Asparagine is produced by the enzyme asparagine synthetase, encoded by the ASNS gene, which catalyzes the transfer of an amino group to aspartic acid to form asparagine, and may thus counteract the effect of asparaginase and produce resistance as suggested by in vitro experiments conducted in leukemia cell lines and patient lymphoblasts[5,10,18]. This evidence concerns the gene ASPG and leukemia.