PSMB9 and cancer: Furthermore the genetic approach has already revealed that somatic mutations in the LMP2 molecule or its enhancer region correlate to the initiation of several cancer progressions and other disorders (Heward et al. 1999; Satoh et al. 2006; Krämer et al. 2007; Liu et al. 2007; Mehta et al. 2007), 35.7% (5/14) of uterine LMS tissues had somatic mutations in the Lmp2 promoter region, which is required for transcriptional activation.