While we and others have shown that the presence of CK1α is absolutely required for pyrvinium to exert its anti-cancer effects on HCT-116 colon carcinoma cells [17], we also demonstrated that CK1α depletion is insufficient to rescue the growth of CML and AML cell lines exposed to pyrvinium (Figure 3a–3d and Supplemental Figure S3). This evidence concerns the gene CSNK1A1 and chronic myelogenous leukemia, BCR-ABL1 positive.