The most common non-canonical pathway activators include, among others, the cytoplasmic non-receptor tyrosine kinases SRC and ABL (or BCR–ABL fusion proteins in Philadelphia chromosome (Ph+) leukemias), the platelet-derived growth factor receptor (PDGFR) and epidermal growth factor receptor (EGFR) [41,44,45]. This evidence concerns the gene ABL1 and leukemia.