Abstract B35: BMP regulation of cancer stem cell quiescence is responsible for chemotherapeutic resistance in glioblastoma

Introduction: Cancer stem cells (CSCs) represent a distinct cellular population that has been implicated in tumor recurrence following chemotherapy. Accumulating evidence indicates that BMP signaling plays an important role in the regulation of CSCs, and may be involved in the resistance of CSCs to cytotoxic drugs. The role of BMP pathway regulation of the CSC phenotype responsible for treatment resistance in glioblastoma (GBM) has not been explored.

Methods: Paraffin-embedded (FFPE) samples from GBM patients were used to evaluate the expression of markers for BMP signaling (pSMAD1/5/8), proliferation (PCNA), and stemness (SOX2) by immunostaining. We tested the self-renewal capacity of primary patient-derived glioma stem cell (GSC) lines using a sphere formation assay. Expression of stemness markers SOX2 and Bmi-1 in BMP4 treated and untreated GSCs, was analyzed by Western blotting. We also performed xenograft transplantation, whereby GSCs were injected intracranially into immunedeficient mice. When tumor formation was confirmed post-injection, mice were administrated EdU and sacrificed at successive time points thereafter. The frequency of all EdU positive cells as well as ID-1positive/ EdU positive cells was quantified from the primary tumor sections throughout the labeling and chase. To study chemoresistance in glioblastoma, GSC lines were treated with graded concentrations of temozolomide (TMZ).

Results: We found that pSMAD1/5/8 positive cells in primary patient tumors were largely PCNA-negative. BMP4 treatment inhibited GSC proliferation and self-renewal (sphere-formation), but did not abolish expression of markers of stemness, such as Sox2 and Bmi-1, or tumorigenicity. In our in vivo model, we found ID-1 positive cells retain EdU following a long-term chase. Taken together, these results demonstrate that BMP4-enriched cells possess the characteristics of a quiescent stem cell population. BMP4 treatment protects GSCs against TMZ-induced growth inhibition. Furthermore, pSMAD1/5/8-expressing cells do not possess the DNA damage marker gamma-H2AX following TMZ treatment, suggesting that activation of the BMP pathway protects GSCs against TMZ-induced DNA damage.

Conclusion: This study establishes that the BMP signaling pathway is involved in the maintenance of GSC quiescence and may play a role in glioblastoma chemoresistance.

Citation Format: Megan YiJun Wu, Angela Celebre, Jeffrey Chan, Jennifer Guan, Karan Dhand, James Loukides, Jason Karamchandani, Sunit Das. BMP regulation of cancer stem cell quiescence is responsible for chemotherapeutic resistance in glioblastoma. [abstract]. In: Proceedings of the AACR Special Conference: Advances in Brain Cancer Research; May 27-30, 2015; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2015;75(23 Suppl):Abstract nr B35.

Abstract A34: Id-1 mediates glioma stem cell chemoresistance to temozolomide

Introduction: Id-1 (inhibitor of differentiation and DNA binding) is a transcriptional regulator involved in stem cell maintenance. It has previously been shown to regulate self-renewal and confer chemoresistance in colon cancer stem cells. Id-1 has not been studied within the context of glioblastoma (GBM). We hypothesized that Id-1 mediates glioma stem cell (GSC) survival in response to chemotherapy and subsequently promotes tumour recurrence.

Methods: To study the role of Id-1 in response to chemotherapy in vitro, three GSC lines were treated with the chemotherapy agent, temozolomide (TMZ), for seven days. Immunoblot and comparative QT-PCR were used to measure Id-1 protein and mRNA expression post-TMZ, respectively. To evaluate Id-1 expression in patient samples, we constructed a tissue microarray (TMA), which included 77 tissue specimens from patients diagnosed with GBM. Detailed clinical information was available for all of the selected samples, including survival times, treatment regimens, and primary versus recurrent tumor status. Immunohistochemistry was performed on the TMA and Id-1 protein expression was subsequently quantified using Panoramic Image Analysis Software Platform. Id-1 expression was correlated to survival outcome, along with other clinically relevant variables. We also employed a bioinformatics approach, exploring survival data from The Cancer Genome Atlas (TCGA) database that were based on Id-1 expression for patients diagnosed with GBM.

