ASNS and acute lymphoblastic leukemia: Interestingly, two genes that are normally expressed at low levels in WT DN3 and even less in DN4 cells were upregulated in both DN3 and DN4 Opa1-deficient T cells: Cox6a2 coding for a respiratory chain subunit that stabilizes dimers of complex IV [36]; and Asparagine synthetase (Asns), coding for the enzyme that synthetizes asparagine from aspartate [37] and a relapse gene in early T cell precursor acute lymphoblastic leukemia [38].