To summarise the information, despite target engagement, the bosutinib-VHL PROTAC was unable to degrade either c-ABL or BCR-ABL in K562 CML cells, potentially due to the insufficient orientation of the VHL ligase for efficient ubiquitination of BCR-ABL. The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.