Results: Id-1 expression in GSCs strongly increased in response to increasing doses of TMZ in vitro (0 uM, 25 uM, 100 uM). In patient tumor samples (n=77), Id-1 expression did not correlate with survival. However, among the recurrent patients who received chemotherapy after primary tumor resection (n=6), patients with increased Id-1 expression post-chemotherapy had a shorter latency to recurrence compared to patients with decreased Id-1 expression post-chemotherapy. Finally, the TCGA data corroborated our TMA patient data, finding comparable overall survival trends between patients with high versus low Id-1 expression.

Conclusion: These findings demonstrate that Id-1 levels increase in response to chemotherapy, suggesting its potential role in chemoresistance. Since resistance to chemotherapeutic drugs is one of the major reasons for treatment failure in glioblastoma, Id-1 inactivation may serve as a novel strategy for enhancing therapy and improving outcomes in patients with the disease.

Citation Format: Angela Celebre, Megan YiJun Wu, Marc Remke, Michael Taylor, Jason Karamchandani, Sunit Das. Id-1 mediates glioma stem cell chemoresistance to temozolomide. [abstract]. In: Proceedings of the AACR Special Conference: Advances in Brain Cancer Research; May 27-30, 2015; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2015;75(23 Suppl):Abstract nr A34.

Mammographic microcalcifications and breast cancer tumorigenesis: a radiologic-pathologic analysis

BACKGROUND

Microcalcifications (MCs) are tiny deposits of calcium in breast soft tissue. Approximately 30% of early invasive breast cancers have fine, granular MCs detectable on mammography; however, their significance in breast tumorigenesis is controversial. This study had two objectives: (1) to find associations between mammographic MCs and tumor pathology, and (2) to compare the diagnostic value of mammograms and breast biopsies in identifying malignant MCs.

METHODS

A retrospective chart review was performed for 937 women treated for breast cancer during 2000-2012 at St. Michael's Hospital. Demographic information (age and menopausal status), tumor pathology (size, histology, grade, nodal status and lymphovascular invasion), hormonal status (ER and PR), HER-2 over-expression and presence of MCs were collected. Chi-square tests were performed for categorical variables and t-tests were performed for continuous variables. All p-values less than 0.05 were considered statistically significant.

RESULTS

A total of 937 patient charts were included. About 38.3% of the patients presented with mammographic MCs on routine mammographic screening. Patients were more likely to have MCs if they were HER-2 positive (52.9%; p < 0.001). There was a significant association between MCs and peri-menopausal status with a mean age of 50 (64%; p = 0.012). Patients with invasive ductal carcinomas (40.9%; p = 0.001) were more likely to present with MCs than were patients with other tumor histologies. Patients with a heterogeneous breast density (p = 0.031) and multifocal breast disease (p = 0.044) were more likely to have MCs on mammograms. There was a positive correlation between MCs and tumor grade (p = 0.057), with grade III tumors presenting with the most MCs (41.3%). A total of 52.2% of MCs were missed on mammograms which were visible on pathology (p < 0.001).

CONCLUSION

This is the largest study suggesting the appearance of MCs on mammograms is strongly associated with HER-2 over-expression, invasive ductal carcinomas, peri-menopausal status, heterogeneous breast density and multifocal disease.

IDH mutation in glioma: new insights and promises for the future

IMPORTANCE

Over the past 4 years, our understanding of gliomagenesis and the practice of neuro-oncology have been radically changed by the discovery of mutations involving the isocitrate dehydrogenase (IDH) enzymes. IDH mutation has been found to be an inciting event in gliomagenesis and to have a profound effect on the molecular and genetic route of oncogenic progression and on clinical outcome.

OBJECTIVES

To review the role of IDH enzymes in normal physiology and describe aberrations in the IDH pathway that are associated with gliomagenesis, to review recent work examining the effect of IDH-targeted therapy in cancers harboring IDH mutation, and to determine how this work has expanded our understanding of the role of IDH in the development and progression of glioma.

