However, despite the genetic evidence, we are far from understanding the role of CREBBP in tumorigenesis considering relatively low incidence of lymphoid neoplasia in Rubinstein-Taybi syndrome that is caused by CREBBP gene germline defects, and animal models of CREBBP loss that demonstrate hematologic abnormalities but not leukemia [63]. This evidence concerns the gene CREBBP and Rubinstein-Taybi syndrome.