The IC50 of DC44SMe for Ramos, Namalwa and HL60 / s cancer cells was 2.0 nM, 2.8 nM and 1.9 nM, respectively. DC44SMe can be used for targeted treatment of cancer. DC44SMe is a phosphate prodrug of DC44 and can be used in the synthesis of antibody-drug conjugates (ADC).