EVIDENCE REVIEW

A systematic review of the literature dating from 2008, when IDH mutation was discovered to be clinically significant in glioma, to 2013 was performed using the PubMed database. The following search terms were used: IDH, IDH1, IDH2, and isocitrate dehydrogenase, in conjunction with glioma or leukemia. The search was limited to articles published in English. Further hand searching was performed using a review of the pertinent references from the identified publications. All identified original articles were investigated for content and critiqued by Z.T. and S.D.

FINDINGS

IDH mutation is an early event in gliomagenesis and has significant implications for glioma progression and tumor behavior. Early evidence suggests that IDH may be a therapeutic target in IDH-mutant gliomas.

CONCLUSIONS AND RELEVANCE

IDH mutation is a central and defining event in the development and progression of glioma and may be a key target for future therapies for these types of neoplasms.

Metastatic ovarian carcinoma to the brain: an approach to identification and classification for neuropathologists

Brain metastasis is an uncommon but increasing manifestation of ovarian epithelial carcinoma and neuropathologists' collective experience with these tumors is limited. We present clinicopathological characteristics of 13 cases of brain metastases from ovarian epithelial carcinoma diagnosed at two academic institutions. The mean ages at diagnosis of the ovarian carcinoma and their subsequent brain metastases were 58.7 and 62.8 years, respectively. At the time of initial diagnosis of ovarian carcinoma the majority of patients had an advanced stage and none had brain metastases as their first manifestation of malignancy. Brain metastases tended to be multiple with ring-enhancing features on neuroimaging. Primary tumors and their brain metastases were all high-grade histologically and the histologic subtypes were: nine high-grade serous carcinoma (HGSC) cases, two clear cell carcinoma (CCC) cases and a single case each of carcinosarcoma and high-grade adenocarcinoma. A recommended histo- and immunopathological approach to these tumours are provided to aid neuropathologists in the recognition and classification of metastatic ovarian carcinoma to the brain.

Ectopic prolactin-producing pituitary adenoma in a benign ovarian cystic teratoma

We report the presence of pituitary tissue in a benign ovarian cystic teratoma removed surgically from a 43-year-old woman. The pituitary consisted of non-tumorous neurohypophysis and adenohypophysis containing mainly prolactin (PRL)-immunopositive cells (80 % of cells) and a small PRL-producing adenoma. The ultrastructure of the tumor cells differed significantly from PRL cells in the non-tumorous and adenomatous intrasellar pituitary. It appears that cells differing in ultrastructure from intrasellar pituitary PRL cells can also produce PRL.

Convergence of NF-κB-mediated inflammatory and HNF4α-mediated metabolic signaling networks in age-related thymic involution (HEM4P.229)

Thymic epithelial cell loss results in age-related thymic involution and immune deficiency. We investigated mechanisms of TEC loss during chronological aging (6 weeks, 7 months, 15 months) of normal C57BL6/J mice. Aged TEC showed replicative senescence with increased apoptosis, decreased proliferation, decreased telomerase activity and shortened telomere length. A subpopulation of aged TEC expressed Fas in response to pro-inflammatory cytokines (TNFα,IL-1β) made by aged thymocytes. Fas signaling and caspase-8 activation were induced by FasL selectively expressed by aged intrathymic memory T cells. Combined pharmacological inhibition of Caspase-8 and TEC growth stimulation by KGF restored thymopoiesis to neonatal levels. Aged TEC differentially expressed a 175-gene set predicted to be dually regulated by two transcription factors, NF-κB and HNF4α, which are activated by inflammatory cytokines and fatty acids, respectively. NF-κB and HNF4α signaling in aged TEC was confirmed by ChIP assays demonstrating binding to promoters of age-related genes, gene reporter assays, and synergistic induction of TEC apoptosis by inflammatory cytokines and fatty acids. TEC aging is mediated by the convergence of different TFs responsive to inflammatory and metabolic signals on shared promoters. Thymic regeneration in aging will require mitigation of the effects of non-autonomous inflammatory and metabolic signals, e.g., from infection and obesity, which drive TEC death and thymic involution.

