Faculty Bibliography

Identifying modifiers of glioma risk in patients with type I neurofibromatosis (NF1) could help support personalized tumor surveillance, advance understanding of gliomagenesis, and potentially identify novel therapeutic targets. Here, we report genetic polymorphisms in the human adenylate cyclase gene adenylate cyclase 8 (ADCY8) that correlate with glioma risk in NF1 in a sex-specific manner, elevating risk in females while reducing risk in males. This finding extends earlier evidence of a role for cAMP in gliomagenesis based on results in a genetically engineered mouse model (Nf1 GEM). Thus, sexually dimorphic cAMP signaling might render males and females differentially sensitive to variation in cAMP levels. Using male and female Nf1 GEM, we found significant sex differences exist in cAMP regulation and in the growth-promoting effects of cAMP suppression. Overall, our results establish a sex-specific role for cAMP regulation in human gliomagenesis, specifically identifying ADCY8 as a modifier of glioma risk in NF1. Cancer Res; 75(1); 16-21. (c)2014 AACR.

SUMMARY The following is a general overview of the management of CNS germinomas. Over the last 35 years, CNS germinomas have become one of the pediatric brain tumors with the best outcomes with a greater than 85% overall survival over 5 years. This is in part due to the fact that germinomas are very responsive to chemotherapy and radiation. Some of the major challenges going forward will be to find ways to minimize the adverse effects of our treatments particularly with regard to radiation and to improve the quality of life of patients who develop neurologic, neurocognitive and/or endocrine deficiencies.

Objectives: To evaluate patterns of relapse and outcome in patients newly-diagnosed with CNS 'secreting' (or Mixed Malignant) GCT treated initially with chemotherapy without irradiation on the International CNS GCT Study III. Methods: A retrospective chart review was conducted using all 25 patients enrolled on the International CNS GCT Study III, with at least 7 years follow-up for all patients. Details of the chemotherapy regimen have been published previously (DaSilva et al: Pediatric Blood & Cancer, 54:337-383, 2010). Results: Thirteen patients at diagnosis had 'secreting' CNS GCT by pathology and tumor markers (n=11) or tumor markers alone (n=2). Twelve were treated with chemotherapy alone, one receiving focal irradiation following chemotherapy prior to relapse. Six patients (46%) relapsed (mean of 30.5 months; range 6 to 59 months), two beyond and 4 within the primary site alone. Three patients relapsed 'early' (between 6 and 23 months from diagnosis), 2 with alpha-fetoprotein (AFP) elevations and one without tumor markers assessed; all 3 expired of progressive disease at 2-10 months following initial relapse. Three patients relapsed 'late' (between 37 and 59 months), all without AFP elevations, one with pathologically-pure germinoma, two with mild beta-human chorionic gonadotropin elevations (<20mIU/mL in serum/cerebro-spinal fluid); these patients survive disease-free at 86+, 94+ and 126+ months following additional chemotherapy and irradiation. Conclusions: Patients with CNS 'secreting' tumors who relapse following chemotherapyonly regimens display two distinct patterns of recurrence and outcome; patients relapsing 'early' appear to possess 'secreting' elements and have a dismal prognosis, while patients relapsing 'late' appear to do so with pure germinomatous elements and have an excellent outcome. Current international cooperative group studies utilizing more localized fields of irradiation should evaluate closely the patterns of relapse and outcome; late recurrences with germinomatou!

Recent therapeutic successes have renewed interest in drug combinations, but experimental screening approaches are costly and often identify only small numbers of synergistic combinations. The DREAM consortium launched an open challenge to foster the development of in silico methods to computationally rank 91 compound pairs, from the most synergistic to the most antagonistic, based on gene-expression profiles of human B cells treated with individual compounds at multiple time points and concentrations. Using scoring metrics based on experimental dose-response curves, we assessed 32 methods (31 community-generated approaches and SynGen), four of which performed significantly better than random guessing. We highlight similarities between the methods. Although the accuracy of predictions was not optimal, we find that computational prediction of compound-pair activity is possible, and that community challenges can be useful to advance the field of in silico compound-synergy prediction.

