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 The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.