Mouse models of glioblastoma: lessons learned and questions to be answered

Glioblastoma is the most common primary brain tumour in adults. While many patients achieve disease remission following treatment with surgical resection, radiation therapy and chemotherapy, this remission is brief and invariably followed by tumour recurrence and progression. Recent work using mouse models of the disease, coupled with data generated by The Cancer Genome Atlas, have given us new insights into the mechanisms that underlie gliomagenesis and result in glioblastoma heterogeneity. These findings suggest that the treatment of glioblastoma will require a more nuanced understanding of their biology and the employment of targeted therapeutic approaches. In this review, we will summarize the current state of mouse modeling in glioma, with a focus on how these models may inform our understanding of this disease and its treatment.

Inhibition of CXCR7 extends survival following irradiation of brain tumours in mice and rats

Background:

In experimental models of glioblastoma multiforme (GBM), irradiation (IR) induces local expression of the chemokine CXCL12/SDF-1, which promotes tumour recurrence. The role of CXCR7, the high-affinity receptor for CXCL12, in the tumour's response to IR has not been addressed.

Methods:

We tested CXCR7 inhibitors for their effects on tumour growth and/or animal survival post IR in three rodent GBM models. We used immunohistochemistry to determine where CXCR7 protein is expressed in the tumours and in human GBM samples. We used neurosphere formation assays with human GBM xenografts to determine whether CXCR7 is required for cancer stem cell (CSC) activity in vitro.

Results:

CXCR7 was detected on tumour cells and/or tumour-associated vasculature in the rodent models and in human GBM. In human GBM, CXCR7 expression increased with glioma grade and was spatially associated with CXCL12 and CXCL11/I-TAC. In the rodent GBM models, pharmacological inhibition of CXCR7 post IR caused tumour regression, blocked tumour recurrence, and/or substantially prolonged survival. CXCR7 expression levels on human GBM xenograft cells correlated with neurosphere-forming activity, and a CXCR7 inhibitor blocked sphere formation by sorted CSCs.

Conclusions:

These results indicate that CXCR7 inhibitors could block GBM tumour recurrence after IR, perhaps by interfering with CSCs.

Flexible Omnidirectional Carbon Dioxide Laser as an Effective Tool for Resection of Brainstem, Supratentorial, and Intramedullary Cavernous Malformations

BACKGROUND:

Lasers have a long history in neurosurgery, yet bulky designs and difficult ergonomics limit their use. With its ease of manipulation and multiple applications, the OmniGuide CO2 laser has reintroduced laser technology to the microsurgical resection of brain and spine lesions. This laser, delivered through a hollow-core fiber lined with a unidirectional mirror, minimizes energy loss and allows precise targeting.

OBJECTIVE:

To analyze resections performed by the senior author from April 2009 to March 2013 of 58 cavernous malformations (CMs) in the brain and spine with the use of the OmniGuide CO2 laser, to reflect on lessons learned from laser use in eloquent areas, and to share data on comparisons of laser power calibration and histopathology.

METHODS:

Data were collected from electronic medical records, radiology reports, operative room records, OmniGuide CO2 laser case logs, and pathology records.

RESULTS:

Of 58 CMs, approximately 50% were in the brainstem (30) and the rest were in supratentorial (26) and intramedullary spinal locations (2). Fifty-seven, ranging from 5 to 45 mm, were resected, with a subtotal resection in 1. Laser power ranged from 2 to 10 W. Pathology specimens showed minimal thermal damage compared with traditionally resected specimens with bipolar coagulation.

CONCLUSION:

The OmniGuide CO2 laser is safe and has excellent precision for the resection of supratentorial, brainstem, and spinal intramedullary CMs. No laser-associated complications occurred, and very low energy was used to dissect malformations from their surrounding hemosiderin-stained parenchymas. The authors recommend its use for deep-seated and critically located CMs, along with traditional tools.

