyze the median overall survival (OS) and progression-free survival (PFS). RESULTS: The mean age of the 54 patients was 66.4 ± 13.3 years. The induction therapies were HD-MTX in 20 patients, R-MPV in 29 patients, and other chemotherapies in five patients. Radiotherapy was performed in 35 patients, high-dose cytarabine therapy in 14 patients, and autologous hematopoietic stem cell transplantation in one patient, and of the 54 patients, 10 had no consolidation therapy. The residual DWI hyperintense signal sign was observed in 18 patients. The R-MPV regimen was statistically associated with a lower rate of residual DWI hyperintense signal (p = 0.0453). The median PFS was statistically shorter in the residual DWI hyperintense signal group than in the non-residual DWI hyperintense signal group (14.0 months vs. 85.1 months) (p < 0.0001, log-rank test). CONCLUSION: A residual DWI hyperintense signal at the end of treatment was statistically associated with shorter PFS. Among patients who achieved CR/CRu evaluated based on postcontrast T1WI, DWI could be a valuable additional sequence to predict the early recurrence of PCNSL.

FOXM1 Promotes Mesothelioma Cell Migration and Invasion via Activation of SMAD Signaling.

BACKGROUND/AIM: Forkhead box M1 (FOXM1) is a transcription factor closely associated with various human malignancies and is considered an attractive target for cancer therapy. Mesothelioma is a malignancy primarily due to asbestos exposure and certain genetic factors, requiring a better understanding of tumorigenesis for improved treatment. Asbestos-exposed human mesothelial cells have been reported to up-regulate FOXM1 expression in a dose-dependent manner. MATERIALS AND METHODS: FOXM1 expression was evaluated in mesothelioma tissues and cell lines. FOXM1 small interfering RNA was transfected into mesothelioma cell lines to analyze its biological functions and regulatory mechanisms. RESULTS: FOXM1 was over-expressed in mesothelioma tissues and cell lines. Knock-down of FOXM1 in mesothelioma cell lines inhibited cell proliferation, migration, and invasion. These results suggest that up-regulation of FOXM1 expression promotes mesothelioma tumorigenesis and progression. We previously reported that insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) promotes the proliferation, migration, and invasion of mesothelioma cell lines. In this study, IGF2BP3 knock-down suppressed FOXM1 expression in mesothelioma cell lines. Our results suggest that IGF2BP3, an upstream regulator, contributes to increased FOXM1 expression. Furthermore, IGF2BP3 and FOXM1 knock-down suppressed SMAD signaling by inhibiting SMAD2/3 phosphorylation in mesothelioma cell lines. CONCLUSION: IGF2BP3/FOXM1 promotes mesothelioma cell migration and invasion via SMAD signaling, highlighting IGF2BP3/FOXM1 as a potential target for mesothelioma treatment.

miR-142-3p Suppresses Invasion and Adhesion of Mesothelioma Cells by Downregulating ITGAV.

INTRODUCTION: Malignant mesothelioma is an aggressive cancer associated with asbestos exposure. Currently, the efficacy of therapeutics is limited in malignant mesothelioma, and developing more effective therapies is the need of the hour. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), have attracted attention as therapeutic targets. To explore potential therapeutic targets, we focused on miR-142-3p expression, which was found to be significantly downregulated in mesothelioma cell lines in our previous study. METHODS: Mesothelioma cell lines and tissues were validated for expression of miR-142-3p or integrin subunit alpha-V (ITGAV). We transfected mesothelioma cell lines with miR-142-3p mimic and ITGAV siRNA and analyzed their biological functions. RESULTS: We found that miR-142-3p was significantly downregulated in mesothelioma tissues. Transfection with miR-142-3p mimic significantly suppressed cell proliferation, migration, and invasion. Bioinformatics analysis of potential targets of miR-142-3p identified ITGAV. Membrane ITGAV expression in mesothelioma cell lines was confirmed using immunocytochemistry. ITGAV was significantly upregulated in mesothelioma tissues. Moreover, transfection of miR-142-3p mimics into mesothelioma cell lines significantly suppressed ITGAV expression, indicating that miR-142-3p targets ITGAV. Next, ITGAV siRNA transfection into mesothelioma cell lines inhibited cell proliferation, migration, and invasion. Further investigation of cell adhesion mechanisms showed that the miR-142-3p/ITGAV axis specifically affects mesothelioma cell adhesion via vitronectin in the extracellular matrix. CONCLUSION: This study proposed that the miR-142-3p/ITGAV axis is involved in tumor progression in malignant mesothelioma.

