TP53 and neoplasm: Other recent research into the genetic interaction between MYC or MYCN and p53 has utilized non-natively arising orthotopic tumor implantation models in which either cerebellar granule precursor cells or cerebellar stem cells (CD133+Lin-) were exogenously transduced with either MYC or MYCN and were re-implanted orthotopically into mice [47,48].