MIGRATION OF COORDINATED CELL CLUSTERS IN MESENCHYMAL AND EPITHELIAL CANCER EXPLANTS IN-VITRO

The invasion and migration occurring in primary neoplastic tissue expl ants were studied by using a three-dimensional collagen matrix model, subsequent time-lapse videomicroscopy, and computer-assisted cell trac king. We show that not only single cells but groups of clustered cells comprising 5 to more than 100 cells detach from the primary tumor les ion and migrate within the adjacent extracellular matrix. These cluste rs were highly polarized, resulting in a high directional persistence of migration. Locomoting cell clusters were observed in primary cultur es from invasive oral squamous cell carcinomas (6 of 9), ductal breast carcinomas (2 of 3), and rhabdomyosarcoma (1 of 1), whereas normal or al mucosa (0 of 4) was cell cluster negative. Thus, locomoting cell cl usters could be a novel and potentially important mechanism of cancer cell invasion and metastasis.