The present invention relates to a method of testing whether a patient suffering of multiple myeloma will respond or not to a DNA methyltransferase inhibitor (DNMTi) comprising: i. determining the expression level (ELi) of several genes G1-Gn selected from table A in a biological sample obtained from said patient ii. comparing the expression level (ELi) determined at step i) with a predetermined reference level (ELRi) iii. calculating the DMS score trough the following formula (I) wherein &bgr1 represent the regression &bgr coefficient reference value for the gene Gi and Ci=1 if the expression of the gene Gi (ELi) is higher than the predetermined reference level (ELRi) or Ci=&minus1 if the expression of the gene (ELi) is lower than or equal to the predetermined reference level (ELRi) comparing the score DMS determined at step iii) with a predetermined reference value DMSR and concluding that the patient will respond to the DNMTi when the DMS score is higher than the predetermined reference value DMSR or concluding that the patient will not respond to the DNMTi when the DMS score is lower than the predetermined reference value DMSR. DMS = &sum i = 1 n &bgr i × Ci ( I )
