Gastro-Intestinal Cancer

Cancer of the stomach or bowel.

Geiger Counter

Machine that measures the amount of radiation around it. Makes a series of clicks. The more clicks, the more radiation there is.

Gene
(Genes)

The genes are coded messages that tell cells how to behave and so control the growth and development of the body. Genes are made of DNA. They are grouped together to make the chromosomes. Each chromosome contains millions of genes. See Chromosome, Heredity.

Gene Therapy
(Molecular Therapy)

Treating cancer by repairing gene damage, or blocking the proteins that damaged genes make. See Chromosome, Gene.

Genetic Predisposition

If you have a 'genetic predisposition' to cancer, then you are more likely to develop it than the average person because of the genes you have inherited from your parents. See Breast Cancer Gene, Gene, Heredity.

Genital Wart Virus
(HPV, Human Papilloma Virus)

A virus which causes warts on the genitals and which increases the risk of developing cancer of the cervix.

Gland

An organ in the body which makes and secretes (gives off) a substance such as a hormone or a digestive enzyme. For example, the salivary glands make and secrete saliva; the thyroid gland makes and secretes thyroid hormones.

Glioblastoma

The most common brain tumor found in adults. Also called Grade IV astrocytoma.

Glioma
(Glial cells)

Group of types of brain tumor from a range of cells called glial cells. These make up the supporting tissue of the brain. Over half of all brain tumors are gliomas. Types include astrocytoma, ependymoma, oligodendroglioma. There are also mixed gliomas which contain more than one type of cell.

Goserelin
(Zoladex)

Drug which acts on the pituitary gland in the brain to stop the production of sex hormones. Used in the treatment of prostate and breast cancer. See also Pituitary Downregulators.

Grade

What the cancer cells look like under the microscope. The less they look like normal cells, the higher grade the cancer is said to be. Low grade cancers are thought less malignant than high grade. This means they are likely to grow more slowly and be less likely to spread.

Grade: Lymphomas

Grade is a way of grouping together types of lymphoma that are treated in more or less the same way. There are three grades of lymphomas: high, intermediate and low. When deciding on treatment, doctors usually group high and intermediate grades together. Low grade lymphomas are slower growing chronic diseases. They are often controlled for many years with fairly mild chemotherapy. But they are less likely to be completely curable. High grade lymphomas are usually faster growing acute diseases that need more intensive treatment, but are more often curable. See Chemotherapy, Lymphoma.

Grade: Solid Tumors

What the cancer cells look like under the microscope. The more they look like normal cells, the higher grade the cancer is said to be. High grade cancers are thought to be less malignant than low grade. This means they are likely to grow more slowly and be less likely to spread.

Graft Versus Host

A term used in donor bone marrow transplant. The graft (the donated marrow) reacts against the host (the person receiving the marrow). It can cause diarrhea, skin rashes and liver damage. Usually it is mild. It can be a good thing because it means the marrow has taken and is producing a good immune response which may help to kill cancer cells. See Allogeneic Transplant, Bone Marrow Transplant.
General practitioner - family doctor.

Growth Factors
(G-CSF, GM-CSF, Growth Factor, IL3)

Natural substances produced in tiny quantities in the body which help blood cells to grow. These can now be given in much larger doses by injection during chemotherapy treatment to help the bone marrow recover from treatment more quickly and make more blood cells.

Growth Cycle
(Cell Cycle)

The normal cycle of events a cell goes through when it is reproducing itself. See Cell Division.

Gut Sterilizers

Tablets given to some people having high dose chemotherapy, bone marrow or stem cell transplant. They kill off the bacteria that are normally present in the digestive system. In healthy people, these bacteria are not harmful. But in people with very little resistance to infection they can cause illness. See Bacteria, Bone Marrow Transplant, Digestive System, High Dose Chemotherapy, Stem Cell Transplant.