Faculty Bibliography

BACKGROUND/UNASSIGNED:Central nervous system (CNS) cancer is the 10th leading cause of cancer-associated deaths for adults, but the leading cause in pediatric patients and young adults. The variety and complexity of histologic subtypes can lead to diagnostic errors. DNA methylation is an epigenetic modification that provides a tumor type-specific signature that can be used for diagnosis. METHODS/UNASSIGNED:We performed a prospective study using DNA methylation analysis as a primary diagnostic method for 1921 brain tumors. All tumors received a pathology diagnosis and profiling by whole genome DNA methylation, followed by next-generation DNA and RNA sequencing. Results were stratified by concordance between DNA methylation and histopathology, establishing diagnostic utility. RESULTS/UNASSIGNED:Of the 1602 cases with a World Health Organization histologic diagnosis, DNA methylation identified a diagnostic mismatch in 225 cases (14%), 78 cases (5%) did not classify with any class, and in an additional 110 (7%) cases DNA methylation confirmed the diagnosis and provided prognostic information. Of 319 cases carrying 195 different descriptive histologic diagnoses, DNA methylation provided a definitive diagnosis in 273 (86%) cases, separated them into 55 methylation classes, and changed the grading in 58 (18%) cases. CONCLUSIONS/UNASSIGNED:DNA methylation analysis is a robust method to diagnose primary CNS tumors, improving diagnostic accuracy, decreasing diagnostic errors and inconclusive diagnoses, and providing prognostic subclassification. This study provides a framework for inclusion of DNA methylation profiling as a primary molecular diagnostic test into professional guidelines for CNS tumors. The benefits include increased diagnostic accuracy, improved patient management, and refinements in clinical trial design.

BACKGROUND: While most meningiomas are considered benign tumors, a subset of these tumors are characterized by a more aggressive clinical course and require multimodal treatment. Beyond surgical and radiotherapeutic options, there are no effective medical treatments available. Somatostatin receptor 2 (SSTR2) is expressed by the majority of meningiomas. 177Lu-DOTATATE is a SSTR2-targeting radionuclide that has been successful in neuroendocrine tumors. Here we report the results of the interim analysis of an ongoing clinical trial (NCT03971461) that is evaluating the effect of 177Lu-DOTATATE in treating progressive intracranial meningiomas.
METHOD(S): In this Simon two-stage design phase II study, adults with advanced intracranial meningiomas received 177Lu-DOTATATE 7.4 GBq (200 mCi) every eight weeks for four doses. 68Ga-DOTATATE PET-MRI was performed before and at the end of treatment. The primary endpoint was progression-free survival at 6 months (PFS-6). Correlative studies evaluated the association of PFS-6, objective response rate, progression-free survival, overall survival with radiographic tumor measurements, 68Ga-DOTATATE uptake on PET-MRI, SSTR2 expression in tumor, and meningioma methylation subclass.
RESULT(S): Fourteen patients (F = 11, M = 3) with progressive meningiomas (WHO I = 3, II = 10, III = 1) have been enrolled. Median age was 63.1 (range 49-78) years. All patients previously underwent tumor resection and at least one course of radiation. Treatment with 177Lu-DOTATATE was well tolerated, no treatment-limiting toxicities were observed. Six of 14 patients (42%) achieved PFS-6. Radiographically, all six patients had achieved Stable Disease. A functional alteration of tumoral SSTR2 expression by 68Ga-DOTATATE PET-MR imaging was observed in three patients.
CONCLUSION(S): Treatment with SSTR2- targeting 177Lu-DOTATATE is well tolerated. In this interim analysis, six of 14 patients achieved PFS-6. This exceeds the predefined threshold to continue to stage two of this study. This clinical trial is now open to patient enrollment at two study sites in the US

Diffuse spinal cord gliomas (SCGs) are rare tumors associated with a high morbidity and mortality that affect both pediatric and adult populations. In this retrospective study, we sought to characterize the clinical, pathological, and molecular features of diffuse SCG in 22 patients with histological and molecular analyses. The median age of our cohort was 23.64 years (range 1-82) and the overall median survival was 397 days. K27M mutation was significantly more prevalent in males compared to females. Gross total resection and chemotherapy were associated with improved survival, compared to biopsy and no chemotherapy. While there was no association between tumor grade, K27M status (p = 0.366) or radiation (p = 0.772), and survival, males showed a trend toward shorter survival. K27M mutant tumors showed increased chromosomal instability and a distinct DNA methylation signature.