Preclinical efficacy of the anti-hepatocyte growth factor antibody ficlatuzumab in a mouse brain orthotopic glioma model evaluated by bioluminescence, PET, and MRI

PURPOSE

Ficlatuzumab is a novel therapeutic agent targeting the hepatocyte growth factor (HGF)/c-MET pathway. We summarize extensive preclinical work using this agent in a mouse brain orthotopic model of glioblastoma.

EXPERIMENTAL DESIGN

Sequential experiments were done using eight- to nine-week-old nude mice injected with 3 × 10(5) U87 MG (glioblastoma) cells into the brain. Evaluation of ficlatuzumab dose response for this brain tumor model and comparison of its response to ficlatuzumab and to temozolamide were conducted first. Subsequently, various small-animal imaging modalities, including bioluminescence imaging (BLI), positron emission tomography (PET), and MRI, were used with a U87 MG-Luc 2 stable cell line, with and without the use of ficlatuzumab, to evaluate the ability to noninvasively assess tumor growth and response to therapy. ANOVA was conducted to evaluate for significant differences in the response.

RESULTS

There was a survival benefit with ficlatuzumab alone or in combination with temozolamide. BLI was more sensitive than PET in detecting tumor cells. Fluoro-D-thymidine (FLT) PET provided a better signal-to-background ratio than 2[(18)F]fluoro-2-deoxy-d-glucose (FDG) PET. In addition, both BLI and FLT PET showed significant changes over time in the control group as well as with response to therapy. MRI does not disclose any time-dependent change. Also, the MRI results showed a temporal delay in comparison to the BLI and FLT PET findings, showing similar results one drug cycle later.

CONCLUSIONS

Targeting the HGF/c-MET pathway with the novel agent ficlatuzumab appears promising for the treatment of glioblastoma. Various clinically applicable imaging modalities including FLT, PET, and MRI provide reliable ways of assessing tumor growth and response to therapy. Given the clinical applicability of these findings, future studies on patients with glioblastoma may be appropriate.

Highly proliferative sellar chordoma with unusually rapid recurrence

Chordomas are tumors of notochordal differentiation of low to intermediate grade malignancy. These tumors are typically slow growing, with an indolent but progressive clinical course. We present a case of a highly proliferative chordoma arising in a 73-year-old woman with unusually rapid clinical growth and aggressive histologic and immunohistochemical features. This patient had an unusually brief preclinical course and within 1 month of developing headaches presented to medical attention with diplopia. The resected chordoma showed uncommonly elevated mitotic activity, without the histologic hallmarks of de-differentiation. This proliferative activity correlated with elevated Ki67 staining (60%), B-cell leukemia/lymphoma1 (BCL1) expression (100%), and topoisomerase IIα staining (>95%). E-cadherin expression was also lost throughout the majority of the tumor. Other markers of epithelial mesenchymal transition (EMT) including vimentin, N-cadherin, Slug and Twist, were also strongly expressed in this aggressive tumor. The sellar component of the tumor recurred within a 2-month interval. The evaluation of the additional biomarkers, including makers of EMT studied in this, case may allow for identification of aggressive chordomas in which the tempo of disease is significantly more rapid than in typical cases of chordoma.

