Subsequent work analyzed the frequency of Brachyury amplifications in 181 sporadic chordoma samples: 7% of the tumors displayed amplification of the Brachyury locus, 39% of the tumors were polysomic for chromosome 6, and 4.5% of primary tumors showed a minor allelic gain of Brachyury [70]. This evidence concerns the gene TBX1 and chordoma.