Leukaemic cells carrying TEL/AML1 fusion gene are more sensitive to treatment with L-asparaginase compared to other subtypes of ALL.     ///    Significantly higher expression of AsnS was found in untreated leukaemic cells from children with TEL/AML1[+] ALL (n=20) in comparison with the group of age-matched children with ALL bearing no known fusion gene (n=25.     ///    Upregulation of asparagine synthetase fails to avert cell cycle arrest induced by L-asparaginase in TEL/AML1-positive leukaemic cells..     ///    "Interestingly, none of the TEL/AML1[+] patients with high AsnS level relapsed, whereas 10/15 patients with AsnS below median relapsed (P=0.00028). "    ///    "We hypothesise that TEL/AML1[+] cells are unable to progress into the S phase of cell cycle under nutrition stress caused by L-asparaginase, despite the ability of AsnS upregulation. "    ///    "Therefore, high AsnS levels in TEL/AML1[+] patients correlate with better prognosis, possibly reflecting the stretched metabolic demand of the lymphoblast.. "    ///    Cell cycle analysis revealed TEL/AML1[+] cells to accumulate in G1/G0 phase (81-98%) compared to TEL/AML1[-] cells (47-60%).     ///    Quantitative analysis of asparagine synthetase (AsnS) expression showed the ability of TEL/AML1[+] cells to increase AsnS mRNA levels after L-asparaginase treatment to the same extent as TEL/AML1[-] leukaemic and nonleukaemic lymphoid cells.     ///    We demonstrate in vitro the prolonged growth suppression of TEL/AML1[+] cells compared to TEL/AML1[-] leukaemic cells after L-asparaginase treatment simulating treatment protocol. 