We have developed a specialized JAVA-based version of DIAS (Dynamic Image Analysis System), J3D-DIAS 4.2, dedicated to the reconstruction and motion analysis of cancer cells, the aggregates they form, and the unique characteristic of coalescence between aggregates formed by cancer cells in a 3D gel.  Application of this system to the 4D analysis of cancerous and non-cancerous cells has revealed a variety of unique behaviors in cancer cell populations and has allowed us to identify specialized cell types that mediate coalescence in populations of tumor cells and human tumor tissue. This 4D analysis has also revealed a cell type that emerges from cancer cell preparations and translocates through interaggregate spaces at extraordinarily high velocities in a swirling pattern, playing no role in aggregate coalescence and exhibiting no cohesivity to aggregates.  Control preparations of cells from non-tumorigenic cell lines or from normal fresh tissue divide in the gel, but do not coalesce or form the specialized cell types. To demonstrate the usefulness of this system in assessing the role of anti-tumorigenic drugs, we have analyzed the aggregation process of cancer cells in the presence of monoclonal antibodies (mAb) and other drugs commonly used to treat cancer.