We reasoned that this discrepancy might simply reflect the lower tumor size of ATRX-deficient xenografts, and indeed by immunohistochemistry, we found higher levels of CD45 and F4/80 cell labeling in both Atrx KO-A and KO-B tumors than in CRISPR controls (Fig. 4b; Supplementary Fig. 7a, b). This evidence concerns the gene ATRX and neoplasm.