RB1 and cancer: NOTCH1(U50 = 40%, O50 = 9.6%; p = 0.004), RB1(U50 = 20%, O50 = 1.3%; p = 0.045), ASXL1(U50 = 33.4%, O50 = 5.7%; p = 0.003) and IGF2R(U50 = 26.7%, O50 = 8.3%; p = 0.045), which have been reported to be associated with various cancers as tumor suppressors 19-22, showed high frequencies of mutations in younger patients (U50).