Expression of CXCR7, CXCR4, CXCR3 and their chemokine ligands in glioblastoma

2043

Background: The chemokine receptors CXCR4 and CXCR7, and their shared ligand CXCL12/SDF-1, have been implicated in multiple aspects of tumorigenesis, including tumor cell proliferation, angiogenesis, vasculogenesis, and metastasis. Recently, a role for CXCR4 and CXCR7 has been postulated in the control of glioblastoma growth and vasculogenesis. We set out to define the expression patterns of these proteins on primary glioblastoma tumors and associated vasculature. Methods: First, a tumor microarray containing grades 1, 3, and 4 glioma samples were analyzed by immunohistochemical techniques for the expression of CXCR7. Second, two glioblastoma microarrays were analyzed by the same technique for CXCR7, CXCR4, and their shared chemokine ligand CXCL12. The same microarrays were also probed for the expression of the additional CXCR7 ligand, CXCL11/ITAC, as well as the chemokine receptor CXCR3, which is also a receptor for CXCL11. Tissues were scored in a blinded fashion by a certified neuropathologist for both the intensity of signal and location of signal for all proteins tested. Results: CXCR7 expression was largely dependent on tumor grade, as the receptor was usually absent on most grade 1 gliomas but was moderately-to-highly expressed in the majority of anaplastic astrocytomas and glioblastomas. CXCR7 expression on tumor-associated vasculature was seen in all samples and its expression level also increased with glioma grade. In contrast to CXCR7, CXCR4 expression in glioblastoma was usually limited to the glioma cells, with only infrequent expression on the vasculature. Conversely, CXCL12 expression in glioblastoma was usually limited to the vasculature. CXCR3 was detected in a subset of glioblastomas, and only on the glioma cells. The CXCR7 and CXCR3 ligand CXCL11 was, like CXCR7, expressed on both the glioma cells and vasculature. Conclusions: These results, in light of prior evidence for CXCR7 in tumor growth, suggest a positive role for CXCR7 in the development of glioblastoma. Because CXCR7 colocalizes with its ligands, CXCL12 and CXCL11, as well as their other receptors, CXCR4 and CXCR3, the function of CXCR7 in glioblastoma may lie in the regulation of both the CXCR4/CXCL12 and CXCR3/CXCL11 axes.

Extravascular Papillary Endothelial Hyperplasia Mimicking Neoplasm After Radiosurgery

BACKGROUND AND IMPORTANCE:

Papillary endothelial hyperplasia (PEH) is a rare form of exuberant reactive endothelial proliferation that can mimic neoplasm. We report the largest series of patients with histologically confirmed intracranial extravascular PEH developing in the field of previous treatment with stereotactic radiosurgery.

CLINICAL PRESENTATION:

We collected the clinical, radiological, surgical, and pathological findings from 4 patients in whom intracranial extravascular PEH developed after treatment with stereotactic radiosurgery. In all patients, the development of an enlarging hemorrhagic mass lesion at the site of previous radiotherapy on magnetic resonance imaging was radiographically suspicious for neoplasm and prompted biopsy or resection. All 4 patients elected to undergo biopsy or surgical resection. Histological examination of the biopsy and resection specimens in all patients demonstrated the classic features of PEH.

CONCLUSION:

The interval to the development of PEH ranged from 5 months to 6 years, 10 months. Clinical follow-up was available for 3 of the 4 patients. None of these 3 patients have demonstrated evidence of recurrence during a mean follow-up period of 22 months (range, 15–30 months). These patients share common radiological features, potentially allowing preoperative diagnosis and improved guidance of clinical management. These cases suggest a link between radiosurgery and the development of PEH. These findings also suggest that PEH should be considered in the differential diagnosis for patients treated with radiosurgery in whom a hemorrhagic mass lesion subsequently develops at or near the site of previous treatment. We think that complete surgical excision is the best treatment for intracranial PEH.

Specificity of brachyury in the distinction of chordoma from clear cell renal cell carcinoma and germ cell tumors: a study of 305 cases

