This decrease in Ki67+ cells was similar to that observed for adult OPCs in the spinal cord when Ascl1 was conditionally deleted (Kelenis, Hart, Edwards‐Fligner, Johnson, & Vue, 2018) and supports the interpretation that the increased survival of Ascl1CKO tumor mice may result from a decrease in the rate of tumor cell proliferation. Here, ASCL1 is linked to neoplasm.