Abstract: Objective To evaluate the expression and correlation of Rab5A and CD44v9 in breast cancer tissues.Methods The expression of Rab5A and CD44v9 in 53 cases of breast cancer tissues and 21 cases of benign breast disease tissues was detected by immunohistochemistry S-P method.Results The expressions of Rab5A and CD44v9 were obviously stronger in breast cancer tissues than that in benign breast disease tissues(P＜0.05);the expression of Rab5A and CD44v9 were obviously stronger in lymph node-positive cases than that in negative cases(P＜0.05),and were correlated with lymph-node status.With the two proteins expressed at higher levels,the probability of node-positive cases was enhanced(P＜0.05).Moreover,the expressions of the two proteins were positive correlation to TNM stage(P＜0.05).In addition,the expressions of the two proteins were positive correlation to each other,the higher levels of either protein was expressed at the higher levels of the other(P＜0.05).Conclusions Rab5A and CD44v9 proteins may play a synergetic role in breast cancer genesis,growth,invasion and metastasis.It is indicated that the united detection of the two proteins may offer important clinical significance for breast cancer early diagnosis and prognosis.