OBJECTIVE:Silent corticotroph adenomas (SCAs) behave more aggressively than other non-functioning adenomas (NFAs). This study aims to expand the body of knowledge of the behavior of SCAs. METHODS:Retrospective analysis of 196 non-corticotroph NFAs and 20 SCAs from 2012-2017 was completed. Demographics, clinical presentation, imaging and biochemical data were gathered. The primary endpoint was to identify features of SCAs vs. other NFAs that suggest aggressive disease, including pre-surgical comorbidities, postoperative complications, extent of tumor and recurrence. GRASP MRI images were obtained from a subset of SCAs and NFAs. Permeability data was obtained to compare signal-to-time curve variation between the two groups. RESULTS:With multivariate regression analysis, SCAs showed higher rates of hemorrhage on preoperative imaging than NFAs (p=0.017). SCAs presented more frequently with headache, vision changes and fatigue (p=0.012, p=0.041, p=0.028). SCAs exhibited greater extent of tumor burden with increased occurrence of stalk deviation, suprasellar invasion, optic chiasm compression and cavernous sinus invasion (p=0.008, p=0.021, p=0.022, p=0.015). On GRASP imaging, SCAs had significantly lower permeability of contrast than NFAs (p=0.001). 30% of SCAs were noted to recur with a 14% recurrence rate in other NFAs, though this difference was not of statistical significance (p=0.220). CONCLUSIONS:SCAs exhibit features of more aggressive disease. Interestingly, a significant increase in recurrence was not seen despite these features. The results of this study support the growing body of evidence that SCAs behave more aggressively than other NFPAs and was able to provide some insight into factors that may contribute to recurrence.

The prognostic value of mutations in G-protein genes GNAQ and GNA11 in patients with intracranial and orbital melanocytomas is unknown. The authors present a case of GNA11 mutation (GNA11Q209L) in a 32-year-old male suffering from a meningeal melanocytoma with orbital involvement and ipsilateral Nevus of Ota. The patient underwent gamma knife stereotactic radiosurgery without biopsy and later partial transcranial resection of the melanocytic tumor that was subject to immunohistochemical and molecular analysis. A 50-gene next-generation sequencing panel revealed a 626A>T mutation in the GNA11 gene. One year later, intracranial extension of the melanocytoma necessitated a ventriculoperitoneal shunt and immunotherapy. Future work is needed to determine how GNA11 mutations in melanocytomas influence prognosis and monitoring strategies.

OBJECTIVE:Pituitary carcinoma is a rare tumor, defined as a tumor of adenohypophyseal cells with systemic or craniospinal metastasis. We present a case of a growth hormone (GH)-secreting pituitary carcinoma with a review of literature to better characterize this disease. DESIGN:Case report and literature review of 25 cases of GH-secreting pituitary carcinomas RESULTS: The age of diagnosis of GH-secreting carcinomas ranged 24-69 years old with a mean age of 44.4 with 52% of cases present in females. Mean latency period between diagnosis of acromegaly and transition to pituitary carcinoma was 11.4 years with mean survival being 3.4 years. CONCLUSION:Growth hormone (GH)-secreting pituitary carcinomas are rare and hard to distinguish from aggressive pituitary adenomas. From review of literature, treatment options include debulking surgery, radiotherapy, or chemotherapy with dismal outcomes. There are no diagnostic markers or features which can predict metastatic progression of these tumors. Future studies with genomic landscapes and relevant tumor markers are needed to identify pituitary tumors most likely to metastasize.

Inhibition of mTORC1 signaling has been shown to diminish growth of meningiomas and schwannomas in preclinical studies, and clinical data suggest that everolimus, an orally administered mTORC1 inhibitor, may slow tumor progression in a subset of NF2 patients with vestibular schwannoma (VS). To assess the pharmacokinetics, pharmacodynamics and potential mechanisms of treatment resistance, we performed a pre-surgical (phase 0) clinical trial of everolimus in patients undergoing elective surgery for VS or meningiomas. Eligible patients with meningioma or VS requiring tumor resection enrolled on study received everolimus 10 mg daily for 10 days immediately prior to surgery. Everolimus blood levels were determined immediately prior to and after surgery. Tumor samples were collected intraoperatively. Ten patients completed protocol therapy. Median pre- and post-operative blood levels of everolimus were found to be in a high therapeutic range (17.4 ng/ml and 9.4 ng/ml, respectively). Median tumor tissue drug concentration determined by mass spectrometry was 24.3 pg/mg (range 9.2-169.2). We observed only partial inhibition of phospho-S6 in the treated tumors, indicating incomplete target inhibition compared to control tissues from untreated patients (p=0.025). Everolimus led to incomplete inhibition of mTORC1 and downstream signaling. These data may explain the limited anti-tumor effect of everolimus observed in clinical studies for NF2 patients and will inform the design of future pre-clinical and clinical studies targeting mTORC1 in meningiomas and schwannomas.