FLT3 and hematologic disorder: A number of PROTACs have been developed to target various POIs that are involved in the tumorigenesis and progression of hematologic malignancies, such as anaplastic lymphoma kinase (ALK) [5], Bcl-xL [4], BCR-ABL [6], Bruton’s tyrosine kinase (BTK) [7], BRD4 [8], CDK-6 [9], FMS-like tyrosine kinase-3 (FLT-3) [10], HDAC6 [11], and signal transducer and activator of transcription 3 (STAT3) [3].