Abstract: Objective : To investigate the changes of lymphocytes respectively expressing FasL,GzB and Pf in axillary lymph node of breast cancer after in situ treatment with high intensity focused ultrasound (HIFU). Methods : Expression of FasL, GzB and Pf of lymphocytes in axillary lymph node were detected by SP immunohistochemical stain. Results : In HIFU group, the number of positive lympho-cytes of FasL, GzB and Pf in mestastasis-positive and negative axillary lymph node was obviously higher than these of control group respectively (P<0.01). Conclusions : The positive lymphocytes of FasL,GzB and Pf in TDLN (whether it had metastasis or not) was significantly increased after HIFU treatment for primary breast cancer., which could cause the enhancement of local antitumor cytotoxicity and pr-vent tumor from metastasis.