RAF1 and B-cell chronic lymphocytic leukemia: Of note, RAS/RAF mutation frequency was much lower in other cytogenetic defined groups, with up to 16% incidence found among IGHV UM patients bearing tri12 plus other cytogenetic aberrations, mostly del13q but also del11q and del17p, and only 4% incidence detected in patients with del13q as sole chromosomal aberration, highlighting how the type of genomic structural variants strongly influenced RAS/RAF mutation incidence in CLL.