Epstein-barr Virus Negative Primary Central Nervous System Lymphoma Developed after Treatment of Glioblastoma: A Case Report.

Temozolomide is an oral alkylating agent with moderate side effects compared to other agents. However, the development of secondary malignancies following temozolomide has been reported. We describe the first case of primary central nervous system lymphoma (PCNSL) occurrence following glioblastoma treatment. A 69-year-old male was admitted to our hospital with a chief complaint of headache and dysnomia for six months. A ring-enhanced mass of the left temporal lobe was observed and gross total removal was performed. The tumor was pathologically diagnosed as isocitrate dehydrogenase (IDH)-wildtype glioblastoma and he received 60 Gy of local irradiation in 30 fractions, with concurrent temozolomide at a dose of 75 mg/m2. Grade 2 lymphopenia was discovered during treatment. Within 6 months, the patient developed a right parietal intra-axial tumor without local recurrence and was given 150-200 mg/m2 oral temozolomide for five consecutive days of a 28-day cycle. Within five cycles of temozolomide, complete remission was observed; however, after the eighth cycle, a new lesion in the right temporal lobe was discovered. Surgical removal was performed and histological findings were consistent with diffuse large B-cell lymphoma, and the final diagnosis of Epstein-Barr virus negative PCNSL was established.

Characteristics and therapeutic strategies of radiation-induced glioma: case series and comprehensive literature review.

INTRODUCTION: The so-called radiation-induced glioma (RIG, a secondary glioma after cranial irradiation), is a serious late effect after cranial radiation therapy. The clinical characteristics of and ideal treatment for these tumors are unclear. We analyzed our case series and conducted a comprehensive literature review to reveal the precise characteristics of RIGs. METHODS: We analyzed the cases of six patients with RIGs treated at our institution and 354 patients with RIGs from the literature. The latency period from irradiation to the development of each RIG and the median overall survival of the patients were subjected to Kaplan-Meier analyses. Spearman's correlation test was used to determine the relationship between age at irradiation and the latency period. RESULTS: The mean age of the 360 patients at the development of RIG was 27.42 ± 17.87 years. The mean latency period was 11.35 ± 8.58 years. Multiple gliomas were observed in 28.4%. WHO grade 3 and 4 RIGs accounted for 93.3%. The latency periods were significant shorter in the higher WHO grade group (p = 0.0366) and the concomitant systemic chemotherapy group (p < 0.0001). Age at irradiation was negatively associated with the latency period (r =- 0.2287, p = 0.0219). The patients treated with radiotherapy achieved significantly longer survival compared to those treated without radiotherapy (p = 0.0011). CONCLUSIONS: Development in younger age, multiplicity, and high incidence of grade 3 and 4 are the clinical characteristics of RIGs. Cranial irradiation at older ages and concomitant chemotherapy were associated with shorter latency for the development of RIG. Radiation therapy may be the feasible treatment option despite radiation-induced gliomas.

Downregulation of FTL decreases proliferation of malignant mesothelioma cells by inducing G1 cell cycle arrest.

Pleural malignant mesothelioma is a malignant tumor with a poor prognosis that is strongly associated with asbestos exposure during its development. Because there is no adequate treatment for malignant mesothelioma, investigation of its molecular mechanism is important. The ferritin light chain (FTL) is a subunit of ferritin, and its high expression in malignant tumors, including malignant mesothelioma, has recently been reported; however, its role in malignant mesothelioma is unclear. The purpose of the present study was to clarify the function of FTL in malignant mesothelioma. The expression levels of FTL in malignant mesothelioma were examined using the Cancer Cell Line Encyclopedia database and our previous data. The short interfering (si)RNA against FTL was transfected into two mesothelioma cell lines, ACC-MESO-1 and CRL-5915, and functional analysis was performed. Expression of p21, p27, cyclin-dependent kinase 2 (CDK2) and phosphorylated retinoblastoma protein (pRb) associated with the cell cycle were examined as candidate genes associated with FTL. The expression levels of the FTL mRNA were higher in malignant mesothelioma compared with other tumors in the Cancer Cell Line Encyclopedia database, and among other genes in our previous study. Reverse transcription-quantitative PCR and western blotting demonstrated suppression of FTL expression in two cell lines transfected with FTL siRNA compared with cells transfected with negative control (NC) siRNA. In the two cell lines transfected with FTL siRNA, proliferation was significantly suppressed, and cell cycle arrest was observed in the G1 phase. The levels of p21 and p27 were increased, while those of CDK2 and pRb were decreased compared with NC. However, no significant differences in invasion and migration ability were revealed between FTL siRNA-transfected cells and NC. In conclusion, FTL may increase the proliferative capacity of malignant mesothelioma cells by affecting p21, p27, CDK2 and pRb, and promoting the cell cycle at the G1 phase.

