ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Of the VHL-binding conjugates synthesised with varying linker group lengths, DAS-6-2-2-6-VHL (Figure 5A) showed degradation of the wild-type protein Abelson tyrosine kinase (c-ABL) at 1 μM in K562 human CML cells over 24 h.