Breast cancer, and particularly the resulting metastases, continues to pose a major health risk for women. Studies in both in vitro and in vivo models have shown that tranilast has the potential to be used in the treatment of breast cancer as an anti-metastatic agent. This study looks at tranilast treatment response in relation to the particular receptor statuses of breast cancer. The objective of the study is to determine the effect of tranilast on the growth and migration of two human breast cancer cell lines BT 474 (receptor positive) and MDA MB 231 (receptor negative). Both cells lines showed a negative correlation between tranilast concentration and quantified proliferation at concentrations ranging from 50 ?mol/L to 200 ?mol/L. In the examination of migration, BT 474 and MDA MB 231 cells also exhibited slower wound closure after tranilast treatment (200 ?mol/L). Additionally, the extent of colony growth in a soft agar assay was reduced after tranilast treatment in both cell lines. Immunocytochemistry of tranilast and vehicle treated cells showed downregulation of two metastatic markers, endoglin and MMP-9, in both cell lines, though to a lesser extent in the MDA MB 231 cells. While tranilast treatment does exert inhibitory effects on both cell lines tested, BT 474 cells showed greater sensitivity with a larger reduction of proliferation and slower migration, as compared with MDA MB 231 cells. Tranilast may therefore be a potential therapeutic agent for breast cancer, and possibly functions through a receptor pathway.