Regarding this question, multiple studies with solid as well as blood tumors indicated that STAT3 and STAT5 were constitutively activated by tyrosine kinases other than JAK [21,22], and the JAK family protein consisted of four proteins, JAK1, JAK2, JAK3 and tyrosine kinase 2. This evidence concerns the gene JAK2 and hematopoietic and lymphoid system neoplasm.