Tumour cell density (solid), ECM density (dashed), MDE concentration (dashdot), and endogenous inhibitors (dotted). Solutions to (8) with (4), (6), (7), (9), (10) and the parameter values γ = 0.005, η = 10, μ1 = 0.5, μ2 = 0.1, β = 0.07, du = dn = dm = 0.001, θ = 0.05, ξ = 0.03, and ρ = 0.07.