Isolated Neurohypophysial Sarcoidosis Involving the Cavernous Sinus Mimicking a Malignant Tumor.

Because of nonspecific clinical and radiological findings, it is difficult to diagnose isolated neurosarcoidosis without histological examination. Distinguishing neurosarcoidosis from neoplasm, infectious disease, or granulomatous disease can be challenging. In this study, we present a case of a 61-year-old female who presented with unilateral blindness. Magnetic resonance imaging (MRI) revealed a large invasive mass lesion located in the neurohypophysis with homogeneous enhancement after the injection of gadolinium. The lesion involved the bilateral cavernous sinus, which extended along the dura of the skull base with leptomeningeal lesions. Contrast-enhanced computed tomography (CT) and fluorodeoxyglucose positron emission tomography/CT of the entire body showed no other lesions. Biochemical examinations showed no useful data, including angiotensin-converting enzyme, ß-glucan, soluble interleukin-2 receptor, and T-SPOT. Cerebrospinal fluid examination revealed only the elevation of total protein. Under the preoperative diagnosis of a malignant tumor or metastatic tumor, followed by tuberculosis, fungal infection, or granulomatous disease, a biopsy was performed to immediately determine the appropriate therapy, which revealed the histological diagnosis of sarcoidosis. After steroid therapy, the lesions had markedly shrunk as observed on MRI, and the eyesight of the patient's right eye was completely restored. In this case, without a biopsy, discriminating between sarcoidosis and a malignant tumor was difficult. We believe that a prompt histological diagnosis of an invasive isolated neurohypophysial mass lesion involving the bilateral cavernous sinus, which is similar to a malignant tumor, is essential for selecting the appropriate therapy.

Identification of Novel Diagnostic Markers for Malignant Pleural Mesothelioma Using a Reverse Translational Approach Based on a Rare Synchronous Tumor.

Although the routine use of immunohistochemistry has improved the accuracy of histopathologic diagnosis in clinical practice, new methods for discovering novel diagnostic markers are still needed. We sought new diagnostic markers for malignant pleural mesothelioma (MPM) using a reverse translational approach with limited archival tissues from a very rare case. Total RNA extracted from formalin-fixed paraffin-embedded (FFPE) tissues of a synchronous collision tumor consisting of MPM and pulmonary adenocarcinoma (PAC) was employed for gene expression profiling (GEP) analysis. Among the 54 genes selected by GEP analysis, we finally identified the following two candidate MPM marker genes: PHGDH and TRIM29. Immunohistochemical analysis of 48 MM and 20 PAC cases showed that both PHGDH and TRIM29 had sensitivity and specificity almost equivalent to those of calretinin (sensitivity 50% and 46% vs. 63%, and specificity 95% and 100% vs. 100%, respectively). Importantly, of the 23 epithelioid MMs, all 3 calretinin-negative cases were positive for TRIM29. These two markers may be diagnostically useful for immunohistochemical distinction between MPMs and PACs. This successful reverse translational approach based on FFPE samples from one very rare case encourages the further use of such samples for the development of novel diagnostic markers.

Diffusion-weighted imaging-gadolinium enhancement mismatch sign in diffuse midline glioma.

