measured the expression of CDK12 in tumor tissue in a cohort of 56 spine chordoma patients using immunohistochemistry, and grouped chordomas as those with low CDK-12 expression (less than 75% of the cells with positive nuclear staining) and those with high CDK-12 expression (more than 75% of the cells with positive nuclear staining) (52). This evidence concerns the gene CDK12 and chordoma.