AIM: To study the effect of Bene Jones protein (BJP) from multiple myeloma(MM) patient and TGF-?  1 on cultured renal proximal tubular cell(PTC) proliferation. METHODS:[  3H] TdR incorporation was used to study the effect of ?BJP and TGF-?  1 on cultured rat NRK.52E PTC proliferation,the expression of TGF-?  1 in the supernatant of PTC cultured with BJP was assessed with ELISA. RESULTS:① [  3H] TdR incorporation of PTC was inhibited by BJP in a dose-dependent manner,when co-cultured with 100-800 ?mol/L BJP and 2.0 ?g/L TGF-?  1,  the [  3H] TdR incorporation was lower than that of BJP alone, especially  when  BJP≥400 ?mol/L; ②The expression of TGF-?  1 in the supernatant of  PTC cultured with BJP was increased ,especially when BJP≥400 ?mol/L(  P