Recognised as a key stage in cancer growth and spread in the human body, the cancer cell invasion process is crucial for metastatic spread and the subsequent development of secondary cancers. Tissue scale proliferation and migration in conjunction with a pallet of arising cell-scale dynamics including altered adhesion and secretion of matrix degrading enzymes enable the cancer cells to actively spread locally into the surrounding tissue. This biological multiscale character that cancer invasion exhibits therefore explores the natural two-way link between the molecular processes occurring at the level of individual cells (micro-scale) and the processes occurring at the level of cell population (macro-scale). This chapter will address these m...