Browsing by Author "Pham, Robin"
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Item Genomic Profiling of Pediatric Tumors: A Single Institution Experience(2020) Pham, Robin; Hamby, Tyler; Ray, Anish; Swilling, AubreyPurpose The goal of this project is to study the prevalence of potentially actionable oncogenic variants in a sample of pediatric tumors, to identify agents that may target those variants, and to highlight the potential utility of targeted therapies in pediatric cancers. This study will also describe the tumor mutation burden (TMB), microsatellite instability (MSI), and programmed death-ligand 1 (PD-L1) status of the included samples. Methods Retrospective chart review was conducted on 82 patients treated for cancer who underwent molecular sequencing from 2013 to 2019 at Cook Children's Medical Center. Tumor samples were sent to Foundation Medicine, Inc. for sequencing, which identified genetic variants and available approved or experimental targeted therapies. When requested, reports included TMB, MSI, and PD-L1 status. Results There were 5 patients with central nervous system tumors, 4 patients with leukemia and lymphoma, 33 patients with neuroblastoma, and 40 patients with other solid tumors. Thirty-five (43%) patients were identified as having actionable genetic alterations, and 13 (16%) patients received targeted therapy. Thirty-four patients were tested for PD-L1 status and 6 (18%) were positive. TMB was determined for 51 patients: 44 (86%) were low burden, 7 (14%) intermediate burden, and none were high burden. MSI status was determined for 41 patients and all were MSI-stable. Conclusion Whole genome sequencing has emerged as a tool to identify driver genetic alterations in various tumors. This study highlights how tumor profiling can be utilized to identify potential molecular targets and biomarkers in pediatric cancers.Item Two Tumors in One: Mixed Malignant Germ Cell Tumor with Rhabdomyosarcomatous Malignant Transformation in a Pediatric Patient(2018-03-14) Margraf, Linda; Ray, Anish; Pham, RobinBackground Testicular germ cell tumors (GCT) are the most common malignancy in males aged 15-34. The transformation of GCTs into secondary somatic-type malignancies is rare, and the lack of clear treatment guidelines presents a clinical challenge for treating physicians especially when chemosensitivities do not overlap. This report will focus on one case of a mixed malignant GCT with a secondary somatic-type malignancy. We highlight our experience in diagnosing and treating this tumor, and through literature review suggest treatment guidelines for treating a pediatric patient with similar tumor presentation. Case Information We report a 15-year-old male previously in good health who complained of a painless hard mass involving his right testicle following surgical repair of bilateral varicocele. A right radical orchiectomy was performed, and surgical resection was achieved with negative margins. Histopathological examination of the mass showed a mixed non-seminomatous malignant GCT with an embryonal rhabdomyosarcoma component that made up more than half of the primary tumor. Our greatest challenge in treating this tumor was understanding how to target the disparate components. The two major components of the tumor were staged and treated separately. The GCT component was deemed low risk, and following surgery, active surveillance strategies were utilized. The rhabdomyosarcoma component, also characterized as low risk, was targeted with chemotherapy in a 24 week therapy schedule with 4 cycles of vincristine, dactinomycin, and cyclophosphamide followed by 4 cycles of vincristine and dactinomycin. The patient completed therapy without complications. 34 months post therapy he remains in good health and has shown no evidence of tumor recurrence. Conclusion Cases such as these remain challenging given the lack of consensus in treating two malignancies whose chemosensitivities do not overlap. There is little debate that successful surgical resection aimed towards securing negative margin remains key in adequate treatment of those with localized disease. With regard to choice of chemotherapy postoperatively, there is some suggestion that malignant transformation of GCT responds poorly to cisplatin based therapy. In treating a pediatric patient with similar tumor presentation, we suggest that choice of chemotherapy agents should be influenced by the transformed histological element as the transformed element may not be responsive to cisplatin-based therapy.