More than 200 kinds of cancer have been discovered, which may broadly be categorized into 4 major groups:
1. Carcinoma: Cancerous tumours caused by epithelial or endothelial cells, e.g. Brain tumours.
2. Sarcoma: Tumours inthe tissues of mesodermal origin, e.g. Bone cancer.
3. Lymphoma: Tumours of Lymph glands and Spleen, e.g. Hodhkins disease.
4. Leukemia: Blood cancer.
In addition to these, there may be mixed Malignant tumours.