TSC1 and chordoma: However, our finding that AKT is activated in over 90% of chordomas argues that the tumour suppressor genes, TSC2 and TSC1, in sporadic chordoma are likely to be ‘inactivated’ not as a result of loss of heterozygosity but rather by phosphorylation of TSC2, at threonine 1462, by p-AKT (Inoki et al, 2002).