Cancer gene test made simple

A new test has been developed that will make it much easier, faster and also cheaper to detect some genetic abnormalities that are associated with an increased risk of breast cancer. The American scientists who have developed the test say that it may have the potential to transform future breast cancer screening and treatment programmes. It is estimated that between five and ten per cent of breast cancer patients have an inheritable form of the disease.

The test identifies women who have a higher probability of having defective or mutated copies of two 'breast cancer genes', BRCA1 and BRCA2. In their 'normal' state, they protect against cancer within the cell. Women who carry a mutation in either of the genes have approximately an 80 per cent chance of developing breast cancer. Currently, women can be tested for defective copies of the two genes, but this involves full genetic sequencing which can take weeks, and is very expensive.

The new test, which has not been perfected yet but is still under development by the team at the Thomas Jefferson University in Philadelphia, does not actually search for the defective genes themselves, but for protein markers that are only made by healthy versions of the genes. The protein was discovered to bind itself to broken strands of DNA within a cell, and 'recruit' other molecules and substances to repair it. The new test uses an antibody protein which is 'aimed' at the breast cancer protein. If this protein is not found it indicates that there may be a defect in the genes, and a full gene sequence can then be done to confirm this presence.

The scientists, led by Dr Bruce Turner, believe that the easier discovery of the genes will be important because 'patients with breast cancer who have mutations in BRCA1 or BRCA2 may be better candidates for certain types of therapy'. 'They may be better candidates for mastectomy than lumpectomy and radiation therapy - also known as breast-conserving therapy'.