Because of the following reasone normal cells do not show cancerous growth:
1.Their growth and division are regulated by certain regulatory mechanisms.
2.Division rate is slower.
3.Life span is definite.
4.They do not form a tumour.
In cancerous cells:
1.Regulators, control over their growth and division is lost.
2.Division rate is faster.
3.Life span is infinite.
4.Generally, these are tumorous.