1 There are over 200 types of cancer.  Anything that may cause a normal body cell to develop abnormally potentially can cause cancer; general categories of cancer-related or causative agents are as follows: chemical or toxic compound exposures, ionizing radiation, some pathogens, and human genetics.
Chemotherapy uses anti cancer (cytotoxic) drugs to destroy cancer cells. For some types of brain tumour you may have chemotherapy after surgery, to try to prevent the tumour from coming back. Chemotherapy is sometimes given with radiotherapy and for some months afterwards to help people to live longer.hemotherapy works very well for some types of brain tumour but it does not work for all of them. You may have some types of chemotherapy in cycles. You have the drugs for a few days every few weeks.
Breast cancer tumours that are ER/PR-positive are 60% likely to respond to hormonal therapy. Tumours that are ER/PR negative are only 5% to 10% likely to respond to hormonal therapy. Hormonal therapies for breast cancer are treatments used after surgery, chemotherapy, and/or radiotherapy are finished.They are designed to help prevent recurrence of the disease by blocking the effects of oestrogen.bout 65% of these are also PR positive. They grow in response to another hormone, progesterone. If your breast cancerâs cells have a significant number of receptors for either oestrogen or progesterone, your cancer is considered hormone-receptor positive and will likely to respond to hormonal therapies.