“…Let g i (υ (x + r,t) , c (x,t)) , i = 1, 2, describe the nature of the cell-cell and cell-matrix adhesive forces created at x due to signalling with cell/ECM components at x + r. These functions increase when the cell density and ECM density increase, and accordingly they decrease when the cell density and ECM density decrease. The functions g i , i = 1, 2, are chosen as in Bitsouni et al (2017) to be given by g 1 (υ (x + r,t) , c (x,t)) := S 1 (c (x,t)) u 1 (x + r,t) + S (c (x,t)) u 2 (x + r,t) +C 1 (c (x,t)) f (x + r,t) , (2.3) and g 2 (υ (x + r,t) , c (x,t)) := S 2 (c (x,t)) u 2 (x + r,t) + S (c (x,t)) u 1 (x + r,t) +C 2 (c (x,t)) f (x + r,t) , (2.4) 6 of 36 Vasiliki Bitsouni et al where S i (c (x,t)) is the cell-cell self-adhesion strength function for populations u i , S (c (x,t)) is the cell-cell cross-adhesion strength function between the two populations, and C i (c (x,t)) is the adhesion strength function between population u i and ECM. We should mention here that a similar term was considered before by Chaplain et al (2011).…”