BCOR and cancer: A notable aspect of these findings is that non-coding splice-altering mutations lie in several cancer-associated genes, such as ATRX, BCOR, CDKN2B, MAP3K1, MAP3K4, MDM2, SMAD4, STK11, and TP53. For instance, two proximal G > A intronic mutations result in a new 130-bp exon in STK11, which is associated with lower gene expression.