CD19 and lymphoma: Here, we constructed an anti-CD19-N-(4-carboxycyclohexylmethyl) maleimide N-hydroxysuccinimide ester (SMCC)-protamine (CSP)-STAT3 small interfering RNA (siRNA) conjugate and demonstrated that the CSP-STAT3 siRNA conjugate could specifically bind to normal B cells and A20 lymphoma cells in vitro.