Fig. 4.

Snapshots of the tumor islet without anisotropic collagen orientation ($k=0$) under a weak immune reaction. The blue, red and green circles denote the epithelial, cancer and T-lymphocytes, respectively. a t = 0 min, b t = 10 min, c t = 60 min, d t = 120 min, e t = 150 min, f t = 180 min, g t = 200 min, h t = 300 min and i t = 400 min