Brachyury is recognized as a specific marker for notochord-derived tissues and neoplasms, and has become a defining immunohistochemical feature of chordoma. The main differential diagnostic consideration for chordoma is chondrosarcoma, which is known to lack brachyury expression. However, within the spectrum of genitourinary neoplasia, metastatic germ cell tumors and clear cell renal cell carcinoma may also be close morphological mimics of chordoma, particularly given the increasing prevalence of small tissue samples from image-guided biopsies. Although immunoreactivity for brachyury has been reported in a few germ cell tumors, a thorough characterization of staining by specific subtype has not been performed in a large series. Additionally, brachyury expression in clear cell renal cell carcinoma has not been well studied. In this study, immunohistochemical expression with the brachyury antibody was evaluated in 111 germ cell tumors, 30 non-neoplastic and neoplastic (non-germ cell) testicular tissues, and 184 metastatic clear cell renal cell carcinomas using tissue microarray technology. In addition, immunoreactivity for PAX-8 and SALL-4 was evaluated in 12 chordomas on whole section. No nuclear brachyury expression was identified in any of the 101 germ cell tumors within the tissue microarray (including choriocarcinoma (1), embryonal carcinoma (20), intratubular germ cell neoplasia unclassified (2), seminoma (64), spermatocytic seminoma (1), teratoma (5) and yolk sac tumor (8)), in any of the 30 non-neoplastic and neoplastic (non-germ cell) testicular tissues, or in any of the 10 whole-section seminomas. All 184 metastatic clear cell renal cell carcinomas were also non-reactive for brachyury. All 12 chordomas showed strong nuclear immunoreactivity for brachyury, but no expression of SALL-4. In all, 1 of 12 chordoma cases showed patchy, 1+ nuclear immunoreactivity for PAX-8. This study confirms the specificity of brachyury for chordoma in the differential diagnostic distinction from the potential genitourinary mimics, germ cell tumors and metastatic clear cell renal cell carcinoma.

End-stage cardiac disease as an initial presentation of systemic myopathies: case series and literature review

Life-threatening cardiomyopathy is associated with certain systemic myopathies and usually presents as an end-stage progression of the disease. However, cardiac symptoms can sometimes precede muscle weakness. The authors reviewed medical records from 2003 to 2008 on patients attending their neuromuscular clinic and identified patients who initially presented with an end-stage cardiomyopathy and were later diagnosed with a specific muscle disease through muscle biopsy. They report 5 cases of children who initially presented with cardiomyopathies without neuromuscular symptoms. The cardiac symptoms were so severe that 4 of them required cardiac transplantation and 1 died prior to transplantation. Review of muscle pathology confirmed the diagnoses of Becker muscular dystrophy, myofibrillar myopathy, mitochondrial myopathy with cytochrome oxidase deficiency, Danon disease, and glycogen storage disease. The authors conclude that cardiomyopathy can be the initial presentation of a wide spectrum of systemic myopathies. Careful evaluation of neuromuscular systems should be carried out in patients presenting with end-stage cardiomyopathies.

Langerhans cell histiocytosis in a 5-month-old presenting with biparietal masses

Langerhans cell histiocytosis (LCH) is a rare proliferative disorder that occurs most commonly in the pediatric population as a result of pathological clonal proliferation of Langerhans cells with subsequent damage and destruction to surrounding tissue. Clinically, LCH presents in a variety of ways, which often results in prolonged time to diagnosis and subsequently poorer outcomes. In this case report, the authors describe an unusually early presentation of multisystem LCH in a patient at birth, which resulted in a 5-month delay to diagnosis and treatment. This patient presented both atypically young and with an uncommon initial manifestation of multisystem disease with multiple soft-tissue swellings rather than early skin involvement. Additionally, this patient had an unusual radiographic appearance with biparietal skull destruction on initial skull radiographs and biparietal soft-tissue lesions on CT resembling cephalohematoma at 3 months of age. The clinical and radiological evaluation, pathology, and treatment strategies are discussed, with particular attention paid to the importance of further workup of atypical nonresolving cephalohematomas to prevent disease progression and poorer outcomes.

Pineal parenchymal tumor of intermediate differentiation: clinicopathological report and analysis of epidermal growth factor receptor variant III expression

OBJECTIVE

Epidermal growth factor receptor (EGF) receptor gene amplification is commonly seen in cancer and is the target of many therapies. EGF receptor variant III (EGFRvIII) is the most common variant of the EGF receptor and has been detected in a large percentage of patients with glioblastoma multiforme but not in normal brain. Therapies targeting EGFRvIII are currently being investigated in clinical and preclinical trials.

METHODS

A 14-year-old girl who presented with headaches was found to have a pineal parenchymal tumor of intermediate differentiation. We review the histopathological properties that led to the diagnosis of this tumor. EGF receptor gene amplification and EGFRvIII expression have not been analyzed in pineal tumors. We investigated EGF receptor gene status and EGFRvIII expression in this patient's tumor.

