RESUMEN
Objective To investigate the effect of neoadjuvant chemotherapy on the proportion of G0-G1 phase cells and the expressions of ATP-binding cassette sub-family G member 2 (ABCG2)and CD44 +CD24 -/low in breast cancer patients.Methods Sixty untreated cases with breast invasive ductal carcinoma from May 201 3 to March 201 4 were chosen.All patients were tested by core needle biopsy and pathological diagno-sis,then treated by neoadjuvant chemotherapy.The proportion of G0-G1 phase cells and the contents of ABCG2 and CD44 +CD24 -/low before and after therapy were compared.Results After chemotherapy,the contents of ABCG2 and CD44 +CD24 -/low were (25.1 0 ±1 .50)% and (36.40 ±3.80)/1 05 ,and the proportion of G0-G1 phase cells was (70.50 ±1 .50)%,which were higher than those before treatment [(1 5.88 ±1 .22)%, (25.00 ±3.40)/1 05 ,(60.65 ±1 .30)%](t =8.685,P <0.05;t =9.226,P <0.05;t =8.898,P <0.05).All patients completed four courses of chemotherapy,and the cCR rate,cPR rate,SD rate were respec-tively 1 8.3% (1 1 /60),73.3% (44 /60),8.3%(5 /60).Conclusion Cell cycle can be arrested and the proportion of stem cells can be raised after neoadjuvant chemotherapy which has exact curative effect and clini-cal popularization value.