  Due to over-metabolism, the tumour cells become hypoxic. To overcome this
situation tumour cells secret several chemical substrates to attract nearby
blood vessels towards it (angiogenesis). Transition from avascular to vascular
tumour is possible with the initiation of angiogenesis. Angiogenesis also plays
a crucial role to spread the cancer cells and its colonization at the distant
locations of the body (metastasis). In this paper, we briefly review the
processes and factors which directly affect tumour angiogenesis or may get
affected by it. A model based on cellular automata is developed to demonstrate
this complex process through MATLAB based simulation.