RESULTS

Tumor tissue was obtained and analyzed with flow cytometry, reverse-transcriptase polymerase chain reaction, and Western blot analysis. EGFRvIII was detected by all 3 methods. The tumor was further analyzed by fluorescence in situ hybridization, which did not reveal EGF receptor gene amplification.

CONCLUSION

This is the first report of EGFRvIII expression in a pineal tumor. It is interesting that this variant is detected in the absence of EGF receptor gene amplification. A larger study evaluating the presence of EGFRvIII in pineal tumors is needed.

Melanin concentrating hormone is a novel regulator of islet function and growth

Melanin concentrating hormone (MCH) is a hypothalamic neuropeptide known to play a critical role in energy balance. We have previously reported that overexpression of MCH is associated with mild obesity. In addition, mice have substantial hyperinsulinemia and islet hyperplasia that is out of proportion with their degree of obesity. In this study, we further explored the role of MCH in the endocrine pancreas. Both MCH and MCHR1 are expressed in mouse and human islets and in clonal beta-cell lines as assessed using quantitative real-time PCR and immunohistochemistry. Mice lacking MCH (MCH-KO) on either a C57Bl/6 or 129Sv genetic background showed a significant reduction in beta-cell mass and complemented our earlier observation of increased beta-cell mass in MCH-overexpressing mice. Furthermore, the compensatory islet hyperplasia secondary to a high-fat diet, which was evident in wild-type controls, was attenuated in MCH-KO. Interestingly, MCH enhanced insulin secretion in human and mouse islets and rodent beta-cell lines in a dose-dependent manner. Real-time PCR analyses of islet RNA derived from MCH-KO revealed altered expression of islet-enriched genes such as glucagon, forkhead homeobox A2, hepatocyte nuclear factor (HNF)4alpha, and HNF1alpha. Together, these data provide novel evidence for an autocrine role for MCH in the regulation of beta-cell mass dynamics and in islet secretory function and suggest that MCH is part of a hypothalamic-islet (pancreatic) axis.

Altered islet homeostasis before classic insulitis in BB rats

Young diabetes-prone BioBreeding (BBdp) rats fed a diabetes-promoting, cereal-based, NIH-07 (NIH) diet have decreased islet area compared with rats fed a diabetes-retardant diet at a time when classic insulitis is minimal. This finding raised the possibility that islet homeostasis in BBdp rats may be abnormal. To investigate this possibility further, comparisons were made between BBdp and BB control (BBc) rats fed a diabetes-promoting NIH diet for 22 days after weaning. Pancreatic sections were fixed in Bouin's solution and evaluated using immunohistochemistry and image analysis by staining with antibodies for islet hormones: insulin, glucagon; cell proliferation markers: PCNA, BrdU; markers of islet neogenesis: PDX-1, cytokeratin 20; apoptosis was assessed by morphological changes and TUNEL staining. Body weight of BBdp rats was significantly smaller than BBc rats. Although the total number of islets was higher in BBdp compared with BBc, both islet and beta-cell fraction were similar. BBdp rats had a lower beta-cell mass than BBc rats, although this was not statistically significant. Alpha-cell fraction and beta-cell size were similar. Apoptotic bodies were rare in beta-cells but more frequent in acinar tissue of BBdp rats. When the day-night cycle was reversed to synchronize the apoptotic process, the number of apoptotic bodies in islets and in acinar cells was increased. Apoptotic bodies and BrdU+ or PCNA+ beta-cells were more frequently encountered in islets of BBdp rats. Although the frequency of CK20+ islets in BBdp rats was not different, CK20+ area fraction was smaller in BBdp. The number of extra-islet insulin+ and glucagon+ clusters (<4 cells) was significantly greater in BBdp rats. These data are consistent with an enhanced compensatory or "repair" process in the pancreas of BBdp rats that attempts to maintain islet cell mass by altering homeostasis through increased islet neogenesis.