BACKGROUND: Diffuse midline glioma (DMG), H3 K27M-mutant including diffuse intrinsic pontine glioma (DIPG) is a disease with dismal prognosis. We focused on diffusion-weighted imaging (DWI) and gadolinium enhanced T1WI (Gd), especially high intensity on DWI at non-enhanced lesion, i.e. DWI-Gd mismatch sign, to establish as an imaging biomarker of DMG patients. MATERIALS AND METHODS: Our institutional review board approved this retrospective study. Twenty-one patients diagnosed as DMG including DIPG at our institution between 2007 and 2020 were enrolled in this study. All patients underwent local radiotherapy of 54 Gy/30 fractions. We studied the relationship between imaging features including DWI-Gd mismatch sign and prognosis. RESULTS: DWI-Gd mismatch sign was found in 9 out of 21 DMG patients. Among different imaging characteristics, existence of high intensity on DWI (P = 0.0014), gadolinium enhancement (P = 0.00071) were the significant poor prognostic markers in DMG, which were consistent with the previous reports about DIPG. In our results, positive DWI-Gd mismatch sign was statistically strongest poor prognostic imaging biomarker, and patients with positive DWI-Gd mismatch sign had shorter OS compared to those with negative mismatch sign (9.9 months vs 18.6 months, P = 0.00062). DWI/Gd mismatch sign and intratumoral bleeding were more common in DMG at thalamus compared to DMG at pons/DIPG (P = 0.046 and P = 0.0017, respectively). CONCLUSIONS: DWI-Gd mismatch sign may be an imaging biomarker for poor prognosis in DMG. (E-1601).

Intratumoral Hemorrhage After Endoscopic Third Ventriculostomy for Obstructive Hydrocephalus Caused by Brain Tumors.

BACKGROUND: Endoscopic third ventriculostomy (ETV) for obstructive hydrocephalus and endoscopic biopsy (EB) for intraventricular and paraventricular tumors are standard therapies because they are minimally invasive procedures. Although EB-associated hemorrhagic risk has been well documented, there have been only a few reports on hemorrhagic risk associated with ETV. We conducted a single-institution retrospective study on the incidence of hemorrhage secondary to EB and/or ETV. METHODS: We retrospectively reviewed patient characteristics, procedure, pathological findings, and complications including hemorrhage of 100 patients with intraventricular and paraventricular tumors who underwent EB and/or ETV at our institution from 2000 to 2020. RESULTS: EB/ETV combined surgery (combined group), EB-alone surgery (EB-alone group), and ETV-alone surgery (ETV-alone group) were performed in 44 (44%), 24 (24%), and 32 (32%) patients, respectively, and all procedures were successful. The rates of definitive and suggestive diagnoses in EB were 76.5% and 23.5%, respectively. Adverse events were observed in 6 patients. In the combined group, acute obstruction of the ETV stoma was observed in 1 patient and transient double vision was observed in 1 patient. Transient aqueductal stenosis/obstruction was observed in 2 patients in the EB-alone group. In the ETV-alone group, hemorrhage was observed in 2 patients; these patients developed intratumoral hemorrhage despite ETV-alone surgery. Subsequently, these 2 patients underwent tumor removal, and the histopathological diagnosis was atypical teratoid/rhabdoid tumor in both. CONCLUSIONS: For obstructive hydrocephalus with atypical teratoid/rhabdoid tumor, physicians must be aware of the risk of postoperative intratumoral hemorrhage after performing ETV.

Downregulation of lncRNA PVT1 inhibits proliferation and migration of mesothelioma cells by targeting FOXM1.

Malignant mesothelioma is a highly aggressive tumor, and an effective strategy for its treatment is not yet available. Long non­coding RNAs (lncRNAs) have been reported to be associated with various biological processes, including the regulation of gene expression of cancer­related pathways. Among various lncRNAs, plasmacytoma variant translocation 1 (PVT1) acts as a tumor promoter in several human cancers, but its mechanism of action has not yet been elucidated. Increased PVT1 expression was identified in ACC­MESO­1, ACC­MESO­4, CRL­5915, and CRL­5946 mesothelioma cell lines. PVT1 expression was investigated in mesothelioma cell lines by reverse transcription­quantitative polymerase chain reaction and its functional analysis by cell proliferation, cell cycle, cell migration, and cell invasion assays, as well as western blot analysis of downstream target genes. Knockdown of PVT1 expression in these cell lines by small interfering RNA transfection resulted in decreased cell proliferation and migration and increased the proportion of cells in the G2/M phase. The results of reverse transcription­quantitative polymerase chain reaction analysis revealed that PVT1 knockdown in mesothelioma cell lines caused the downregulation of Forkhead box M1 (FOXM1) expression, while the results of western blot analysis revealed that this knockdown reduced FOXM1 expression at the protein level. In addition, combined knockdown of PVT1 and FOXM1 decreased the proliferation of mesothelioma cell lines. In conclusion, PVT1 and FOXM1 were involved in the proliferation of cancer cells. Therefore, PVT1­FOXM1 pathways may be considered as candidate targets for the treatment of malignant mesothelioma.

