NF1 and glioma: Utilizing a mouse model of primary gliomas that originate from adult oligodendrocyte precursor cells (OPCs) with conditional knockout of the tumor suppressor genes Trp53 and Nf1 (referred to as the CKO model), researchers have observed a high incidence of gliomas in the olfactory bulb, the initial site of olfactory sensory neuron transmission.