Knowing that it is possible to change the configuration of azo‐PROTAC with UV‐C light (changing from a trans (15A) to a cis‐configuration (15B)) (Figure 5), it was observed that in live CML cells treated with PROTAC 4C‐trans, that irradiation with UV‐C radiation caused an increase in BCR‐ABL protein levels.88 This evidence concerns the gene BCR and chronic myelogenous leukemia, BCR-ABL1 positive.