The number of targets for the PROTACs, mainly in the cancer area, over the last few years, has increased dramatically; in general, most targets include overexpressed oncogenic proteins [12], for example, nuclear receptors (ER [28], AR [28], retinoic acid receptor alpha (RARα) [46]), protein kinases (protein kinase B (PKB) [47], BCR-abl [48], bruton’s tyrosine kinase (BTK) [49], cyclin dependent kinase 6 (CDK6) [50]), transcriptional regulators (bromodomain containing 4 (BRD4) [51]), and cellular metabolic enzymes (MetAP-2 [17]), just to name a few among many others. Here, BTK is linked to cancer.