Glypican-1 is a novel immunohistochemical marker to differentiate poorly differentiated squamous cell carcinoma from solid predominant adenocarcinoma of the lung.

BACKGROUND: The histological classification of non-small cell lung cancer (NSCLC) is essential in determining new cancer-specific targeted therapies. However, the accurate typing of poorly differentiated is difficult, particularly for poorly differentiated squamous cell carcinoma and adenocarcinoma of the lung with limited immunohistochemical markers. Thus, novel immunohistochemical markers are required. We assumed the possibility of the immunohistochemical expression of glypican-1 in lung squamous cell carcinoma. METHODS: The microarray dataset GSE43580 from Gene Expression Omnibus database were analyzed for confirming the gene expression of glypican-1 in lung squamous cell carcinoma. We immunohistochemically investigated the use of glypican-1 as a novel positive diagnostic marker for lung squamous cell carcinoma. Glypican-1 expression in 63 cases of poorly differentiated lung squamous cell carcinoma and 60 cases of solid predominant lung adenocarcinoma was investigated by immunohistochemistry. Additionally, we compared glypican-1 expression with the expressions of p40, cytokeratin 5/6, thyroid transcription factor-1 (TTF-1), and napsin A. RESULTS: All 63 cases of lung squamous cell carcinoma showed glypican-1 expression. In contrast, only 2 cases of lung adenocarcinoma showed glypican-1 expression. The sensitivity, specificity, and diagnostic accuracy of glypican-1 expression for differentiating lung squamous cell carcinoma from lung adenocarcinoma were 100%, 96.7%, and 98.4%, respectively. These were similar to those of p40 and significantly better than those of CK 5/6. CONCLUSIONS: We recommend the use of glypican-1 as an additional positive marker of lung squamous cell carcinoma.

Detecting non-germinomatous germ cell tumor component by arterial spin labeling perfusion-weighted MR imaging in central nervous system germ cell tumor.

PURPOSE: Differentiating between germinoma and non-germinomatous germ cell tumor (NGGCT) is important because sensitivity to chemotherapy and/or radiotherapy is quite different between these two subgroups. In this study, we evaluated whether the arterial spin labeling (ASL) based perfusion-weighted imaging (PWI) could provide additional information for the differential diagnosis between germinoma and NGGCT. METHOD: Between 2011 and 2018, 20 patients with central nervous system (CNS) germ cell tumor (GCT) who underwent preoperative MR imaging including ASL-PWI were enrolled in this study. Relative tumor blood flow (rTBF) was evaluated on ASL-PWI by manually placing regions of interest at gadolinium enhanced part of the tumors and normal subcortical white matter. Presence of intratumoral T1 hyperintense foci and apparent diffusion coefficient (ADC) were also evaluated. The final diagnosis was made by the combination of tumor markers and the histological diagnosis. RESULTS: Among 20 patients of CNS-GCT, 11 were diagnosed as germinoma and 9 were diagnosed as NGGCT. In the germinoma subgroup, the rTBF ranged from 0.90 to 1.71 (mean 1.21, median 1.09), while it ranged from 1.14 to 5.75 (mean 3.91, median 3.31) in NGGCT subgroup. The receiver operating characteristic (ROC) curve showed that calculating rTBF is useful for differentiating between germinoma and NGGCT (area under the curve (AUC) 0.929, P = 0.0012) compared to intratumoral T1 hyperintense foci (AUC 0.788, P = 0.0304) and ADC (AUC 0.919, P = 0.0016). CONCLUSIONS: High rTBF obtained by ASL-PWI implied the presence of NGGCT component. This information might help in deciding the chemotherapy/radiotherapy intensity.

Insulin-Like Growth Factor 2 mRNA Binding Protein 3 Promotes Cell Proliferation of Malignant Mesothelioma Cells by Downregulating p27Kip1.

