BCOR and cancer: While minor, these subpopulations contained many additional somatic mutations, including shared mutations in cancer genes including NOTCH1, CCND3, and BCOR. The AB subpopulation showed the highest number of somatic mutations, including point mutations in RPTOR and PIK3C2B and a massive 50-fold amplification in the KRAS oncogene as well as focal homozygous deletions of the EFNA5 and COL4A5 tumor suppressors.