BACKGROUND: The prognosis of diffuse intrinsic pontine glioma (DIPG) remains poor, with no drug proven to be effective. METHODS: Patients with clinically and radiologically confirmed, centrally reviewed DIPG, who had failed standard first-line therapy were eligible for this multicenter phase II trial. The anti-epidermal growth factor receptor (EGFR) antibody, nimotuzumab (150 mg/m(2)), was administered intravenously once weekly from weeks 1 to 7 and once every 2 weeks from weeks 8 to 18. Response evaluation was based on clinical and MRI assessments. Patients with partial response (PR) or stable disease (SD) were allowed to continue nimotuzumab. RESULTS: Forty-four patients received at least one dose of nimotuzumab (male/female, 20/24; median age, 6.0 years; range, 3.0-17.0 years). All had received prior radiotherapy. Treatment was well tolerated. Eighteen children experienced serious adverse events (SAEs). The majority of SAEs were associated with disease progression. Nineteen patients completed 8 weeks (W8) of treatment: There were 2 PRs, 6 SDs, and 11 progressions. Five patients completed 18 weeks (W18) of treatment: 1 of 2 patients with PR at W8 remained in PR at W18, and 3 of 6 children with SD at W8 maintained SD at W18. Time to progression following initiation of nimotuzumab for the 4 patients with SD or better at W18 was 119, 157, 182 and 335 days, respectively. Median survival time was 3.2 months. Two patients lived 663 and 481 days from the start of nimotuzumab. CONCLUSIONS: Modest activity of nimotuzumab in DIPG, which has been shown previously, was confirmed: A small subset of DIPG patients appeared to benefit from anti-EGFR antibody treatment.

BACKGROUND: Activation of the RAS-RAF-MEK-ERK signaling pathway is thought to be the key driver of pediatric low-grade astrocytoma (PLGA) growth. Sorafenib is a multikinase inhibitor targeting BRAF, VEGFR, PDGFR, and c-kit. This multicenter phase II study was conducted to determine the response rate to sorafenib in patients with recurrent or progressive PLGA. METHODS: Key eligibility criteria included age >/=2 years, progressive PLGA evaluable on MRI, and at least one prior chemotherapy treatment. Sorafenib was administered twice daily at 200 mg/m2/dose (maximum of 400 mg/dose) in continuous 28-day cycles. MRI, including 3-dimensional volumetric tumor analysis, was performed every 12 weeks. BRAF molecular testing was performed on tumor tissue when available. RESULTS: Eleven patients, including 3 with neurofibromatosis type 1 (NF1), were evaluable for response; 5 tested positive for BRAF duplication. Nine patients (82%) came off trial due to radiological tumor progression after 2 or 3 cycles, including 3 patients with confirmed BRAF duplication. Median time to progression was 2.8 months (95% CI, 2.1-31.0 months). Enrollment was terminated early due to this rapid and unexpectedly high progression rate. Tumor tissue obtained from 4 patients after termination of the study showed viable pilocytic or pilomyxoid astrocytoma. CONCLUSIONS: Sorafenib produced unexpected and unprecedented acceleration of tumor growth in children with PLGA, irrespective of NF1 or tumor BRAF status. In vitro studies with sorafenib indicate that this effect is likely related to paradoxical ERK activation. Close monitoring for early tumor progression should be included in trials of novel agents that modulate signal transduction.

In order to improve outcomes for CNS mixed malignant germ cell tumors (MMGCT) we sought to increase complete responses (CR) to initial therapy, through intensifying neoadjuvant chemotherapy (CHT1) with added ifosfamide, encouraging second-look surgery, and administering dose-intensive, stem cell-supported chemotherapy (CHT2) to patients with residual tumor, all prior to radiation therapy (RT). Diagnosis was confirmed by biopsy or elevated germ cell tumor markers. After tumor staging was completed, patients received four cycles of chemotherapy (cisplatin, etoposide and ifosfamide, "CHT1"). In patients with

PMID: 24700239

ISSN: 0167-594x

CID: 1037262