Biallelic inactivation of PBRM1 as a molecular driver in a rare pineoblastoma case: illustrative case

BACKGROUND: Pineoblastomas are a rare and aggressive pediatric neuroectodermal tumor subtype. Because of their rarity, pineoblastomas are still poorly understood, and there is little research delineating their molecular development and underlying genetic phenotype. Recent multiomic studies in pineoblastomas and pineal parenchymal tumors identified four clinically and biologically relevant consensus groups driven by signaling/processing pathways; however, molecular level alterations leading to these pathway changes are yet to be discovered, hence the importance of individually profiling every case of this rare tumor type. OBSERVATIONS: The authors present the comprehensive somatic genomic profiling of a patient with pineoblastoma presenting with the loss of protein polybromo-1 (PBRM1) as a candidate genomic driver. Loss of PBRM1, a tumor suppressor, has been reported as a driver event in various cancer types, including renal cell carcinoma, bladder carcinoma, and meningiomas with papillary features. LESSONS: This is the first report presenting biallelic loss of PBRM1 as a candidate molecular driver in relation to pineoblastoma.