Establishment of lymph node metastasis of MDA-MB-231 breast cancer model in nude mice

Abstract

To establish lymph node metastasis of breast cancer model in nude mices using MDA-MB-231 cell lines or tumor masses. Divided twelve female nude mices of five weeks into A, B groups randomly. A group had seven nude mices, B group had five nude mices. A group nude mices were injected with MDA-MB-231 cells suspension into the second right mammary fat pad. Two weeks after emerged tumors, the orthotopic tumors of two nude mices of A group were dissected and then implanted into the second right mammary fat pad of B group nude mices. The other mices of A group continued to be fed. After six weeks of inoculation, we excised the tumors and the swollen lymph nodes in right axilla of all nude mices to make pathological examination. ① A group have a 7/7 tumor formation rate 7 days after implanted, B group was 5/5 5 days after implanted. ② The tumor volumes between the two groups had evident difference (P = 0.023), and the tumor volume of B group was bigger than A group. ③ A group had three nude mices which had one tumid lymph node respectively, the lymph node enlargement rate was 3/5; B group only had one nude mice that had one tumid lymph node, the lymph node enlargement rate was 1/5, the lymph node enlargement rate between the two groups showed no significant difference (P = 0.524). ④ The result of pathology in the two groups testified the tumors were invasive ductal carcinoma. The swollen lymph nodes in A group were reactive hyperplasia lymph nodes; the swollen lymph nodes in B group was metastatic lymph node. The method of orthotopic implantation with MDA-MB-231 tumor mass to establish lymph node metastasis of breast cancer model in nude mice, can provide a useful mean to research the lymph node metastasis mechanism of breast cancer.