- Cancer is a tumour.
- It is an abnormal growth or enlargement of tissue.
- It has no co-ordination with normal tissue.
- It is an independent,autonomus,uncontrolled growth of a tissue containing a mass of abnormal cells.
- A tumour serves no useful purpose but is harmful as it grows at the expense of the host like a parasite.
- Cancer now cause the second largest no.of deaths in most countries.
- There is no cure for cancer.
Types of tumour:
- The tumour is two types, namely benign tumour and malignant tumour.
- The benign tumour remains fixed in the place of origin.
- It will not spread from one place to other.
- It can be cured by surgically removing the tissue.
- It spread from one place to another through circulation and invasion.
- The spreading of tumour from one place to another is called metastasis.
Characteristics of Cancer:
- A tumour arises from an existing tissue or cells of the body.
- The growth of tumour is autonomous i.e. it follows
- its own laws of growth, it is not regulated by those governing the tissue from
- which or in which it grows.
- The tumour cells are undifferntiated and anaplastic in nature.
- Anaplasia refers to the reversion of differentiated cells into
- undifferentiated or embryonic cells.
- They have a greater potentially for growth and multiplication.
- They carry out none of the function of normal adult cells.
- They have large and irregular nuclei.
- They lose their contact inhibition.