Whereas high Id4 expression is reported in B-cell acute lymphoblastic leukemia [25] and B-cell precursor acute lymphoblastic leukemia (BCP-ALL) [26] due to the t(6;14)(p22;q32) chromosomal translocation, and in bladder [27] and rat mammary gland carcinomas [28] suggests that it may also have pro-tumor activity. Here, ID4 is linked to neoplasm.