GPR161 and neoplasm: Remarkably, five of six patients with MB demonstrated an inactivation of GPR161 as a result of cnLOH of 1q and in one tumor a focal approximate 425-kb deletion spanned all exons of GPR161. Recurrent cnLOH of 1q so far has not been reported in the MB literature and we therefore assessed the overall frequency of 1q cnLOH events among pediatric patients with MBSHH and its association with GPR161 mutation status (Fig 2B).