ATOH1 and brain neoplasm: To address whether KIF20A might be similarly crucial for maintaining the proliferation of brain tumor-initiating cells, we crossed the Kif20afl/fl floxed mice with Atoh1-CreER; Ptcfl/fl mice to generate a strain of compound mice carrying the Atoh1-CreER; Ptcfl/fl; Kif20afl/fl alleles.