Cancer metastasis, the departure of cancer cells from the primary tumors and their spread to distant sites, is responsible for 90% of cancer related deaths. Thus, understanding the initial process which leads to cancer metastasis in the later stage and stopping the spread in the initial stage deems necessary. In spite of significant progress in diagnosis and treatment, there is still the need for robust and easy to use drug assessment methods. In this work we present two approaches for this purpose: a microengineered Boyden chamber, and a dielectrophoresis-based platform for cell characterization and drug assessment. Using these methods, we characterize the drug response of breast cancer, which is the second most common type of cancer among US women. The micorengineered Boyden chamber we designed in this work is made of a silicon-based transmigration well with a 30µm-thick membrane and 8µm pores. This platform includes a deep microfluidic channel on the back-side sealed with a glass wafer. Using this platform, the migratory behavior of highly metastatic breast cancer cells, MDA-MB231, is tested under different drug treatment conditions. The second platform, the off-chip passivated electrode insulator-based dielectrophoresis (OπDEP) device, has been used to first distinguish between different breast cancer cell lines namely LCC1/MCF7, LCC9/MCF7, MCF7, and MDA-MB231, and also to probe the effect of different drug treatments on the cells. These versatile platforms will enable the enhanced integration with other technologies and running multiple assays simultaneously. Moreover, the methods presented show potential for next generation drug discovery and patient follow up purposes. / Master of Science