Malignant mesothelioma is a tumor with a poor prognosis, mainly caused by asbestos exposure and with no adequate treatment yet. To develop future therapeutic targets, we analyzed the microarray dataset GSE 29370 of malignant mesothelioma and reactive mesothelial hyperplasia, downloaded from the Gene Expression Omnibus (GEO) database. We identified insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) as one of the significantly upregulated genes in malignant mesothelioma. IGF2BP3 functions as an oncoprotein in many human cancers; however, to our knowledge, this is the first study on the biological function of IGF2BP3 in malignant mesothelioma cells. The knockdown of IGF2BP3 in malignant mesothelioma cells resulted in the suppression of cell proliferation with an increase in the proportion of cells in the G1 phase of the cell cycle. Furthermore, knockdown of IGF2BP3 inhibited cell migration and invasion. We focused on the cell cycle assay to investigate the role of IGF2BP3 in cell proliferation in malignant mesothelioma. Among the various proteins involved in cell cycle regulation, the expression of p27 Kip1 (p27) increased significantly upon IGF2BP3 knockdown. Next, p27 siRNA was added to suppress the increased expression of p27. The results showed that p27 knockdown attenuated the effects of IGF2BP3 knockdown on cell proliferation and G1 phase arrest. In conclusion, we found that IGF2BP3 promotes cell proliferation, a critical step in tumorigenesis, by suppressing the expression of p27 in malignant mesothelioma.

Metachronous Double Pituitary Adenoma with Altered Transcriptional Factor Profile: A Case Report and Literature Review.

Double pituitary adenomas (DPAs), especially metachronous DPAs, are extremely rare and there has been no report about DPAs with altered transcriptional factors. We describe the case of a 25-year-old man who presented with acromegaly 7 years after surgery for a non-functioning pituitary adenoma (NFPA). Before the initial surgery, endocrine evaluation confirmed NFPA or silent somatotroph pituitary adenoma (SPA) because of normal serum levels of insulin-like growth factor-1 (IGF-1) and insufficient suppression of growth hormone (GH) levels in the oral glucose tolerance test (OGTT). Immunohistochemistry of resected tissue obtained from gross total resection (GTR) with transsphenoidal surgery (TSS) was negative for follicle-stimulating hormone, luteinizing hormone, GH, and Pit-1 but positive for GATA3, which confirmed the gonadotroph pituitary adenoma (GPA) diagnosis. Seven years later, follow-up brain MRI revealed a 13.3 × 5.6 × 4.7 mm tumor within the sellar turcica. The endocrine evaluation confirmed acromegaly because of high serum levels of IGF-1 and insufficient suppression of GH levels upon OGTT. GTR with TSS was again performed, and immunohistochemistry was negative for GATA3 but positive for GH and Pit-1. Surprisingly, he showed altered transcription factor expressions between initial and recurrent surgery. Based on the overall clinical course and hormonal secretion findings, we speculated metachronous development of a DPA, i.e., SPA followed by GPA, wherein a few remaining cells of the SPA might have regrown after the initial surgery. We conducted a literature review of cases that documented altered hormone secretion at recurrence and emphasized the necessity of identifying a small adenoma when there is a discrepancy between pathological findings and hormone secretion tests.

Radiological and Immunostaining Characteristics of H3.3 G34R-Mutant Glioma: A Report of 3 Cases and Review of the Literature.

INTRODUCTION: H3.3 G34R/V mutation is predominantly identified in the supratentorial nonmidline tumors. However, this tumor is not yet categorized as an entity in 2016 WHO CNS classification. More information is necessary to further determine the characteristics of this tumor. CASE PRESENTATION: Three cases of adolescent hemispheric glioma were treated in our institution. All tumors showed the characteristics of huge tumor size with mild peritumoral edema on T2WI/FLAIR, hyperintense on DWI, and slight partial enhancement by gadolinium. The single-voxel proton MR spectroscopy revealed characteristics of high choline peak, marked decrease in N-acetyl aspartate peak, and small lactate peak. The histopathological diagnosis, based on 2007 WHO CNS classification, was high-grade glioma in 2 cases and a PNET. Immuno-staining revealed that the tumor cells were positive against H3.3 G34R, H3K27me3, and p53 antibodies and negative against H3K27M, IDH1-R132H, ATRX, and Olig2 antibodies. Pyrosequencing analysis confirmed H3.3 G34R mutation, IDH-wildtype, and BRAF-wildtype. CONCLUSION: Radiological and immunostaining findings are characteristic in our 3 cases of H3.3 G34-mutant glioma. It is essential to consider H3.3 G34-mutant glioma as a differential diagnosis particularly in pediatric and adolescents and young adult hemispheric tumors.