Cancer cell migration in three-dimensional extracellular matrix is a major cause of death
for cancer patients. Although extensive studies have elucidated detailed mechanism of single
cell 3D invasion and cell-ECM interaction, 3D collective cancer invasion is still poorly
understood. 3D collective migration models have unveiled unexpected degrees of diversity and
adoption in migration and have an advantage over the 2D collective models by mimicking in
vivo conditions. To probe 3D collective cancer migration, diverse in vitro methods have been
designed to explore the physical factors that regulate the multicellular processes. The role of
ECM geometry and microstructure has been poorly understood in 3D collective cancer
migration.