Provided herein, in some embodiments, are methods for detecting a level of asparaginase (ASNS) in a sample obtained from a subject having or at risk for stomach cancer or liver cancer, and methods of treating the subject.

Method of in vitro measurement of the presence of factors that are able to neutralize asparaginase activity in a sample of blood, plasma, serum or derived medium that may contain asparaginase neutralizing factors, obtained from a patient, comprising mixing of said sample with asparaginase, incubation of said mixture, then measurement of the residual asparaginase activity in the mixture and determination or quantification of the presence of said neutralizing factors. Method for predicting the efficacy of a treatment with asparaginase.