  Cancer invasion of the surrounding tissue is a multiscale process that
involves not only tumour cells but also other immune cells in the environment,
such as the tumour-associated macrophages (TAMs). The heterogeneity of these
immune cells, with the two extremes being the pro-inflammatory and anti-tumour
M1 cells, and the anti-inflammatory and pro-tumour M2 cells, has a significant
impact on cancer invasion as these cell interact in different ways with the
tumour cells and with the ExtraCellular Matrix (ECM). Experimental studies have
shown that cancer cells co-migrate with TAMs, but the impact of these different
TAM sub-populations (which can change their phenotype and re-polarise depending
on the microenvironment) on this co-migration is not fully understood. In this
study, we extend a previous multi-scale moving boundary mathematical model, by
introducing the M1-like macrophages alongside with their exerted multi-scale
effects on the tumour invasion process. With the help of this model we
investigate numerically the impact of re-polarising the M2 TAMs into the
anti-tumoral M1 phenotype and how such a strategy affects the overall tumour
progression. In particular, we investigate numerically whether the M2-->M1
re-polarisation could depend on time and/or space, and what would be the
macroscopic effects of this spatial- and temporal-dependent re-polarisation on
tumour invasion.
