MKI67 and chordoma: Zenonos et al. prospectively evaluated 105 clival chordoma samples with fluorescence in situ hybridization (FISH) of chromosomal loci 1p36 and 9p21 as well as immunohistochemistry for Ki-67 in the interest of identifying molecular markers for prognosis, finding that 1p36 deletions and 9p21 homozygous deletions were predictive of poorer progression-free survival after surgery or radiotherapy, independent of Ki-67 [111].